Bike Shifter Pull-Ratio Adapter Pulley
A print-in-place stepped cable pulley that converts shifter cable pull to a different derailleur pull ratio — 1.48:1 (Ø37.2 mm groove in, Ø25.2 mm groove out, or reversed for 0.68:1) so a road brifter can run an MTB derailleur. The pulley spins captive on an integral Ø8 mm axle with a 0.5 mm radial and 0.4 mm vertical clearance; each cable exits a rim notch and is pinched under an M3 screw self-tapped into a 2.6 mm hole. The 72 x 44 x 24 mm base bolts to an M5 bottle boss (5.5 mm clearance hole) or straps to a frame tube through two 8 x 2.5 mm zip-tie slots.
mechanism bicycle derailleur pulley