Topline road crankarms. These are among the lightest road crankarms ever made - including the new carbon stuff. Lighter than Campagnolo Record Carbon. Lighter than FSA Carbon. Arm length: 170mm. These were tightened on to a bottom bracket to test the fit, and then removed from the bike. No actual riding miles on these. These take a 113mm bottom bracket on a road frame. 130mm bolt circle diameter. These will fit modern road chainrings by Shimano and others (except for Campagnolo).