Bicycle suspension stem system

Abstract

A suspension stem system for bicycles featuring a pre-load insert with elastomeric elements. The system can include a steerer-tube clamp / stem tube combination that can have integrated bearings. This system can allow the system to pivot the stem tube with an installed handlebar. The roller bearings can provide a higher degree of stiffness and reduced wear versus bushings, enabling shorter stem lengths. Elastomer shape, durometer, and preload geometry may allow tuning of the suspension stem system and improve durability over traditional designs.

Description

BICYCLE SUSPENSION STEM SYSTEMTECHNICAL FIELD

[0001] The present invention relates to a suspension stem for bicycles that includes multiple members disposed within the suspension stem, configured to reduce shock for a user when a handlebar is secured within the suspension stem and installed on a steerer tube of a bicycle.BACKGROUND

[0002] Suspension stems, which can provide compliance between a bicycle’s handlebar and a steerer tube, are well established in prior art.

[0003] Suspension stems typically fall into two categories: single-pivot designs, and four-bar linkage designs. A critical goal of any suspension stem is the minimizing of play or “slop” in the pivot joint(s). This is due to the fact that any play within the joint is magnified across the width of the handlebar. Furthermore, looseness or play in the pivot joint can compromise the steering precision of the bicycle.

[0004] The geometry of modern bicycles has evolved over the years as riding styles and handling requirements have changed. Modern bicycles trend toward having longer top tube lengths with shorter stem lengths. Due to the space required to incorporate one or more pivots and suspension elements within the stem, many existing suspension stem designs are inherently incompatible with these shorter required stem lengths. The design described below attempts to solve the problems described above.SUMMARY

[0005] This disclosure relates to bicycle suspension stem systems, where a suspension stem can comprise a steerer-tube clamp structured and configured to attach to a steerer tube; a stem tube can be disposed on the steerer-tube clamp, wherein the stem tube can be structured to secure and / or receive a handlebar. In such an embodiment, there can also be a steerer-tube clamp that can include at least one transverse bore, and where the stem tube can include at least one stem-tube bore, and may also have at least one pivot shaft that can be structured to allow the stem tube to pivot about an aligned transverse bore and stem-tube bore. This embodiment can also include at least one elastic element that may be disposed within the stem tube between the steerer-tube clamp and the handlebar, where at least one elastic element can compress upon the securing of the handlebar, and where the stem tube can be set up in such a way as to allow a vertical pivotal range of movement about an included pivot shaft.

[0006] In an alternative to the embodiment described above, there can also be a preload insert, where the preload insert can be disposed within the stem tube, between the secured handlebar and at least one elastic element.

[0007] In another alternative of the embodiment described above, there may be at least one elastic element wherein the at least one elastic element can be configured to pivot the stem tube upward in the vertical pivotal range and resist downward movement in the vertical pivotal range upon the securing of the handlebar.

[0008] In another alternative of the embodiment described above, there may be a rebound-elastic element that can be disposed within the stem tube, between the handlebar and the steerer-tube clamp.

[0009] In another alternative of the embodiment described above, there can be a faceplate that may be disposed on the stem tube and configured to hold the handlebar in a fixed position, and the faceplate can be attached to the stem tube with faceplate bolts.

[0010] In another alternative of the embodiment described above, there can be a backstop that may be disposed between the steerer-tube clamp and at least one elastic element.

[0011] In another alternative of the embodiment described above, there can be at least one bearing where the bearing can be disposed within the transverse bore, or the bearing can be disposed within each stem-tube bore.

[0012] In another alternative of the embodiment described above, there can be bearings that may be secured via an interference press fit, and also pivot shafts where each pivot shaft can be secured via an interference press fit into each bearing.

[0013] In another alternative of the embodiment described above, there can be a bearing that can be a roller bearing, and where the pivot shaft can also be an interference fit directly through rollers of the roller bearing.

[0014] In another alternative of the embodiment described above, there can be a steerer-tube clamp that may include a protrusion that can house the transverse bore, and where the reboundelastic element can be disposed between the protrusion and the preload insert.

