Bicycle chain wear indicator checker tool
A go/no-go chain checker for Shimano, SRAM and KMC chains that measures elongation over ten links (127 mm nominal). Two hooked ends drop between rollers: one side reads 0.5 percent wear (0.635 mm over the span) for 11 and 12 speed chains, the other 0.75 percent (0.95 mm) for 8 to 10 speed. The tool is 8 mm thick with 3 mm hooks that fit between 7.7 mm rollers, labelled in raised text, and prints flat in PETG with a 0.1 mm first layer so the reference edges are crisp.
A measured generator makes the 0.6 and 0.9 mm offsets exactly rather than relying on a file drawn in inches by someone else, and lets you add a 1 percent tab for cheap chains. Ask SpeakCAD for the wear steps you want, preview the tool free in the browser, adjust the hook width in the chat, then download the STL.
Create a bicycle chain wear checker 140 mm long, 20 mm wide and 8 mm thick with two 3 mm wide hooks on each end sized for 7.7 mm rollers, one end spanning 127.635 mm for 0.5 percent wear and the other 127.95 mm for 0.75 percent, with raised labels.