Tue–Fri: 10am–6pm | Sat: 9am–4pm | Sun–Mon: Out riding
Runwell GAUGE42S NJS Chainring Gauge
People often ask as the best way to improve performance, we say one thing. Chain line. The distance from the center of the frame to the center of the chainring should be 42 mm ± 2 mm, depending on your configuration.
This product responds to a request to manufacture a gauge that instantly measures this chain line standard which exists in the Professional state of the Japanese Keirin.
To use this nifty tool, just place the V-groove of the gauge on the seat tube, and use the center line of the V-groove. The base measurement of 42 mm is at the center line of the protrusion and the thick line extending 2 mm to the left and right from the center line of the protrusion showing ± 2 mm. The burrs on the product are removed by hand, leaving some edges to improve workability. When measuring, be careful not to damage the seat tube with the cross section of the V groove. This gauge was made as a gauge for inspecting the body of NJS. It may not be possible to measure correctly depending on the design or seat tube and/or width of the BB shell. Manufacturing Advisor: Mr. Kenji Ishii, Maebashi Bicycle Racetrack Inspector.