[0015] In an another embodiment of a suspension stem, there can be a steerer-tube clamp configured to attach to a steerer tube, where the steerer-tube clamp can have a front side and a rear side, where the steerer-tube clamp may include at least one transverse bore, at least one pivot shaft that can be disposed within the at least one transverse bore, where the pivot shaft can be structured to allow a stem tube to pivot about the transverse bore. In this embodiment, the stem tube can be disposed on the front side of the steerer-tube clamp, where the stem tube may include at least one stem-tube bore for each pivot shaft, and further where the stem tube can be configured to securea handlebar, and where an elastic element can be disposed within the stem tube, between the handlebar and the steerer-tube clamp, and further where the elastic element can be structured and configured to compress upon the securing of the handlebar, and to pivot the stem tube upward in a vertical pivotal range and resist downward movement in the vertical pivotal range upon the securing of the handlebar.

[0016] In an alternative of the embodiment described above, there can also be a rebound-elastic element that can be disposed within the stem tube, between the handlebar and the steerer-tube clamp.

[0017] In an alternative of the embodiment described above, there can also be a faceplate that can be disposed on the stem tube and configured to hold the handlebar in a fixed position, and where the faceplate may be attached to the stem tube with faceplate bolts.

[0018] In an alternative of the embodiment described above, there can also be a backstop that may be disposed between the steerer-tube clamp and at least one elastic element.

[0019] In an alternative of the embodiment described above, there can also be at least one bearing wherein the at least one bearing can be disposed within each transverse bore, or the bearing can be disposed within each stem-tube bore in the stem tube. Additionally, each bearing may be secured via an interference press fit, and each pivot shaft may be secured via an interference press fit into each bearing.

[0020] In an alternative of the embodiment described above, there can also be an arrangement where the steerer-tube clamp can include a protrusion that may house the transverse bore, where the rebound-elastic element can be disposed between the protrusion and the handlebar.

[0021] In an alternative of the embodiment described above, there can also be a preload insert, where the preload insert can be disposed within the stem tube, between the secured handlebar and at least one elastic element. Additionally, each bearing can be a roller bearing, and the pivot shaft can be an interference fit directly through the roller bearing.

[0022] The above summary is not intended to describe each and every example or every implementation of the disclosure. The description that follows more particularly exemplifies various illustrative embodiments.BRIEF DESCRIPTION OF DRAWINGS

[0023] FIG. l is a front perspective view of one embodiment of a suspension stem system.

[0024] FIG. 2 is a rear perspective view of one embodiment of the suspension stem system.

[0025] FIG. 3 is an exploded view of FIG. 1.

[0026] FIG. 4 is a partial front perspective of a first portion of the suspension stem system.

[0027] FIG. 5 is a partial front perspective of a second portion of the suspension stem system.

[0028] FIG. 6Ais a top view of an un-preloaded suspension stem system.

[0029] FIG. 6B is a cross-sectional view of the FIG. 6A along the A-axis.

[0030] FIG. 6C is a side view of the un-preloaded suspension stem system for FIG. 6A.

[0031] FIG. 7Ais a top view of a preloaded suspension stem system.

[0032] FIG. 7B is a cross-sectional view of the FIG. 7A along the B-axis.

[0033] FIG. 7C is a side view of the preloaded suspension stem system for FIG. 7A.

[0034] FIG. 8A is a partial rear perspective view of the internal elements of an embodiment of a second portion of the suspension stem system.

[0035] FIG. 8B is a partial bottom perspective view of the internal elements of an embodiment of a second portion of the suspension stem system.

[0036] FIG. 9Ais a side view of an embodiment of the suspension stem system.

[0037] FIG. 9B is a cross-sectional view of FIG. 9A along the C-axis.

[0038] FIG. lOAis a side view of another embodiment of the suspension stem system.

