14 Speed MTB Gearbox
Start Date: June 2020
End Date: Ongoing
​
Background:
This project has been a personal project of mine for over 2 years. It has developed a lot over that time and is now nearing readiness for prototyping. The objective of this project is twofold.
1. Improve on the current MTB gearbox designs (of which there are very few) in particular in terms of engagement and shifter type.
2. Use a gearbox to solve the 2 major constraints on suspension design. Pedal kickback and unsprung mass.
​
Some aspects of this design are not shown or discussed on this page in particular the shifting mechanism and final drive output assembly. This is due to the potential for patent applications.
​
Why is a gearbox better than a traditional chain and derailleur?
​
Advantages:
-
Less unsprung mass. Traditional systems have a cassette, derailleur and freehub all on the rear axle
-
Better weight distribution. Weight at the BB is the best place for it to be.
-
Less vulnerable to impact damage than a derailleur
-
Lass vulnerable to debris and dirt causing interference
-
Less maintenance needed
-
Much less need for adjustment/tuning over its life
-
much more durable
-
Potential for shifing without pedalling
-
Potential to shift while under significant load
Disadvantages:
-
Higher total weight (probably)
-
Less efficient
-
Not compatible with most traditional frames
​
​
Shifting
​Power is transferred to the desired gearset by controlling what set of pawls is activated. The hard part is that there is not a single linear pattern of selection when moving through the gears. This makes controlling the gear selection system very demanding.
