Rear Thru Axles.With the increasing use of UDH, we felt it was time to create rear thru axles.To start, we will have rear axle combinations for select UDH-compatible frames from Santa Crux, Specialized, Trek, and Transition.Features:Cutout to reduce weight and maintain optimal bearing support for Hope hubs.Allen wrench mount on all rear axles in case of a disaster.UDH-compatible bolts available separately to match the axles.The drive bolt is not compatible with a GX drivetrain derailleur.it only works with XO or XX.Available in all 7 Hope colors.Rear axle combinations for Santa Cruz, Specialized, Trek, and Transition.Designed, tested, and manufactured in our Barnoldswick factory.