Are the 9R22.5 what's commonly used on school busses? I thought or a school bus donor truck but they are even wider than the p30 and the rear axles must be slow as the busses I remember as a kid moved very slowly.

Would a mid '80's Chevy 1 ton dually pickup have the same dimensions as the p30? I have a neighbor who has one and it sounds like it would be well worth it to take some measurements.