Coming from RPM and made for the Traxxas X-Maxx monster truck are new oversized wheel axle carriers. They were designed to solve two key issues, the first being durability. RPM designed these carriers to handle some serious abuse with massive support ribs for the strongest possible carriers available. The other area of improvement comes in the form of larger inner bearings. The stock inner bearings are a mere 20x27x4mm while the oversized bearings are gigantic 20x32x7mm bearings. That equates to a dynamic load rating that is nearly 300 percent higher than the stock bearing while the static load rating is over 300 percent higher. The hub carriers come including the new inner bearings while the outer bearings are the stock Traxxas ones.