Chain keeper/dummy hub/axle kit for thru axle

Chain keeper (a.k.a. dummy hub) and dummy front hub kit for thru-axle road bicycles.

This assembly is a chain keeper (also commonly referred to as a dummy hub) for 142x12mm thru-axle, which is the most common rear thru-axle standard for road bicycles. Unlike many common chain keeper designs, this design is not composed of only an idler gear that rotates around the thru-axle of the bicycle. Rather, this design has an actual “hub” that sits within the dropouts of the bicycle. There are two unique advantages to this design. The first advantage is that the design is compatible with stepped thru-axles. The second advantage is that the dummy hub can also serve a second purpose as a brace for the rear triangle of the bicycle when the rear wheel is removed. 

There are two idler gear assemblies: 10t for SRAM AXS, and 11t for Shimano 11/12s. The gear assemblies are not interchangeable, and a chain of one type will not fit on a gear assembly for the other. A standalone “hub” piece for 100x12mm thru-axle is also included. Similar to how the “hub” piece of the chain keeper assembly can be used to brace the rear triangle of the bike, this piece can be used to brace the fork of the bike when the front wheel is removed. The main application of this is when the bike is to be transported without wheels installed.

A complete kit consists of the “Axle kit” print profile, and one of the “gear kit” print profiles. The “Axle kit” print profile provides the two “hub” pieces. The “gear kit” print profiles provide the chain keeper gear assembly of the specified chain standard. The assemblies of this kit are composed of multiple parts that thread together. The tolerances are quite tight. To prevent harm to your hands and fingers, use the ring-shaped assistance tools to grip the various circular parts. The order of assembly of the parts should be self-explanatory. Refer to the pictures of the complete assembly.