The Perfect Racer:- Faced with the extreme challenges of today's XC tracks, we completely revised Racing Ralph. The result is a very fast and versatile XC profile, specially developed for the rear wheel.Features:- Numerous grip edges in the tread center for super traction and excellent acceleration- Distinct shoulder studs for excellent lateral grip- Good rolling properties and extremely quietSpecifications:- Size: 57-622 (29 x 2.25)- Performance: Super Ground, TLE- Compound: Addix Speed