Custom Chainring

Vermont is a great state for mountain biking. Trails are often steep, and I find myself using the lowest end of my gearing often. To ease the effort it takes to climb, a simple solution is to decrease the size of the front “sprocket” (chainring). Unfortunately, the OEM for my drivetrain doesn’t offer smaller chainrings. There are few options aftermarket, and at the time of this project the one I wanted was out of stock.

A bit of reverse-engineering, some prototyping, and finally some machining, I had what I wanted.

I have put many miles on this initial design (multiple years of riding) and, aside from some wear, it works well. 7075 aluminum was originally chosen for strength and machinability, but I am in the process of taking the design to a hardened stainless steel. This will provide better wear resistance than any commercially available, anodized-aluminum chainring.

• Design time: 5 hours

• Manufacturing time: 4 hours