[0039] FIG. 10B is a cross-sectional view of FIG. 109A along the D-axis.DETAILED DESCRIPTION

[0040] The present disclosure relates to suspension stems for bicycles that can include elastic elements to preload the resistance within a suspension stem system. Various embodiments of the suspension stem system will be described in detail with reference to the drawings, wherein like reference numerals represent like parts and assemblies throughout the several views. Reference to various embodiments does not limit the scope of the suspension stem system disclosed herein. Additionally, any examples set forth in this description are not intended to be limiting and merely set forth some of the many possible embodiments for the suspension stem system. It is understood that various omissions and substitutions of equivalents are contemplated as circumstances may suggest or render expedient, but these are intended to cover applications or embodiments without departing from the spirit or scope of the disclosure. Also, it is to be understood that the phraseology and terminology used herein are for the purpose of description and should not be regarded as limiting.

[0041] This disclosure describes a pivoting suspension stem, with at least one pivot location being located as close as practically possible to the axis of the steerer tube. The preloading principles described within this disclosure could be applied to both single-pivot type suspension stems as well as four-bar linkage type designs.

[0042] This disclosure describes a novel design and method of preloading a suspension stem, which together allow for shorter stem lengths than existing suspension stem designs.

[0043] In a first embodiment of a suspension stem system 100, a steerer tube clamp 101 can attach to a steerer tube of a bicycle using conventional means. As shown in FIGs. 1-3, a steerer tube clamp 101 can have a bearing protrusion 101 A on its front side near its upper end. The protrusion 101 A may include a transverse bore 101B sized such that two roller bearings 105 can be press-fit into either side of the transverse bore 101B; a bearing spacer 106 may also be disposed between the two bearings. The width of the bearing protrusion 101 A can be sized to closely fit within the inner width 102 A of a stem tube 102. On the front upper side of the bearing protrusion 101A, there can be an additional wedge-shaped protrusion 101C that can extend further forward, and may provide a reaction surface for a rebound elastomer 109 to bear against.

[0044] Such an embodiment may also include a stem tube 102, which may be approximately rectangular in cross section, with rounded corners, and can have an inner dimension 102 A of the tube profile that can be sized to fit closely over the steerer tube clamp bearing protrusion 101 A. There may also be a stem-tube bore 102B on either side of the stem tube 102 which can be aligned concentrically with an axis of the roller bearing 105, and where a pivot shaft 104 can pass through the stem-tube bores 102B, roller bearings 105, and a bearing spacer 106, which may then connect the stem tube 102 rotatably to a steerer tube clamp 101. In such an embodiment, the pivot shaft 104 can be secured to the stem tube 102 by means of an interference press-fit between the pivot shaft 104 and the stem -tube bores 102B. However, other common methods of securing a shaft may be used in lieu of an interference press-fit.

[0045] The front end of the stem tube 102 can feature a cylindrical handlebar cutout 102C shaped to accept a standard bicycle handlebar. The stem face plate 103 can attach to the front end of the stem tube 102 via four faceplate bolts 112, which can clamp a handlebar securely between the faceplate 103 and the cylindrical handlebar cutout 102C on the stem tube 102 when tightened.

[0046] The interior of the stem tube 102 can house a subassembly that can consist of a preload insert 108, one or more elastomer springs 107, and a rebound elastomer 109. Embodiments of this subassembly are shown in FIGs. 3 and 8A-B. In such embodiments, there can be two roughly rectangular-prism-shaped elastomer springs 107 and 307, which can be loosely secured to the preload insert 108 and 308 by means of an interference fit, below the axis of the pivot shaft in the various embodiments. The preload inserts 108 and 308 can be shaped to slide closely within the interior of the various embodiments of the stem tubes along their longitudinal axis. The front of the preload insert 108 and 308 can feature a cylindrical cutout 108 A and 308 A shaped to accept a standard bicycle handlebar.

[0047] In the embodiment shown in Figure 3, a backstop 110 can be inserted into the stem tube 102 between the elastomers 107 and the front of the steerer tube clamp 101. The backstop 110 may fill the gap between the bottom, rear of the stem tube 102, and the front of the steerer tube clamp 101, and can prevent the elastomers 107 from being damaged by the opening and closing of the gap as the stem tube 102 moves up and down through its pivotal range of travel.

