Originally Posted by inconceivable

For those running 21.5 and foam. What rollout are you using ? After digging around various threads it seems like 85mm - 90mm is the range for 21.5 F1, but wanted to verify. For testing in front of the house, I'm running the 95T spur that came with the foam ball diff and a 25T pinion which is giving me about 50mm rollout. It seems fast, but is a far cry from 85mm ? Also, if 85mm (ish) is correct, what spur have you found to be best to allow for rollout adjustment as the tires wear ? Thanks !