Variable-Jump Cogset Layout for Mixed-Terrain Gear Progression
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Solution Overview
Problem
Existing 'gravel' cogsets fail to adequately meet the diverse requirements of demanding cyclists in mixed terrain conditions, as they struggle to balance the need for both high-speed gear ratios on level roads and high-torque gear ratios on irregular surfaces.
Innovation Solution
A cogset design featuring multiple sprockets arranged in subsets with varying 'jumps' between sprockets, providing at least five long gear ratios for regular roads and a gradual transition to short gear ratios, with the first subset having a consistent jump of 1 and the second subset increasing by 1 between each sprocket, optimizing gear shifting across different terrain types.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a cogset combines both very small sprockets and very large sprockets in the same set, then it can provide both long gear ratios for road use and short gear ratios for off-road use, but it fails to adequately satisfy the multiple requirements of demanding cyclists in mixed terrain conditions
Solution Approach 1:
The cogset is divided into multiple subsets of sprockets, each subset having a specific jump pattern. The first subset has a jump of 1 between consecutive sprockets, while the second subset has a jump of 2, and the third subset has a jump of 3. This segmentation allows different regions of the cogset to serve different functions: the first subset provides fine-grained gear ratios for road conditions, while the second and third subsets provide coarser gear ratios for off-road conditions, thereby resolving the contradiction between versatility and reliability.
Solution Approach 2:
Different subsets of sprockets are assigned different jump characteristics to optimize performance for specific terrain types. The first subset with jump=1 is optimized for road use where small incremental changes are needed, while the second subset with jump=2 and third subset with jump=3 are optimized for off-road use where larger gear ratio changes are beneficial. This local differentiation of properties allows the cogset to reliably meet the specific requirements of demanding cyclists in various terrain conditions.
2Speed
If a cogset uses very small sprockets for road use, then long gear ratios are achieved for high speeds, but the ability to develop high torque at low speed is reduced
Solution Approach 1:
The cogset segments sprockets into different subsets based on their suitability for speed versus torque. The first subset with smaller sprockets and jump=1 is dedicated to high-speed road conditions, while the second and third subsets with larger sprockets and higher jumps are dedicated to high-torque off-road conditions. This segmentation allows cyclists to select appropriate sprockets for their specific needs without compromise.
Solution Approach 2:
The cogset utilizes parameter changes in sprocket size and jump values to transition between speed-optimized and torque-optimized configurations. By varying the primitive circumference of sprockets across different subsets and changing the jump patterns (from 1 to 2 to 3), the system enables cyclists to achieve both high-speed capability and high-torque development by selecting from the appropriate subset of sprockets.
3Force
If a cogset uses very large sprockets for off-road use, then short gear ratios are achieved for high torque at low speed, but the ability to achieve high speeds is reduced
Solution Approach 1:
The cogset segments sprockets into different subsets where the second subset with larger sprockets and jump=2, and the third subset with even larger sprockets and jump=3, are optimized for torque development in off-road conditions. Meanwhile, the first subset with smaller sprockets remains available for high-speed road sections, allowing cyclists to maintain high speed capability while having access to torque-optimized sprockets when needed.
4Adaptability or versatility
If a cogset provides a wide range of gear ratios for mixed terrain, then adaptability to different conditions is improved, but the complexity of the cogset structure increases
Solution Approach 1:
The cogset is segmented into three distinct subsets with clear jump patterns (1, 2, and 3 respectively), which organizes the complexity in a systematic way. This segmentation makes the wide range of gear ratios more manageable and easier to navigate than a random assortment of sprockets would be, thereby reducing the perceived complexity while maintaining high adaptability.
Solution Approach 2:
The systematic variation of jump parameters (1, 2, 3) across subsets creates a structured progression in gear ratios. This parameter-based organization allows for a wide range of ratios to be achieved through a predictable pattern, making the cogset easier to use and understand despite the diversity of options available for mixed terrain conditions.
Data Source
AI summary
A cogset having a plurality of axially adjacent sprockets between a first sprocket with a minimum primitive circumference and a last sprocket with a maximum primitive circumference and the primitive circumferences are expressed as an integer dimensionless value equal to the ratio between the primitive circumference itself and a fixed length equal to a chain pitch. The difference in value between the primitive circumference of the sprocket next to a predetermined sprocket and the primitive circumference of the predetermined sprocket is defined as the jump associated with the predetermined sprocket. A first sprocket subset comprises the first sprocket and at least the next three sprockets and a second sprocket subset comprises at least three adjacent sprockets that do not include the first sprocket. The jump associated with all of the sprockets of the first subset is equal to 1, whereas the jump associated with the sprockets of the second subset increases by 1 from one sprocket to the next.