Rear bicycle chainring assembly

Abstract

A rear sprocket assembly (11) of a bicycle, comprising: a first sprocket (15), comprising: a) a first sprocket body (47); b) a plurality of first sprocket teeth (49) provided on an outer circumference of the first sprocket body (47), the plurality of first sprocket teeth (49) comprising a first shifting initiation tooth (49a) and a second shifting initiation tooth (49b); c) a plurality of first circumferential regions, each comprising a first circumferential length (L1) corresponding to a single tooth spacing defined from a drive surface (49c) of a tooth of the first sprocket teeth (49) to a drive surface (49d) of an adjacent tooth of the first sprocket teeth (49), the adjacent tooth being adjacent to the tooth without any other tooth of the first sprocket teeth (49) intervening; wherein a first total number of the plurality of first circumferential regions is an even number;d) a first switch relief area (59a) in which the first switch initiation tooth (49a) is arranged; and e) a second switch relief area (59b) in which the second switch initiation tooth (49b) is arranged; and a second sprocket (14) comprising a second sprocket body (51) and a plurality of sprocket teeth (53) provided on an outer circumference of the sprocket body (51); wherein a first number of circumferential regions from a drive surface (49f) of the first shifting initiating tooth (49a) to a drive surface (49g) of the second shifting initiating tooth (49b) in a drive direction of rotation (D) with respect to a rotation center axis (A) of the rear bicycle sprocket assembly (11) is an odd number; a second number of circumferential regions from the drive surface (49g) of the second shifting initiating tooth (49b) to the drive surface (49f) of the first shifting initiating tooth (49a) in the drive direction of rotation (D) is an odd number;and wherein the first number of circumferential regions differs from the second number of circumferential regions; the second sprocket (14) is adjacent to the first sprocket (15) in an axial direction parallel to the axis of rotation (A) of the rear bicycle sprocket assembly (11) without any other sprocket arranged between the first sprocket (15) and the second sprocket (14); the plurality of first sprocket teeth (49) of the first sprocket (15) has an adjacent tooth (49h) which is adjacent on a forward side of the direction of drive rotation (D) from the second shifting initiating tooth (49b) without any other tooth between the second shifting initiating tooth (49b) and the adjacent tooth (49h) on the outer circumference of the sprocket body (47) to the second shifting initiating tooth (49b);the plurality of second sprocket teeth (53) has a chain support tooth (53a) which is arranged between the second shifting initiation tooth (49b) and the adjacent tooth (49h) in a circumferential direction with respect to the axis of rotation (A), viewed from the axial direction; and wherein the chain support tooth (53a) has a tooth height which is greater than that of the plurality of second sprocket teeth (53).

Description

This application claims priority over US patent application US 15 / 288,960, which was filed on October 7, 2016. The entire disclosure of US patent application US 15 / 288,960 is hereby incorporated by reference. Field of invention This invention relates generally to a rear bicycle chainring assembly. In particular, the present invention relates to a chainring of a rear chainring assembly that is configured to provide smooth and reliable shifting. Background information Cycling is becoming an increasingly popular form of recreation, as well as a means of transportation. Furthermore, cycling has become a very popular competitive sport for both amateurs and professionals. Whether the bicycle is used for leisure, transport, or competition, the bicycle industry is constantly improving its various components. One area that has undergone extensive revision over the years is the bicycle drivetrain. In particular, bicycle component manufacturers have continuously improved the shifting performance of various shifting components, such as derailleurs, derailleurs, chains, and chainrings. One specific component of the bicycle drivetrain that has undergone extensive redesign in recent years is the chainring assembly. In particular, chainring assemblies have been designed with improved sprockets to enable smoother and more reliable shifting. DE 10 2015 011 214 A1 describes a bicycle sprocket with a central pivot axis. The bicycle sprocket comprises a sprocket body and a chain engagement structure with a plurality of chain engagement teeth. US 5,545,096 A describes a sprocket mechanism. The sprocket mechanism includes two or more sprockets, each having two groups of teeth formed in a circumferential section and an additional tooth formed between the two groups of teeth. DE 601 14 957 T2 describes a sprocket assembly for a bicycle with at least one large sprocket and at least one small sprocket. The large sprocket is modified to allow a bicycle chain to move smoothly from the large sprocket to the small sprocket during an upshift. DE 10 2015 105 035 A1 describes a rear sprocket with a sprocket body and a chain engagement arrangement. The sprocket body has a central axis of rotation, a first side surface, and a second side surface. The first side surface is a smaller side of the sprocket body facing the sprocket. SUMMARY In general, the present disclosure is directed to various features of a rear bicycle chainring assembly. With regard to the prior art and according to a first aspect of the present disclosure, a rear bicycle sprocket assembly is provided, comprising a first sprocket with a first sprocket body and a plurality of first sprocket teeth provided on an outer circumference of the first sprocket body. The plurality of first sprocket teeth includes a first shifting tooth and a second shifting tooth. The first sprocket further comprises a plurality of first circumferential regions, each having a first circumferential length corresponding to a single tooth spacing defined from a driving face of a tooth of the first sprocket teeth to a driving face of an adjacent tooth of the first sprocket teeth. The adjacent tooth is adjacent to the tooth without any other tooth of the first sprocket teeth intervening.The first total number of the plurality of first circumferential areas is an even number. The rear bicycle chain assembly further comprises a second sprocket with a second sprocket body and a plurality of second sprocket teeth provided on an outer circumference of the second sprocket body. The first shifting tooth is located in a first shifting area, and the second shifting tooth is located in a second shifting area. The first number of circumferential areas from a drive surface of the first shifting tooth to a drive surface of the second shifting tooth in a drive direction with respect to a rotation center axis of the rear bicycle chain assembly is an odd number. The second number of circumferential areas from the drive surface of the second shifting tooth to the drive surface of the first shifting tooth in the drive direction is an odd number.The first number of circumferential areas differs from the second number of circumferential areas. According to the first aspect of the present invention, a rear bicycle chainring assembly is provided in which it is possible to reliably complete a shifting operation even when the total number of teeth on a bicycle chainring is an even number and the bicycle chainring has a plurality of shifting facilitation areas. The second chainring is adjacent to the first chainring in an axial direction parallel to the axis of rotation of the rear bicycle chainring assembly without any other chainring arranged between the first and second chainrings.The first chainring's multiple teeth have an adjacent tooth located on the outer circumference of the chainring body, adjacent to the second shifting tooth, on a side facing the direction of rotation of the drive. There is no other tooth between the second shifting tooth and the adjacent tooth. The second chainring's multiple teeth have a chain support tooth located between the second shifting tooth and the adjacent tooth in a circumferential direction relative to the axis of rotation, viewed from the axial direction. The chain support tooth has a height greater than that of the second chainring's multiple teeth. According to a second aspect of the present invention, the rear bicycle chainring assembly according to the first aspect is configured such that the second chainring further comprises a plurality of second circumferential sections, each of which has a second circumferential length corresponding to a single tooth spacing defined from a driving face of a tooth of the second chainring teeth to a driving