[0048] An embodiment of the suspension stem system 200, as shown in FIGs. 6A-6C, where FIG. 6B is a cross-sectional view of Axis A in FIG. 6A, when installed into the stem tube 202, the elastomer springs 207 can be located largely below the axis of the pivot shaft 204. In the fore-aft direction, the elastomer springs 207 can be positioned between the rear surface of the preload insert 208 and the front surfaces of the backstop 210 and steerer tube clamp 201. In their unpreloaded state, shown in FIGs. 6A-C, the elastomers 207 can be sized such that the cylindrical handlebar cutout 208A on the front of the preload insert 208 can protrude slightly beyond the cylindrical handlebar cutout of the stem tube 202.

[0049] As shown in FIGs. 7A-C, where FIG. 7B is a cross-sectional view of Axis B in FIG. 7A, when the handlebar is clamped into place between the faceplate 213 and stem tube 202, the clamping pressure from the stem face plate bolts 212 can push the preload insert 208 rearward within the stem tube 202, which may compress the elastomer springs 207 between the preload insert 208 and the backstop 210. This can have the effect of forcing the stem tube 202 to rotate upward relative to the steerer tube clamp 201, effectively preloading the stem tube 202 to resist movement in the downward direction.

[0050] As shown in FIGs. 7A-C, the rearward movement of the preload insert 208 during installation of the handlebar may also force the rebound elastomer 209, which can be loosely contained within a cavity, such as cavity 308B of FIG. 8A, at the rear of the preload insert 208, against the wedge-shaped protrusion 201C on the front of the steerer tube clamp 201. This can have the effect of preloading the stem tube 202 to resist movement in the upward direction. The balance between the forces provided by the elastomer spring(s) 207 and the rebound elastomer 208 can reduce excess free movement when the stem is lightly loaded in either direction.

[0051] During use, when a rider encounters an impact, the front wheel of the bicycle moves upward, and the weight of the rider’s body on the handlebar causes the stem to rotate / pivot downward relative to the front wheel. During such use, an embodiment of the stem tube 202 can rotate / pivot downward relative to the steerer tube clamp 201, the space between the backstop 210 and the preload insert 208 may become smaller, compressing the elastomer springs 207 and increasing the force acting to rotate the stem tube 202 back upward.

[0052] Conversely, if the rider pulls upward on the handlebars (for example, to lift the front wheel of the bicycle over an obstacle), the stem tube 202 and preload insert 208 may rotate upward relative to the steerer tube clamp 201, further compressing the rebound elastomer 209 between the preload insert 208 and the wedge shaped protrusion 201C on the front of the steerer tube clamp 201. The compression of the rebound elastomer 209 can soften the “top-out” feel of the stem tube 202 as it approaches the end of its upward travel range.

[0053] Illustrated in FIGs. 9A-B and 10A-B are embodiments described herein that may utilize roller bearings 205, 405, and 505, where the rollers are directly in contact with the pivot shafts204, 404, and 504 of their respective embodiments. Compared to ball bearings, roller bearings205, 405, and 505 can have much higher effective load ratings due to the larger contact surface between the rollers and the shaft. They are also much more compact diametrically than equivalent ball bearings, allowing the pivot shafts 204, 404, and 504 axes to move closer to the steerer tube axis, effectively shortening the minimum stem length that can be constructed.

[0054] The embodiments illustrated in FIGs. 9A-B and 10A-B disclose various construction methods of suspension stem systems, for example, in FIGs. 9A-B, a pair of bearings 405 can be inserted within the transverse bore of the steerer clamp 401. FIG. 9B is a cross-sectional view of FIG. 9A along the C-axis. In this embodiment, there is an additional spacer 406; other embodiments may not require such a spacer nor a second bearing. In this example, the bearing may be secured via an interference press fit, and the pivot shaft may also be secured via an interference press fit into each bearing. Additionally, each bearing can be a roller bearing, and the pivot shaft can also be an interference fit that is directly through the rollers of the roller bearing 405.

