Measure bolt circle diameters (BCD) fast and accurately. Use this tool for a wide variety of 4- and 5-bolt chain ring patterns – the tool heads centre in the chain ring holes, chain ring bolts, or crank arm holes.
- Made of laser engraved anodized aluminum
- Measures both 4 and 5 BCD chain rings
- Includes a centre-to-centre distance scale and a handy reference chart that lists additional mounting pattern measurements
