SHIMANO R ALLOY CLINCHER 24MM WH-R501-A All black alloy rims and hubs with stainless steel spokes 20-front, 24-rear spokes Radial lace front, cross-lace rear SHIMANO quality proven angular contact bearings Rim wear indicator allows safe detection of worn rim 8,9,10-speed compatible Rounded spokes (WH-R501) Aero bladed spokes (WH-R501-A, WH-R501-30) For triathlon and time trial bike (WH-R501-30) Weight: 1900g (WH-R501/WH-R501-A) 2001g (WH-R501-30)