face of an adjacent tooth of the second chainring teeth. The adjacent tooth is the tooth without any other tooth of the second chainring teeth intervening. The second total number of the plurality of second circumferential sections is an even number and less than the first total number of the plurality of first circumferential sections. The first total number of the plurality of first circumferential sections minus the second total number of the plurality of second circumferential sections is equal to or greater than two.According to the second aspect of the present invention, a rear bicycle chainring arrangement is provided in which it is possible to reliably complete a shifting operation even when the total number of teeth of a bicycle chainring is an even number and the bicycle chainring has a plurality of shifting facilitation areas. According to a third aspect of the present invention, the rear bicycle chainring assembly according to the second aspect is configured such that the plurality of first chainring teeth has an adjacent tooth located on the outer circumference of the first chainring body on a side facing the direction of drive rotation, from the second shifting tooth to the second shifting tooth, without any further tooth between the second shifting tooth and the adjacent tooth. The plurality of second chainring teeth has a chain support tooth located in a circumferential direction with respect to the axis of rotation, viewed from the axial direction, between the second shifting tooth and the adjacent tooth.According to the third aspect of the present invention, a rear bicycle chainring arrangement is provided in which it is possible to smoothly complete the shifting process in the second shift relief area in addition to the first shift relief area. According to a fourth aspect of the present invention, the rear bicycle chainring assembly according to the third aspect is configured such that the chain support tooth has a tooth height greater than that of the plurality of second chainring teeth. According to the fourth aspect of the present invention, a rear bicycle chainring assembly is provided in which it is possible to complete the shifting operation smoothly in the second shift relief range in addition to the first shift relief range. According to a fifth aspect of the present invention, the rear bicycle chainring assembly according to one of aspects two to four is configured such that the first shifting relief area and the second shifting relief area are configured to facilitate a shifting operation from the first chainring to the second chainring. According to the fifth aspect of the present invention, a rear bicycle chainring assembly is provided in which it is possible to reliably complete a shifting operation from a larger chainring to a smaller chainring (i.e., an upshift). According to a sixth aspect of the present invention, the rear bicycle chainring assembly according to any one of aspects two to five is configured such that the plurality of first chainring teeth are configured to engage with a bicycle chain having a plurality of outer link plates and a plurality of inner link plates. The first shifting engagement tooth and the second shifting engagement tooth are configured to engage with a pair of outer link plates when the bicycle chain shifts from the first chainring to the second chainring. The outer link plates in each pair of outer link plates face each other in the axial direction. According to the sixth aspect of the present invention, a rear bicycle chainring assembly is provided in which it is possible to complete the shifting operation smoothly. According to a seventh aspect of the present invention, the rear bicycle chainring assembly according to the sixth aspect is configured to prevent the bicycle chain from shifting from the first chainring to the second chainring when either the first or the second shifting tooth engages with a pair of inner plate plates. The inner plate plates in each pair of inner plate plates face each other axially. According to the seventh aspect of the present invention, a rear bicycle chainring assembly is provided in which it is possible to complete the shifting process smoothly. According to an eighth aspect of the present invention, the rear bicycle chainring assembly according to the third or fourth aspect is configured such that the chain support tooth has a recess on an axial end face facing the first chainring. According to the eighth aspect of the present invention, a rear bicycle chainring assembly is provided in which it is possible to complete the shifting process smoothly. According to a ninth aspect of the present invention, the rear bicycle chainring assembly according to the eighth aspect is configured such that a surface of the recess is designed to contact a bicycle chain during an upshifting operation. According to the ninth aspect of the present invention, a rear bicycle chainring assembly is provided in which it is possible to complete the shifting operation smoothly. According to a tenth aspect of the present invention, the rear bicycle chainring assembly according to any one of aspects two to nine is configured such that the first chainring further comprises a third shifting facilitation area, which is configured to facilitate a shifting operation from the second chainring to the first chainring. According to the tenth aspect of the present invention, a rear bicycle chainring assembly is provided in which it is possible to reliably complete a shifting operation from a smaller chainring to a larger chainring (i.e., a downshifting operation). According to an eleventh aspect of the present invention, the rear bicycle chainring assembly according to the tenth aspect is configured such that the third shift relief area partially overlaps with the first shift relief area. According to the eleventh aspect of the present invention, a rear bicycle chainring assembly is provided in which it is possible to increase the number of drive teeth even if a bicycle chainring has an upshift relief area and a downshift relief area. According to a twelfth aspect of the present invention, a rear bicycle chainring assembly is provided, which basically comprises a first chainring having a first chainring body with a plurality of angular segments resulting from uniformly dividing the first chainring body into even and equal or greater than ten angular segments. A plurality of first chainring teeth is provided on an outer circumference of the first chainring body. The plurality of first chainring teeth comprises a first shifting tooth and a second shifting tooth. The first shifting tooth is entirely located within a first angular segment under the plurality of angular segments, and the second shifting tooth is entirely located within a second angular segment under the plurality of angular segments. The first total number of the plurality of angular segments is an even number.The first shifting tooth is located in a first shifting relief area, and the second shifting tooth is located in a second shifting relief area. The rear bicycle chain assembly further comprises a second sprocket with a second sprocket body and a plurality of second sprocket teeth provided on an outer circumference of the second sprocket body. The first number of angular segments from the first angular segment to a third angular segment in a drive direction with respect to a rotational center axis of the rear bicycle chain assembly is odd. The second number of angular segments from the second angular segment to a fourth angular segment in the drive direction is odd.The third angular segment is adjacent to the second angular segment on an upstream or front side of the drive direction of rotation, without any further angular segment between the second and third angular segments. The fourth angular segment is adjacent to the first angular segment on an front side of the drive direction of rotation, without any further angular segment between the first and fourth angular segments. The first number of angular segments differs from the second number of angular segments. According to the twelfth aspect of the present invention, a rear bicycle chainring arrangement is provided in which it is possible to reliably complete a shifting operation even when the total number of teeth on a bicycle chainring is an even number and the bicycle chainring has a plurality of shifting facilitation areas.The second sprocket is adjacent to the first sprocket in an axial direction parallel to the axis of rotation of the rear bicycle chainring assembly, without any other sprocket positioned between the first and second sprockets. The first sprocket's multiple teeth include an adjacent tooth located on the outer circumference of the sprocket body, adjacent to the second shifting tooth, on a side facing the direction