Stock bearings and axle carriers aren't quite strong enough to handle the punishment T/E-Maxx owners dish out. In addition, more strength is needed at the axle carrier when offset wheels are used or when aluminum accessories and oversized wheels & tires add more weight and stress to the driveline. Once again, RPM steps in where no one else has! We have completely redesigned the axle carriers for the maximum amount of strength and durability and included some seriously beefy 15mm. bearings to top it all off!.