RUNWELL NJS CHAINRING GAUGE

NJS CHAINRING GAUGE measures the “42mm±2mm standard” in NJS Keirin track bikes. As shown in the photo, place the V-groove of the gauge against the seat tube and check the distance to the center line in the projection (42 mm wide). If a chainring is positioned within the thick line (4 mm wide), it meets the inspection requirements.

Stainless steel hairline is used as the material. The horizontal hairline visually supports the sense of parallel and vertical during work. Burrs are removed by hand and edges are left to improve work efficiency.

Notes
*Be careful not to scratch your frame with edges of the gauge.
*This tool was made as a gauge for inspecting NJS track bikes. Please note that it cannot correctly measure some other kinds of BB shells.