of drive rotation, without any other tooth between the second shifting tooth and the adjacent tooth. The second sprocket's multiple teeth include a chain support tooth positioned between the second shifting tooth and the adjacent tooth in a circumferential direction relative to the axis of rotation, viewed from the axial direction.The chain support tooth has a tooth height that is greater than that of the multitude of second sprocket teeth. According to a thirteenth aspect of the present invention, the rear bicycle sprocket assembly according to the twelfth aspect is configured such that the second sprocket body has a plurality of angular segments resulting from the second sprocket body being evenly divided into ten angular segments equal to or greater than ten. The second total number of angular segments in the plurality is an even number and less than the first total number of angular segments in the plurality of the first sprocket. The first total number of angular segments in the plurality of the first sprocket minus the second total number of angular segments in the plurality of the second sprocket is equal to or greater than two.According to the thirteenth aspect of the present invention, a rear bicycle chainring arrangement is provided in which it is possible to reliably complete a shifting operation even when the total number of teeth of a bicycle chainring is an even number and the bicycle chainring has a plurality of shifting facilitation areas. According to a fourteenth aspect of the present invention, the rear bicycle chainring assembly according to the thirteenth aspect is configured such that the first shift facilitation area and the second shift facilitation area are configured to facilitate a shifting operation from the first chainring to the second chainring. According to the fourteenth aspect of the present invention, a rear bicycle chainring assembly is provided in which it is possible to reliably complete a shifting operation from a larger chainring to a smaller chainring (i.e., an upshifting operation). According to a fifteenth aspect of the present invention, the rear bicycle chainring assembly according to the thirteenth aspect is configured such that the first chainring further comprises a third shifting facilitation area, which is configured to facilitate a shifting operation from the second chainring to the first chainring. According to the fifteenth aspect of the present invention, a rear bicycle chainring assembly is provided in which it is possible to reliably complete a shifting operation from a smaller chainring to a larger chainring (i.e., a downshifting operation). Furthermore, additional tasks, features, aspects and advantages of the disclosed rear bicycle chainring arrangement will become apparent to the person skilled in the art from the following detailed description, which, in conjunction with the accompanying drawings, reveals exemplary embodiments of the rear bicycle chainring arrangement. BRIEF DESCRIPTION OF THE DRAWINGS Reference is now made to the accompanying drawings, which form part of this original disclosure: Fig. 1 is a side view of a rear bicycle chainring assembly according to one embodiment shown; Fig. 2 is a rear view of the rear bicycle chainring assembly of Fig. 1; Fig. 3 is a small chainring side view of a chainring with thirty-four teeth of the rear bicycle chainring assembly of Fig. 1; Fig. 4 is a small chainring side view of a thirty-tooth chainring of the rear bicycle chainring assembly of Fig. 1; Fig. 5 is a small chainring side view of a twenty-six-tooth chainring of the rear bicycle chainring assembly of Fig. 1; Fig. 6 is a small chainring side view of a twenty-three-tooth chainring of the rear bicycle chainring assembly of Fig. 1; Fig. 7 is a small chainring side view of a twenty-tooth chainring of the rear bicycle chainring assembly of Fig. 1; Fig.Fig. 8 is a side view of an eighteen-tooth sprocket of the rear bicycle chainring assembly of Fig. 1; Fig. 9 is a partial top view of a chain support tooth of the eighteen-tooth sprocket of Fig. 8; Fig. 10 is a side view of a sixteen-tooth sprocket of the rear bicycle chainring assembly of Fig. 1; Fig. 11 is a side view of a fourteen-tooth sprocket of the rear bicycle chainring assembly of Fig. 1; Fig. 12 is a partial top view of a chain support tooth of the fourteen-tooth sprocket of Fig. 11; Fig. 13 is a side view of a twelve-tooth sprocket of the rear bicycle chainring assembly of Fig. 1; Fig. 14 is a small sprocket side view of the twelve-tooth sprocket and the fourteen-tooth sprocket coupled together; Fig. 15 is a small sprocket side view of the fourteen-tooth sprocket and the sixteen-tooth sprocket coupled together; Fig.Fig. 16 is a small sprocket side view of the sixteen-tooth and eighteen-tooth sprockets coupled together; Fig. 17 is a small sprocket side view of the eighteen-tooth and twenty-tooth sprockets coupled together; Fig. 18 is a perspective view of a bicycle chain during a downshifting operation; Fig. 19 is a small sprocket side view of the bicycle chain during the downshifting operation shown in Fig. 18; Fig. 20 is a perspective large sprocket side view of a chain support tooth of the fourteen-tooth sprocket; Fig. 21 is a top view of the chain support tooth of Fig. 20; Fig. 22 is a front view in cross-section of the chain support wheel of Fig. 20, which carries a bicycle chain; Fig. 23 is a small sprocket side view of the sixteen-tooth sprocket, which is divided into sixteen angular segments; and Fig.Figure 24 is a small sprocket side view of the fourteen-tooth sprocket, which is divided into fourteen angular segments. DETAILED DESCRIPTION OF EXAMPLE EXECUTIONS Selected embodiments will now be explained with reference to the drawings. It will be apparent to those skilled in the field of bicycles from this disclosure that the following descriptions of the exemplary embodiments are provided for illustrative purposes only and not for the purpose of limiting the invention as defined by the attached claims and their equivalents. Since the various parts of a bicycle are well known in bicycle technology, these parts of the bicycle are not discussed or illustrated in detail herein, except when they are modified according to the exemplary embodiments of the present invention. It is obvious to a person skilled in the art of bicycles from this disclosure that a rear bicycle chainring assembly according to the exemplary embodiments of the present invention can have a different number of chainrings. Figures 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23 to 24 show a rear bicycle chainring assembly 11 according to an exemplary embodiment of the present invention. As shown in Figures 1 and 2, the rear bicycle chainring assembly 11 has nine chainrings 13 to 21. The chainrings 13 to 21 are axially spaced apart from each other at predetermined intervals. The sprockets 13 to 21 are arranged to be fixed to a rear bicycle hub assembly, such that the sprockets 13 to 21 are arranged to rotate together around a central axis of rotation A. The sprockets 13 to 21 typically rotate together in a drive direction D (e.g., in a clockwise direction, as shown in Fig.(as shown in Figure 1) when the rider pedals in a forward direction (clockwise) to propel the bicycle forward. It will be apparent to a person skilled in the art of bicycles from this disclosure that the rear sprocket assembly may have fewer or more sprockets. As shown in Figures 1 and 2, the sprockets 13 to 21 are hard, rigid, disc-shaped elements made of a suitable material, for example, a metallic material. In the illustrated exemplary embodiment, the sprockets 13 to 21 are each a single, unified element made of a metallic material suitable for a bicycle sprocket. Referring to Figure 2, the sprocket assembly 11 is shown with arrows indicating the directions of an upshift and a downshift. An upshift occurs when a bicycle chain 23 (Figures 18 and 19) is moved from a large sprocket to the next smaller sprocket, while a downshift occurs when the bicycle chain 23 is moved from a small sprocket to the next larger sprocket.The chainrings 13 to 21 are designed to allow the bicycle chain to perform smooth and reliable upshifting and downshifting movements. The chainrings 13 to 21 may feature modified teeth, such as teeth with angled faces, and / or cutouts to facilitate upshifting and downshifting, as described in detail below. In the illustrated exemplary embodiment, the rear sprocket assembly 11 of the present invention has a tooth configuration of 12T-14T-16T-18T-20T-23T-26T-30T-34T for the respective sprockets 13 to 21. It is obvious to a person skilled in the bicycle industry from this disclosure that the sprockets 13 to 21 can have other tooth configurations. When the sprocket assembly 11 is rotated clockwise, as shown in Fig. 1, the inner and outer link