Chainring guard

thingiverse

I utilize a regular, not narrow-wide, chainring in the middle position of my triple crankset; an affordable alternative to a single drivetrain. Currently, I employ a front derailleur as a gauge of chain retention, but I still experience rubbing when shifting to either extreme gear. Instead of investing in a narrow-wide chainring, which is pricey or unavailable in my desired tooth count (40-46T) and BCD combination (96 mm), I opt for this chainring guard that replaces the largest and smallest chainrings to prevent the chain from derailing off the middle ring. This product was not designed to prevent chain derailment off the largest ring, essentially serving as a high limit screw replacement. I have created STLs for my own use in 96 and 64 mm BCDs (4-bolt) as well as a test STL in 110 mm BCD (5-bolt). The design features countersinks for standard M8 x 0.75 chainring bolts.