Scorpion E-MTB RUltra Heavy Duty for Aggressive Riding The R model is our rear specific design: added traction on both pedaling and braking durability without compromising rolling performance over a mixed variety of terrain, maximized for both dry or wet conditions due to the E MTB specific SmartGRIP+ Compound. All with a new standard of rubber lifespan and casing reliability from incorporating the HyperWALL construction. Best paired with an M on front for a balanced