plates 23a and 23b of a bicycle chain 23 (Figs. 18 and 19) engage with the teeth of one of the sprockets. In the case of a sprocket with an even number of teeth, such as sprockets 13 to 17 and 19 to 21, the inner and outer link plates 23a and 23b always engage with the same teeth. In the case of a sprocket with an odd number of teeth, the inner and outer link plates 23a and 23b engage with different teeth alternately with each rotation of the sprocket assembly 11. Therefore, the teeth of the sprocket 18 (with an odd number of teeth) will engage alternately with the inner and outer link plates 23a and 23b. Referring to Figures 2 and 3, the sprocket 21 basically comprises a sprocket body 24 and a plurality (thirty-four) of circumferentially spaced teeth 25, which extend radially and outwards from an outer circumference of the sprocket body 24. The term "outer circumference of the sprocket body," as used here, lies on a circle corresponding to the root diameter of the teeth 25. The sprocket body 24 has a first axial side, or small sprocket side 24a, which faces the next smaller sprocket (sprocket 20), and a second axial side, or large sprocket side 24b, which faces the bicycle wheel. The center of the sprocket 21 is provided with a splined bore 24c, which is mounted on the freewheel (not shown) of the bicycle rear hub assembly in a conventional manner. Referring to Figures 2 and 4, the sprocket 20 basically comprises a sprocket body 27 and a plurality (thirty) of circumferentially spaced teeth 29, which extend radially and outwards from an outer circumference of the sprocket body 27. The sprocket body 27 has a first axial side or small sprocket side 27a, which faces the next smaller sprocket (sprocket 19), and a second axial side or large sprocket side 27b, which faces the next larger sprocket (sprocket 21). The center of the sprocket 20 is provided with a splined bore 27c, which is mounted on the freewheel (not shown) of the rear bicycle hub assembly in a conventional manner. Referring to Figures 2 and 5, the sprocket 19 basically comprises a sprocket body 31 and a plurality (twenty-six) of circumferentially spaced teeth 33, which extend radially and outwards from an outer circumference of the sprocket body 31. The sprocket body 31 has a first axial side or small sprocket side 31a, which faces the next smaller sprocket (sprocket 18), and a second axial side or large sprocket side 31b, which faces the next larger sprocket (sprocket 20). The center of the sprocket 19 is provided with a splined bore 31c, which is mounted on the freewheel (not shown) of the rear bicycle hub assembly in a conventional manner. Referring to Figures 2 and 6, the sprocket 18 basically comprises a sprocket body 35 and a plurality (twenty-three) of circumferentially spaced teeth 37, which extend radially and outwards from an outer circumference of the sprocket body 35. The sprocket body 35 has a first axial side or small sprocket side 35a, which faces the next smaller sprocket (sprocket 17), and a second axial side or large sprocket side 35b, which faces the next larger sprocket (sprocket 19). The center of the sprocket 18 is provided with a splined bore 35c, which is mounted on the freewheel (not shown) of the rear bicycle hub assembly in a conventional manner. Referring to Figures 2 and 7, the sprocket 17 basically comprises a sprocket body 39 and a plurality (twenty) of circumferentially spaced teeth 41, which extend radially and outwards from an outer circumference of the sprocket body 39. The sprocket body 39 has a first axial side or small sprocket side 39a, which faces the next smaller sprocket (sprocket 16), and a second axial side or large sprocket side 39b, which faces the next larger sprocket (sprocket 18). The center of the sprocket 17 is provided with a splined bore 39c, which is mounted on the freewheel (not shown) of the rear bicycle hub assembly in a conventional manner. Referring to Figures 2 and 8, the sprocket 16 basically comprises a sprocket body 43 and a plurality (eighteen) of circumferentially spaced teeth 45, which extend radially and outwards from an outer circumference of the sprocket body 43. The sprocket body 43 has a first axial side or small sprocket side 43a, which faces the next smaller sprocket (sprocket 15), and a second axial side or large sprocket side 43b, which faces the next larger sprocket (sprocket 17). The center of the sprocket 16 is provided with a splined bore 43c, which is mounted on the freewheel (not shown) of the rear bicycle hub assembly in a conventional manner. Referring to Figures 2 and 10, the sprocket 15 basically comprises a sprocket body 47 and a plurality (sixteen) of circumferentially spaced teeth 49, which extend radially and outwards from an outer circumference of the sprocket body 47. The sprocket body 47 has a first axial side or small sprocket side 47a, which faces the next smaller sprocket (sprocket 14), and a second axial side or large sprocket side 47b, which faces the next larger sprocket (sprocket 16). The center of the sprocket 15 is provided with a splined bore 47c, which is mounted on the freewheel (not shown) of the rear bicycle hub assembly in a conventional manner. Referring to Figures 2 and 11, the sprocket 14 basically comprises a sprocket body 51 and a plurality (fourteen) of circumferentially spaced teeth 53, which extend radially and outwards from an outer circumference of the sprocket body 51. The sprocket body 51 has a first axial side or small sprocket side 51a, which faces the next smaller sprocket (sprocket 13), and a second axial side or large sprocket side 51b, which faces the next larger sprocket (sprocket 15). The center of the sprocket 14 is provided with a splined bore 51c, which is mounted on the freewheel (not shown) of the rear bicycle hub assembly in a conventional manner. Referring to Fig. 2 and Fig. 13, the sprocket 13 basically comprises a sprocket body 55 and a plurality (twelve) of circumferentially spaced teeth 57, which extend radially and outwards from an outer circumference of the sprocket body 55. The sprocket body 55 has a first axial side or small sprocket side 55a, which faces outwards from the bicycle, and a second axial side or large sprocket side 55b, which faces the next larger sprocket (sprocket 14). The center of the sprocket 13 is provided with a splined bore 55c, which is mounted on the freewheel (not shown) of the rear bicycle hub assembly in a conventional manner. The rear bicycle chainring assembly 11 comprises a first chainring, for example, the chainring 15 shown in Fig. 10. The chainring 15 has the chainring body 47 and the plurality of chainring teeth 49 provided on an outer circumference of the chainring body 47. The plurality of chainring teeth 49 has a first shifting initiation tooth 49a and a second shifting initiation tooth 49b. The first shifting initiation tooth 49a is arranged in a first shifting relief area 59a. The second shifting initiation tooth 49b is arranged in a second shifting relief area 59b. The chainring 15 may further have a third shifting relief area 59c. The third shifting relief area 59c partially overlaps the first shifting relief area 59a, as shown in Fig. 10. The first shift relief area 59a and the second shift relief area 59b are configured to facilitate a shift from sprocket 15 (i.e., the first sprocket) to sprocket 14 (i.e., the second sprocket). Accordingly, the first and second shift relief areas 59a and 59b facilitate an upshift. As shown in Fig. 10, the first and second shift relief areas 59a and 59b are not diametrically opposed; that is, a line passing through the center of the first shift relief area 59a and the axis of rotation A does not pass through the center of the second shift relief area 59b. The third shift relief area 59c is configured to facilitate a shift from sprocket 14 (i.e., the second sprocket) to sprocket 15 (i.e., the first sprocket). Accordingly, the third shift relief area 59c facilitates a downshift.Each of the first to third switch relief areas 59a to 59c contains an axially recessed section 59d to 59f. The axially recessed sections 59d and 59e are upshifting recessed sections, and the axial recessed section 59f is a downshifting recessed section. The upshifting recessed sections 59d and 59e are designed to reduce interference between the bicycle chain 23 and the sprocket 15 during upshifting from the sprocket 15 to the sprocket 14. The downshifting recessed section 59f is designed to reduce interference between the bicycle chain 23 and the bicycle sprocket 15 during downshifting from the sprocket 14 to the sprocket 15. Each of the upshifting recessed sections 59d and 59e and the downshifting recessed section 59f are provided on the first axial side 47a of the sprocket body 47. The sprocket 15 has a plurality of circumferential regions. Each circumferential region has a