The clearance on my ‘29 scout, is less than half inch and more like btw. 3/8 and 7/16 inch. The clearance on my ‘31 scout, is more like 1/2 inch. I have travelled incident free distances on both. I am able to safely place my hand, approx. half inch away from the muffler, where I feel radiating heat, but do not get burned. Whilst underway, one must envisage, cool air force flow btw. muffler and tyre, constantly cooling both exhaust and tyre, and dissipating any problematic heat. Hope this helps. Cheers