[0055] In FIGs. 10A-B, an alternative arrangement may take place where a pair of bearings 505 can be inserted within the stem-tube bores of the stem tube 502. FIG. 10B is a cross-sectional view of FIG. 10A along the D-axis. Just like the embodiment in FIGs. 9A-B, the bearings in FIGs. 10A-B may be secured via an interference press fit, and the pivot shaft may also be secured via an interference press fit into each bearing. Additionally, each bearing can be a roller bearing, and the pivot shaft 504 can also be an interference fit that is directly through rollers of the roller bearings 505.

[0056] Compared to sliding bushings, which require some degree of initial clearance to allow the shaft to rotate within the bushing, roller bearings allow the pivot joint to be constructed with zero clearance between components. This results in a dramatically stiffer joint with less play between components. The roller bearing joint is also much less prone to additional wear over the lifespan of the component compared to a sliding bushing.

[0057] In the embodiment shown in FIGs 1-2, the axis of the pivot shaft 104 can be located above the centerline axis of the stem tube 102, as close to the top surface of the stem tube 102 as practically possible. This can allow the elastomer springs ( not shown) to be installed largely below the axis of the pivot shaft 104 and roller bearings, further reducing the length of the stem required to house the suspension mechanism.

[0058] The embodiment described herein can utilize elastomer-based spring elements for both the main elastomer springs and the rebound elastomer. Other spring types, including, but not limited to, coil springs, leaf springs, magnetic springs, and air springs, may be used in lieu of elastomer springs. In the disclosed embodiments, there can be two separate compression springs that may be installed within a stem. Combining different combinations of elastomer durometers may allow the user to tune the stiffness of the suspension stem systems according to their preferences. Each elastomer can be roughly a rectangular prism shape, with a small protrusion on the front of each elastomer, such as a small protrusion 307A on elastomer 307, illustrated in FIGs. 8A-B, they can be lightly pressed into a matching cavity 308C on the rear of the preload insert 308. This may allow the elastomers 307 to be pre-installed into the preload insert 308, facilitating installation and removal of the elastomers 307 from the interior of the stem tube 302.

[0059] In the embodiment of a preload insert, illustrated in FIGs. 8A-B, there may be sides of the elastomer springs that may have a concave shape 307B, which can allow them to expand laterally as they are compressed. The degree of concavity can be used to tune the effective stiffness of the elastomer springs, and may also define a “solid” height, where the internal space within the various embodiments of stem tubes has a cavity that can be completely filled by elastomer material, at which point the effective spring rate increases dramatically.

[0060] While embodiments of the disclosed improvements have been illustrated and described, it will also be apparent that various modifications can be made without departing from the scope of the invention. It is also contemplated that various combinations or sub-combinations of the specific features and aspects of the disclosed embodiments can be combined with, or substituted for, one another in order to form varying modes of the embodiments. Accordingly, it is not intended that the disclosed improvements be limited, except as by the appended claims. Any references cited within are herein incorporated by reference in their entirety.

Claims

AMENDED CLAIMS received by the International Bureau on 14 November 2025 (14.11.2025)

1. A suspension stem comprising: a steerer-tube clamp comprising at least one transverse bore, wherein the steerer-tube clamp is structured and configured to attach to a steerer tube; a stem tube connected to the steerer-tube clamp near a first end of the stem tube, the stem tube comprising at least one stem-tube bore that is aligned with the transverse bore, and a cylindrical handlebar cutout on a second end of the stem tube; at least one pivot shaft structured and configured to allow the stem tube to vertically pivot relative to the steerer-tube clamp and about the aligned transverse bore and stem-tube bore; a face plate configured to attach to the second end of the stem tube; at least one elastic element disposed within the stem tube; and a preload insert at least partially disposed within the stem tube between the at least one elastic element and the face plate, wherein the preload insert comprises a front surface that protrudes beyond the cylindrical handlebar cutout.

2. The suspension stem of claim 1 in combination with a bicycle handlebar, wherein the preload insert is disposed between the secured handlebar and the at least one elastic element, the at least one elastic element is compressed by the preload insert, and the preload insert is in contact with the bicycle handlebar such that a rear surface of the preload insert provides the compression on the elastic element, and the front surface of the preload insert is tangent with the cylindrical handlebar cutout.