circumferential length corresponding to a single tooth spacing defined from a driving face of one sprocket tooth to a driving face of an adjacent sprocket tooth. The adjacent tooth is the tooth that is directly adjacent to the tooth without any other sprocket tooth in between. For example, a first circumferential length L1, shown in Fig. 10, extends from the driving face 49c of one tooth to the driving face 49d of the adjacent tooth and corresponds to the first circumferential region A1. A second circumferential length L2 extends from the driving face 49d of the adjacent tooth to the driving face 49e of the next adjacent tooth and corresponds to a second circumferential region A2.However, if the adjacent tooth, which has the drive surface 49e, is missing to provide a gap between the sprocket teeth, the circumferential length is still L2, since the circumferential length is based on the individual tooth spacing and not just the distance between adjacent teeth. Accordingly, the sprocket 15 has sixteen circumferential lengths L and thus sixteen circumferential regions A. Therefore, the total number of the plurality of circumferential regions for the sprocket 15 is an even number. The first number of circumferential regions from the drive surface 49f of the first shifting tooth 49a to the drive surface 49g of the second shifting tooth 49b in the drive direction D with respect to a rotational center axis A of the rear bicycle chainring assembly 11 is an odd number. As shown in Fig. 10, the first number of circumferential regions for the chainring 15 from the drive surface 49f of the first shifting tooth 49a to the drive surface 49g of the second shifting tooth 49b in the drive direction D with respect to the rotational center axis A of the rear bicycle chainring assembly 11 is nine. The second number of circumferential regions from the drive surface 49g of the second shifting tooth 49b to the drive surface 49f of the first shifting tooth 49a in the drive direction D with respect to a rotational center axis A of the rear bicycle chainring assembly 11 is an odd number. As shown in Fig.As shown in Figure 10, the second number of circumferential areas for the chainring 15, from the drive surface 49g of the second shifting tooth 49b to the drive surface 49f of the first shifting tooth 49a in the drive direction D with respect to the axis of rotation A of the rear bicycle chainring assembly 11, is seven. The first number of circumferential areas for the chainring 15 (i.e., the first chainring) is nine, and the second number of circumferential areas is seven. Accordingly, the first number of circumferential areas differs from the second number of circumferential areas for the chainring 15 (i.e., the first chainring). The rear bicycle chainring assembly 11 further comprises a second chainring, such as the chainring 14 shown in Fig. 11. The chainring 14 (i.e., the second chainring) is adjacent to the chainring 15 (i.e., the first chainring) in an axial direction parallel to the axis of rotation A of the rear bicycle chainring assembly 11, without any other chainring arranged between the chainring 15 and the chainring 14. As shown in Figs. 1 and 2, the chainring 14 is arranged on an outwardly facing side 47a of the chainring 15, without any other chainring arranged between it. The sprocket 14 comprises the sprocket body 51 and a plurality of sprocket teeth 53, which, as shown in Fig. 11, are provided on an outer circumference of the sprocket body 51. The plurality of sprocket teeth 53 includes a chain support tooth 53a, which, as shown in Fig. 7, is arranged between the second shifting inlet tooth 49b and the adjacent tooth 49h in a circumferential direction with respect to the axis of rotation A, viewed from the axial direction. The chain support tooth 53a has, as shown in Figs. 11, 14, and 15, a tooth height that is greater than that of the plurality of second sprocket teeth; that is, the chain support tooth 53a has the greatest tooth height of the plurality of teeth 53 of the sprocket 14 (i.e., the second sprocket). The chain support tooth 53a has, as shown in Fig. 12 and Fig. 14, a recess 53b on an axial end face 51b which faces the sprocket 15 (i.e. the first sprocket).An upper surface 53c of the recess 53b is arranged such that, as shown in Fig. 22, it contacts the bicycle chain 23 during an upshifting operation. During the shifting of the chain 23 from the sprocket 15 to the sprocket 14, the upper surface 53c of the chain support tooth 53a supports the chain 23 to enable a smooth and reliable upshifting operation. The pair of inner plate plates 23b is arranged between a tooth 49 of the sprocket 15 and the chain support tooth 53a during the upshifting operation, as shown in Figs. 18, 19 and 22, and the pair of inner plate plates 23b is supported by the chain support tooth 53a. The sprocket 14 has a plurality of circumferential regions. Each circumferential region has a circumferential length corresponding to a single tooth spacing defined from a driving face of one tooth of the sprocket teeth 53 to a driving face of an adjacent tooth of the sprocket teeth 53. The adjacent tooth is the tooth next to the tooth without any other tooth of the sprocket 14 in between. For example, a first circumferential length L1, shown in Fig. 11, extends from a driving face 53d of one sprocket tooth to a driving face 53e of the adjacent tooth. A second circumferential length L2 extends from the driving face 53e of the sprocket tooth to the driving face 53f of the adjacent tooth. Accordingly, the sprocket 14 (i.e., the second sprocket) has fourteen circumferential lengths and thus fourteen circumferential regions. Consequently, the total number of the plurality of circumferential regions for the sprocket 14 is an even number.The total number of multiple circumferential ranges for sprocket 14 (i.e., the second sprocket) is less than the total number of multiple circumferential ranges for sprocket 15 (i.e., the first sprocket). The total number of multiple circumferential ranges for sprocket 15 minus the total number of multiple circumferential ranges for sprocket 14 is equal to or greater than two (i.e., 16 - 14 = 2). As shown in Fig. 14, the sprocket 14 has a first shift relief area 53g and a second shift relief area 53h, which are configured to facilitate a shift from the sprocket 14 to the sprocket 13. Accordingly, the first and second shift relief areas 53g and 53h facilitate an upshift. As shown in Fig. 14, the first and second shift relief areas 53g and 53h are diametrically opposed, i.e., a line passing through the center of the first shift relief area 53g and the axis of rotation A passes through the center of the second shift relief area 53h. A third shift relief area 53i is configured to facilitate a shift from the sprocket 13 to the sprocket 14. The third shift relief area 53i partially overlaps the first shift relief area 53g.A first switching initiation tooth 53j is located entirely within the first switching relief area 53g. A second switching initiation tooth 53k is located entirely within a second switching relief area 53h. The chain support tooth 53a is located entirely outside the first, second, and third switching relief areas 53g, 53h, and 53i. The sprocket 15 (i.e., the first sprocket) and the sprocket 14 (i.e., the second sprocket) are shown coupled together in Fig. 15. The plurality of sprocket teeth 49 of the sprocket 15 has an adjacent tooth 49h, which is located on a forward side of the drive direction of rotation adjacent to the second shifting initiating tooth 49b without any other tooth between the second shifting initiating tooth 49b and the adjacent tooth 49h on the outer circumference of the sprocket body 47 to the second shifting initiating tooth 49b. The plurality of sprocket teeth 53 of the sprocket 14 (i.e., the second sprocket) has a chain support tooth 53a, which is arranged between the second shifting initiation tooth 49b and the adjacent tooth 49h in a circumferential direction with respect to the axis of rotation when viewed from the axial direction. As shown in Figs. 15, 20 and 21, the chain support tooth 53a of the sprocket 14 is arranged between the second shifting initiation tooth 49b and the adjacent tooth 49h of the sprocket 15 in the circumferential direction with respect to the axis of rotation A when viewed from the axial direction. The plurality of sprocket teeth 49 of the chainring 15 (i.e., the first chainring) is configured to engage with the bicycle chain 23, which, as shown in Figs. 18 and 21, has a plurality of outer plate plates 23a and a plurality of inner plate plates 23b. The first shifting tooth 49a and the second shifting tooth 49b are configured to engage with a pair of outer plate plates 23a when the bicycle chain 23 shifts from the chainring 15 (i.e., the first chainring) to the chainring 