upanbike bike crankset with bottom bracket for road bike mountain bicycle 8 9-speed m430 crank set upanbike 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>