The Cleveland brake system, now recommended by the factory for XL sized Velocity's. I had obtained a set from Aircraft Spruce. The 600x6 wheels and 30-52 brakes were billed as being for a Defiant and also came with two master cylinders I didn't need since the existing ones worked just fine. The Velocity factory now supplies kits that don't include the master cylinders AND also come with the custom made spacers required for a retrofit on existing psystems. The Matco axles work fine so the retrofit can be made without too much trouble. HIGHLY RECOMMENDED for XL's. Because the toe-in needed to be checked and adjusted, the following sequence of pics show disassembly of the brake and axle.