14 (i.e., the second chainring). The outer plate plates 23a in each pair face each other in the axial direction. The bicycle chain 23 is prevented from shifting from the chainring 15 to the chainring 14 when either the first or second shifting tooth engages with a pair of inner plate plates 23b. The inner tab plates 23b in each pair face each other in the axial direction. As shown in Fig. 7, the sprocket 17 comprises the sprocket body 39 and a plurality of sprocket teeth 41 provided on an outer circumference of the sprocket body 39. The plurality of sprocket teeth 41 includes a first shifting initiation tooth 41a and a second shifting initiation tooth 41b. The first shifting initiation tooth 41a is arranged in a first shifting relief area 61a. The second shifting initiation tooth 41b is arranged in a second shifting relief area 61b. The sprocket 17 may further include a third shifting relief area 61c. As shown in Fig. 7, the third shifting relief area 61c partially overlaps the first shifting relief area 61a. The first shift relief area 61a and the second shift relief area 61b are configured to facilitate a shift from sprocket 17 to sprocket 16. Accordingly, the first and second shift relief areas 61a and 61b facilitate an upshift. As shown in Fig. 7, the first and second shift relief areas 61a and 61b are not diametrically opposed; that is, a line passing through the center of the first shift relief area 61a and the axis of rotation A does not pass through the center of the second shift relief area 61b. The third shift relief area 61c is configured to facilitate a shift from sprocket 16 to sprocket 17. Accordingly, the third shift relief area 61c facilitates a downshift.Each of the first to third switch relief areas 61a to 61c has an axial recess section 61d to 61f. The axially recessed sections 61d and 61e are upshifting recess sections, and the axial recess section 61f is a downshifting recess section. The upshifting recess sections 61d and 61e are designed to reduce interference between the bicycle chain 23 and the sprocket 17 during upshifting from the sprocket 17 to the sprocket 16. The downshifting recess section 61f is designed to reduce interference between the bicycle chain 23 and the bicycle sprocket 17 during downshifting from the sprocket 16 to the sprocket 17. Each of the upshifting recess sections 61d and 61e and the downshifting recess section 61f are provided on the first axial side 39a of the sprocket body 39. The sprocket 17 has a plurality of circumferential regions A. Each circumferential region A has a circumferential length L corresponding to a single tooth spacing defined from a driving face of one sprocket tooth to a driving face of an adjacent sprocket tooth. The adjacent tooth is the tooth that is directly next to the tooth without any other tooth of the sprocket 17 intervening. For example, a first circumferential length L1, shown in Fig. 7, extends from the driving face 41c of one tooth to the driving face 41d of the adjacent tooth and corresponds to the first circumferential region A1. A second circumferential length L2 extends from the driving face 41d of the adjacent tooth to the driving face 41e of the next adjacent tooth and corresponds to a second circumferential region A2.However, if the adjacent tooth, which has the drive surface 41e, is missing to provide a gap between the sprocket teeth, the circumferential length is still L2, as shown, since the circumferential length is based on the individual tooth spacing and not just on the distance between these drive surfaces of adjacent teeth. Accordingly, the sprocket 17 has twenty circumferential lengths L and thus twenty circumferential regions A. Consequently, the total number of the plurality of circumferential regions for the sprocket 17 is an even number. The first number of circumferential regions from the drive surface 41f of the first shifting tooth 41a to the drive surface 41g of the second shifting tooth 41b in the drive direction D with respect to a rotational center axis A of the rear bicycle chainring assembly 11 is an odd number. As shown in Fig. 7, the first number of circumferential regions for the chainring 17 from the drive surface 41f of the first shifting tooth 41a to the drive surface 41g of the second shifting tooth 41b in the drive direction D with respect to the rotational center axis A of the rear bicycle chainring assembly 11 is eleven. The second number of circumferential regions from the drive surface 41g of the second shifting tooth 41b to the drive surface 41f of the first shifting tooth 41a in the drive direction D with respect to a rotational center axis A of the rear bicycle chainring assembly 11 is an odd number. As shown in Fig.As shown in Figure 7, the second number of circumferential sections for the chainring 17, from the drive surface 41g of the second shifting tooth 41b to the drive surface 41f of the first shifting tooth 41a in the drive direction D with respect to the axis of rotation A of the rear bicycle chainring assembly 11, is nine. The first number of circumferential sections for the chainring 17 is eleven, and the second number of circumferential sections is nine. Accordingly, the first number of circumferential sections differs from the second number of circumferential sections for the chainring 17. The sprocket 16, in an axial direction parallel to the axis of rotation A of the rear bicycle sprocket assembly 11, is adjacent to the sprocket 17 without any other sprocket being arranged between the sprocket 17 and the sprocket 16. As shown in Figs. 1 and 2, the sprocket 16 is arranged on an outwardly facing side 39a of the sprocket 17 without any other sprocket being arranged between them. The sprocket 16 comprises the sprocket body 43 and a plurality of sprocket teeth 45 arranged on an outer circumference of the sprocket body 43, as shown in Fig. 6. The plurality of sprocket teeth 45 includes a chain support tooth 45a, which, as shown in Fig. 17, is arranged between the second shifting inlet tooth 41b and the adjacent tooth 41h in a circumferential direction with respect to the axis of rotation A, when viewed from the axial direction. The chain support tooth 45a has a tooth height greater than that of the plurality of sprocket teeth; that is, the chain support tooth 45a has the greatest tooth height of the plurality of teeth 45 of the sprocket 16, as shown in Figs. 8, 16, and 17. The chain support tooth 45a has a recess 45b on an axial end face 43b which, as shown in Fig. 9, faces the sprocket 17.An upper surface 45c of the recess 45b is arranged to touch the bicycle chain 23 during an upshifting process. The sprocket 16 has a plurality of circumferential regions. Each circumferential region has a circumferential length corresponding to a single tooth spacing defined from a drive face of one tooth of the sprocket teeth 45 to a drive face of an adjacent tooth of the sprocket teeth 45. The adjacent tooth is the tooth next to the tooth, with no other tooth of the sprocket 16 in between. For example, a first circumferential length L1, shown in Fig. 8, extends from a drive face 45d of one sprocket tooth to a drive face 45e of the adjacent tooth. A second circumferential length L2 extends from the drive face 45e of the sprocket tooth to the drive face 45f of the adjacent tooth. Accordingly, the sprocket 16 has eighteen circumferential lengths and thus eighteen circumferential regions. Therefore, the total number of the plurality of circumferential regions for the sprocket 16 is an even number.The total number of multiple circumferential areas for sprocket 16 is less than the total number of multiple circumferential areas for sprocket 17. The total number of multiple circumferential areas for sprocket 17 minus the total number of multiple circumferential areas for sprocket 16 is equal to or greater than two (i.e., 20 - 18 = 2). The sprocket 16 has a first shift relief area 45g and a second shift relief area 45h, which are configured to facilitate a shifting operation from the sprocket 16 to the sprocket 15, as shown in Fig. 16. Accordingly, the first and second shift relief areas 45g and 45h facilitate an upshift. As shown in Fig. 16, the first and second shift relief areas 45g and 45h are diametrically opposed, i.e., a line passing through the center point of the first shift relief area 45g and the axis of rotation A passes through the center point of the second shift relief area 45h. A third shift relief area 45i is configured to facilitate a shifting operation from the sprocket 15 to the sprocket 16. The third shift relief area 45i partially overlaps the first shift relief area 45g.A first switching initiation tooth 45j is located entirely within the first switching relief area 45g. A second switching initiation tooth 45k is located entirely within the second switching relief area 45h. The chain