You need the traxxas X-O1 replacement hex kit. Then you need to drill out the hexes so they fit the arrma axle. Then you need to shave some material off the insides of the wheels so you have clearance for the ball joints. But it works! My recommendation: get a set of GRP Wheels, with either S5 or S7 slicks. The traxxas tires are nicer, but the GRP wheels are lighter, bolt right on - and require no modification. Its the way to go!