Thule Criterium provides rack level dial-activated clamp, push button clamp release, and sleek sculpted wheel tray. Xadapt8 required when used on Aero bar. FEATURES: Easy bike loading: sculpted wheel tray and support arm clamp work together and help keep bike in position when securing to carrier. Simple to use rack level adjustment dial closes clamp around bike tube for ultimate transport stability. Unloading the bike is a breeze with fast, push button clamp release. Low profile wheel tray and dual action wheel strap fits all tire sizes without the need for a wheel adaptor. Accommodates bike frames up to 3 3/8 in diameter. Fits Thule and Yakima load bars. Please call us toll free at (800)690-5220 or click the following link to see what Thule Rack and Fit Kit you need to RACK YOUR CAR. Shipping Premium Applies: An oversize shipping charge of $20 is applied to this item. This charge is in addition to normal shipping fees.