support tooth 45a is located entirely outside the first, second, and third switching relief areas 45g, 45h, and 45i. The sprocket 17 and the sprocket 16 are shown coupled together in Fig. 17. The plurality of sprocket teeth 41 of the sprocket 17 has an adjacent tooth 41h, which is adjacent to the second shifting initiation tooth 41b without any further tooth between the second shifting initiation tooth 41b and the adjacent tooth 41h on the outer circumference of the sprocket body 39 in a side upstream of the drive direction of rotation from the second shifting initiation tooth 41b. The multiple sprocket teeth 45 of the sprocket 16 include the chain support tooth 45a, which is arranged between the second shifting initiation tooth 41b and the adjacent tooth 41h in a circumferential direction with respect to the axis of rotation when viewed from the axial direction. As shown in Fig. 17, the chain support tooth 45a of the sprocket 16 is arranged between the second shifting initiation tooth 41b and the adjacent tooth 41h of the sprocket 17 in the circumferential direction with respect to the axis of rotation A when viewed from the axial direction. The remaining sprockets, which have an even number of teeth, can be configured similarly to those described above. A description of these is omitted here for the sake of brevity. Referring to Figures 23 and 24, the sprockets 15 and 14 are divided into a plurality of angular segments. Each angular segment is formed by dividing the sprocket evenly into ten, equal, or greater than ten angular segments. The designs of the sprockets 15 and 14 are, as described above, essentially identical, except that they are divided into angular segments (instead of circumferential sections), so a repeated description of this is omitted. As shown in Fig. 23, the sprocket 15 (i.e., the first sprocket) has a plurality of angular segments S, which result when the sprocket body 47 is evenly divided into ten segments equal to or greater than ten. The sprocket 15 has sixteen angular segments. Accordingly, the first total number of the plurality of angular segments S of the sprocket 15 is an even number. The first switching initiating tooth 49a is completely arranged within a first angular segment S1 among the plurality of angular segments, as shown in Fig. 23. The second switching initiating tooth 49b is completely arranged within a second angular segment S2 among the plurality of angular segments. The first angular segment S1 is not diametrically opposite the second angular segment S2. A third angular segment S3 is located on an upstream side of the drive direction D, without any angular segments between the second angular segment S2 and the third angular segment S3, adjacent to the second angular segment S2. A fourth angular segment S4 is located on an upstream side of the drive direction D, without any angular segments between the first angular segment S1 and the fourth angular segment S4, adjacent to the first angular segment S1. The third angular segment S3 is not diametrically opposite the fourth angular segment S4. The first number of angular segments, from the first angular segment S1 to the third angular segment S3 in a drive direction of rotation D with respect to a rotational center axis A of the rear bicycle sprocket assembly 11, is an odd number. As shown in Fig. 23, the first number of angular segments is nine. The second number of angular segments, from the second angular segment S2 to the fourth angular segment S4 in the drive direction, is also an odd number. The second number of angular segments is seven. Accordingly, the first number of angular segments (nine) differs from the second number of angular segments (seven). As shown in Fig. 24, the sprocket 14 (i.e., the second sprocket) has a plurality of angular segments S, which result when the sprocket body 51 is divided uniformly into even and equal to or greater than ten angular segments S. A second plurality of angular segments S is an even number and less than the first plurality of angular segments of the sprocket 15 (i.e., the first sprocket). The second plurality of angular segments of the sprocket 14 is fourteen. Accordingly, the second plurality of angular segments is an even number less than the first plurality of angular segments of the sprocket 15 (sixteen angular segments). The first plurality of angular segments of the sprocket 15 (i.e., the first sprocket) minus the second plurality of angular segments of the sprocket 14 (i.e., the second sprocket) is equal to or greater than two (i.e., 16 - 14 = 2). For the purposes of understanding the scope of the present invention, the term "comprise" and its variations, as used herein, are intended as open terms that specify the presence of the aforementioned features, elements, components, groups, integers, and / or steps, but do not exclude the presence of other unmentioned features, elements, components, groups, integers, and / or steps. The foregoing also applies to words with a similar meaning, such as "include," "exist," and their variations. Furthermore, the terms "part," "section," "section," "link," or "element," when used in the singular, may have the dual meaning of a single part or a plurality of parts, unless otherwise stated. As used herein, the following directional terms, "side facing the frame," "side away from the frame," "forward," "backward," "front," "backward," "upward," "downward," "above," "below," "sideways," "vertical," "horizontal," "perpendicular," and "transverse," as well as any other similar directional terms, denote such directions of a bicycle in an upright riding position, equipped with the bicycle control device. Similarly, these directional terms, as used to describe the bicycle control device, shall be understood in relation to a bicycle in an upright riding position on a horizontal surface, equipped with the bicycle control device.The terms "left" and "right" are used to refer to "right" as the right side of a bicycle when viewed from the rear end of the bicycle and "left" as the left side when viewed from the rear end of the bicycle. It will also be understood that, despite the possible use of the terms "first" and "second" at this point to describe different components, these components are not thereby to be considered limited. The terms serve solely to distinguish one component from another. For example, a first component, as described above, could therefore also be referred to as a second component, and vice versa, without deviating from the teaching of the present invention. In the present embodiment, the terms "attached" or "fastening," as used here, include configurations in which an element is directly attached to another element by means of an attaching element; configurations in which the element is indirectly attached to the other element by means of an intermediate member; or configurations in which the element is indirectly attached to the other element by means of an intermediate member.Intermediate links are attached / will be attached; and configurations in which one element is integral with another, i.e., one element is essentially a part of the other. This concept also applies to words of similar meaning, such as "connected," "coupled," "fastened," "linked," "permanently attached," and their variations. Finally, terms of degree such as "essentially," "approximately," and "approximately," as used here, signify a proportionate degree of deviation from the modified concept, such that the end result is not substantially altered. While only selected embodiments have been chosen to illustrate the present invention, it will be clear to those skilled in the art of bicycles from the present disclosure that numerous changes and modifications can be made without deviating from the scope of the invention as defined by the appended claims. For example, unless expressly stated otherwise, the size, shape, location, or orientation of various components can be changed as needed and / or desired, provided that the changes do not substantially affect the intended function. The functions of one element can be performed by two elements, and vice versa, unless expressly stated otherwise. The structures and functions of one embodiment can be adopted in another embodiment.It is not necessary for all advantages to be present simultaneously in a particular embodiment. Each feature that is unique with respect to the prior art may, alone or in combination with other features, be considered a separate description of further inventions by the applicant, including structural and / or functional concepts embodied by such features. The preceding descriptions of embodiments according to the present invention are therefore provided for illustrative purposes only and not for the purpose of limiting the invention as defined by the attached claims and their equivalents.

