Built to be the ultimate long distance road tire. Soft rubber compound on the front for added grip and safety. Special wear resistant rubber mix on the rear for efficiency and durability. 25mm width front and rear for a smooth ride, plus high density anti puncture reinforcement. MichelinR Pro OptimumMichelin has developed separate front and rear tires to take into account their specific requirements: The front tire carries 30% of the weight load and absorbs 100% of the braking effect. For this reason, Michelin engineers made it a priority to develop a tire with added grip, capable of providing maximum safety to users on cold, wet surfaces. The rear tire carries 70% of the weight load and absorbs 100% of the torque generated by the bike's forward motion, which affects its efficiency and wearlife. In order to achieve consistent performance, the rear tire now has a longer life, meaning that MICHELIN Pro Optimum Front and Rear tires now have comparable lifespans.