The Tacx Direct Drive QR Adapter Set isperfect for when you want to put a racing bike with disc brakes or a mountain bike with axle skewer in a Tacx direct drive trainer. Both axles are supplied with an adapter set so you can select the right combination for your bike. These axles are only suitable for the Tacx direct drives. Other axles are available for the classic trainers, and replace the standard axle skewer.Direct drive quick release with adapter set 135 x 10 mm - suitable for bikes with axle skewer attachment 135 x 10 mm.