Claims

A rear sprocket assembly (11) of a bicycle, comprising: a first sprocket (15), comprising: a) a first sprocket body (47); b) a plurality of first sprocket teeth (49) provided on an outer circumference of the first sprocket body (47), the plurality of first sprocket teeth (49) comprising a first shifting initiation tooth (49a) and a second shifting initiation tooth (49b); c) a plurality of first circumferential regions, each comprising a first circumferential length (L1) corresponding to a single tooth spacing defined from a drive surface (49c) of a tooth of the first sprocket teeth (49) to a drive surface (49d) of an adjacent tooth of the first sprocket teeth (49), the adjacent tooth being adjacent to the tooth without any other tooth of the first sprocket teeth (49) intervening; wherein a first total number of the plurality of first circumferential regions is an even number;d) a first switch relief area (59a) in which the first switch initiation tooth (49a) is arranged; and e) a second switch relief area (59b) in which the second switch initiation tooth (49b) is arranged; and a second sprocket (14) comprising a second sprocket body (51) and a plurality of sprocket teeth (53) provided on an outer circumference of the sprocket body (51); wherein a first number of circumferential regions from a drive surface (49f) of the first shifting initiating tooth (49a) to a drive surface (49g) of the second shifting initiating tooth (49b) in a drive direction of rotation (D) with respect to a rotation center axis (A) of the rear bicycle sprocket assembly (11) is an odd number; a second number of circumferential regions from the drive surface (49g) of the second shifting initiating tooth (49b) to the drive surface (49f) of the first shifting initiating tooth (49a) in the drive direction of rotation (D) is an odd number;and wherein the first number of circumferential regions differs from the second number of circumferential regions; the second sprocket (14) is adjacent to the first sprocket (15) in an axial direction parallel to the axis of rotation (A) of the rear bicycle sprocket assembly (11) without any other sprocket arranged between the first sprocket (15) and the second sprocket (14); the plurality of first sprocket teeth (49) of the first sprocket (15) has an adjacent tooth (49h) which is adjacent on a forward side of the direction of drive rotation (D) from the second shifting initiating tooth (49b) without any other tooth between the second shifting initiating tooth (49b) and the adjacent tooth (49h) on the outer circumference of the sprocket body (47) to the second shifting initiating tooth (49b);the plurality of second sprocket teeth (53) has a chain support tooth (53a) which is arranged between the second shifting initiation tooth (49b) and the adjacent tooth (49h) in a circumferential direction with respect to the axis of rotation (A), viewed from the axial direction; and wherein the chain support tooth (53a) has a tooth height which is greater than that of the plurality of second sprocket teeth (53). Rear bicycle chainring assembly (11) according to claim 1, wherein the second chainring (14) has a plurality of second circumferential regions, each of which has a second circumferential length (L2) corresponding to a single tooth spacing defined from a drive surface (53e) of a tooth of the second chainring teeth (53) to a drive surface (53f) of an adjacent tooth of the second chainring teeth (53), wherein the adjacent tooth is adjacent to the tooth without any other tooth of the second chainring teeth (53) intervening; wherein a second total number of the plurality of second circumferential regions is an even number and less than the first total number of the plurality of first circumferential regions; and the first total number of the plurality of first circumferential regions minus the second total number of the plurality of second circumferential regions is equal to or greater than two. Rear bicycle chainring assembly (11) according to claim 2, wherein the first switch facilitation area (59a) and the second switch facilitation area (59b) are arranged to facilitate a switching operation from the first chainring (15) to the second chainring (14). Rear bicycle chainring assembly (11) according to one of claims 2 to 3, wherein the plurality of first chainring teeth (49) is configured to engage with a bicycle chain (23) having a plurality of outer plate plates (23b) and a plurality of inner plate plates (23a); and the first shifting initiation tooth (49a) and the second shifting initiation tooth (49b) are configured to engage with a pair of outer plate plates (23b) when the bicycle chain (23) shifts from the first chainring (15) to the second chainring (14), wherein the outer plate plates (23b) in each of the pairs of outer plate plates (23b) face each other in the axial direction. Rear bicycle chainring assembly (11) according to claim 4, wherein it is prevented that the bicycle chain (23) is switched from the first chainring (15) to the second chainring (14) when either the first shifting initiating tooth (49a) or the second shifting initiating tooth (49b) engages with a pair of inner plate plates (23a), wherein the inner plate plates (23a) in each of the pairs of inner plate plates (23a) are axially oriented towards each other. Rear bicycle chainring assembly (11) according to claim 2, wherein the chain support tooth (53a) has a recess (53b) on an axial end face (51b) facing the first chainring (15). Rear bicycle chainring assembly (11) according to claim 6, wherein a surface (53c) of the recess (53b) is configured to contact a bicycle chain (23) during an upshifting process. Rear bicycle chainring assembly (11) according to one of claims 2 to 7, wherein the first chainring (15) further comprises a third shift facilitation area (59c) which is arranged to facilitate a shifting operation from the second chainring (14) to the first chainring (15). Rear bicycle chainring assembly (11) according to claim 8, wherein the third switch relief area (59c) partially overlaps the first switch relief area (59a). A rear sprocket assembly (11) of a bicycle, comprising: a first sprocket (15) comprising: a) a first sprocket body (47) with a plurality of angular segments (S) resulting from the first sprocket body (47) being evenly divided into ten angular segments (S) equal to or greater than ten; b) a plurality of first sprocket teeth (49) provided on an outer circumference of the first sprocket body (47), the plurality of first sprocket teeth (49) comprising a first shifting inset tooth (49a) and a second shifting inset tooth (49b), the first shifting inset tooth (49a) being entirely within a first angular segment (S1) below the plurality of angular segments (S) and the second shifting inset tooth (49b) being entirely within a second angular segment (S2) below the plurality of angular segments (S); wherein a first total number of the plurality of angular segments (S) is an even number;c) a first shift-facilitation area (59a) in which the first shift-initiation tooth (49a) is arranged; and d) a second shift-facilitation area (59b) in which the second shift-initiation tooth (49b) is arranged; and a second sprocket (14) comprising a second sprocket body (51) and a plurality of sprocket teeth (53) provided on an outer circumference of the sprocket body (51); wherein a first number of angular segments (S) from the first angular segment (S1) to a third angular segment (S3) in a drive direction of rotation (D) with respect to a rotation center axis (A) of the rear bicycle sprocket assembly (11) is an odd number; a second number of angular segments (S) from the second angular segment (S2) to a fourth angular segment (S4) in the drive direction of rotation (D) is an odd number;the third angular segment (S3) is adjacent to the second angular segment (S2) on an upstream side of the drive direction of rotation (D) without another angular segment (S) between the second angular segment (S2) and the third angular segment (S3); the fourth angular segment (S4) is adjacent to the first angular segment (S1) on an upstream side of the drive direction of rotation (D) without another angular segment (S) between the first angular segment (S1) and the fourth angular segment (S4); and the first number of angular segments (S) differs from the second number of angular segments (S); the second sprocket (14) is adjacent to the first sprocket (15) in an axial direction parallel to the axis of rotation (A) of the rear bicycle sprocket assembly (11) without another sprocket arranged between the first sprocket (15) and the second sprocket (14);the plurality of first sprocket teeth (49) of the first sprocket (15) has an adjacent tooth (49h) which is adjacent to the second shifting initiating tooth (49b) on a forward side of the drive direction of rotation (D) without any other tooth between the second shifting initiating tooth (49b) and the adjacent tooth (49h) on the outer circumference of the sprocket body (47) to the second shifting initiating tooth (49b); the plurality of second sprocket teeth (53) has a chain support tooth (53a) which is arranged between the second shifting initiating tooth (49b) and the adjacent tooth (49h) in a circumferential direction with respect to the axis of rotation (A), viewed from the axial direction; and wherein the chain support tooth (53a) has a tooth height which is greater than that of the plurality of second sprocket teeth (53). Rear bicycle chainring assembly (11) according to claim 10, wherein the second chainring (14) comprises a) a plurality of angular segments (S) of the second chainring body (51) resulting from the second chainring body (51) being evenly divided into an even number of angular segments (S) equal to or greater than ten; wherein a second total number of the plurality of angular segments (S) is an even number and less than the first total number of the plurality of angular segments (S) of the first chainring (15); and wherein the first total number of the plurality of angular segments (S) of the first chainring (15) minus the second total number of the plurality of angular segments (S) of the second chainring is equal to or greater than two. Rear bicycle chainring assembly (11) according to claim 11, wherein the first switch facilitation area (59a) and the second switch facilitation area (59b) are arranged to facilitate a switching operation from the first chainring (15) to the second chainring (14). Rear bicycle chainring assembly (11) according to claim 11, wherein the first chainring (15) further comprises a third shift facilitation area (59c) which is configured to facilitate a shifting operation from the second chainring (14) to the first chainring (15).

Images