Note: We recommend that the bottom bracket is initially installed by a bike shop to ensure perfect facing and fit. thank you.</br> Crank Construction: 2 pieces solid crank</br> Cassette compatability:8 speed; 9 speed</br> Chainring numbers:42-32-22T</br> Bolt Circle Diameter:104/64mm</br> Color:Black</br> Outer Chainring: Aluminum</br> Middle Chainring: Steel</br> Inner Chainring:Steel</br> Crank Arm Length:170mm</br> Bottom bracket: fits standard 68mm and 73mm shell.</br>