3. The suspension stem and bicycle handlebar of claim 2, wherein the at least one elastic element is structured and configured to pivot the stem tube upward in the vertical pivotalrange and resist downward movement in the vertical pivotal range.

4. The suspension stem of claim 1 , further comprising a reboundelastic element that is disposed within the stem tube, the rebound-elastic element being located between the handlebar and the steerer-tube clamp.

5. The suspension stem of claim 1 , wherein the faceplate is attached to the stem tube with at least two faceplate bolts and configured to hold the handlebar in a fixed position.

6. The suspension stem of claim 1 , further comprising a back stop that is disposed between the steerer-tube clamp and the at least one elastic element.

7. The suspension stem of claim 1 , further comprising at least one bearing wherein the at least one bearing is disposed within the transverse bore, and / or the at least one bearing is disposed within each stem-tube bore.

8. The suspension stem of claim 7, wherein each bearing is secured via an interference press fit, and wherein each pivot shaft is secured via an interference press fit into each bearing.

9. The suspension stem of claim 8, wherein each bearing is a roller bearing, and further wherein the pivot shaft is an interference fit directly through rollers of the roller bearing.

10. The suspension stem of claim 4, wherein the steerer-tube clamp includes a protrusion that houses the transverse bore, and wherein the rebound-elastic element is disposed between the protrusion and the preload insert.

11. A suspension stem comprising: a steerer-tube clamp structured and configured to attach to a steerer tube, wherein the steerer-tube clamp has a front side and a rear side; at least one pivot shaft disposed within the steerer-tube clamp, wherein the pivot shaft is structured and configured to allow a stem tube to vertically pivot; the stem tube disposed on the front side of the steerer-tube clamp, wherein a front of the stem tube has a cylindrical cutout;a preload insert positioned at least partially within the stem tube, wherein the preload insert comprises a front surface that protrudes beyond the cylindrical handlebar cutout; and an elastic element, wherein the elastic element is disposed within the stem tube, between the preload insert and the steerer-tube clamp.

12. The suspension stem of claim 11 , further comprising a rebound-elastic element that is disposed within the stem tube, between the handlebar and the steerer-tube clamp.

13. The suspension stem of claim 11 , further comprising a faceplate that is removably disposed on the stem tube, wherein the faceplate is attached to the stem tube with at least two faceplate bolts.

14. The suspension stem of claim 11 , further comprising a back stop that is disposed between the steerer-tube clamp and the at least one elastic element.

15. The suspension stem of claim 11 , further comprising at least one transverse bore in the steerer tube clamp; at least one stem tube bore in the stem tube for the at least one pivot shaft; and at least one bearing, wherein the at least one bearing is disposed within the transverse bore, and / or the at least one bearing is disposed within the at least one stem-tube bore in the stem tube.

16. The suspension stem of claim 15, wherein each bearing is secured via an interference press fit, and wherein each pivot shaft is secured via an interference press fit into each bearing.

17. The suspension stem of claim 15, wherein the steerer-tube clamp includes a protrusion that houses the transverse bore, and wherein a rebound-elastic element is disposed between the protrusion and the preload insert.

18. The suspension stem of claim 11 in combination with a bicycle handlebar, wherein the preload insert is disposed between the secured handlebar and the at least one elastic element, the at least one elastic element is compressed by the preload insert, andthe preload insert is in contact with the bicycle handlebar such that a rear surface of the preload insert provides the compression on the elastic element, and the front surface of the preload insert is tangent with the cylindrical handlebar cutout.

19. The suspension stem of claim 15, wherein each bearing is a roller bearing, and further wherein the pivot shaft is an interference fit directly through rollers of the roller bearing.

20. The suspension stem of claim 1 , wherein the at least one elastic element is in contact with the steerer tube clamp; and the preload insert is in contact with the at least one elastic element.

21. The suspension stem of claim 11 , wherein the elastic element is in contact with the preload insert and the steerer tube clamp.

Images