The 5x11x4 Avid Clutch Bearing Set is designed to withstand all of the torture you throw at them. We decided to stop trying to find a happy medium of a single bearing to cover both clutches and wheels. Clutch temperatures easily reach three (3) times more than that of a wheel bearing. In order to make this bearing more suitable for high temps and insane loads, several things had to be adjusted. First, the balls are 20% larger than our standard $1 bearing. Second, the depth of the grooves is much deeper so that there is a massive increase in the surface area for the larger balls. Third, the grooves are polished more than our standard bearing for a smoother surface which ensures the balls have the least amount of friction when experiencing those high loads. Lastly, the metal ribbon cage is replaced with nylon like our Aura and Engine Bearings which are 9-time IFMAR World Champions. This removes the metal to metal drag during high heat expansion.