This heavy duty metal spur gear does fit the stock Traxxas center differential and is very heavy in weight, I decided to use this 53 to test a 15/53 gearing for a sensored Holmes hobbies crawler 6000kv racing motor, for 2s class racing! I like the quality, I wanted durability and this gear is surely that! Just make sure to set your gear mesh with very little lash, but spins with very little friction and doesn't bind up!