I bought a pack of 10 rear bearings to carry in the spares. My son was breaking one every other weekend when he first started. I noticed that it often came from side slapping the wall in the sweeper at the end of the straight. So I started putting an o-ring between the stack of 1/4" axle spacers on the left rear of the car. If your car has enough space on the right side, you could do that as well. He can now make it a whole season or more on one set.