My Honda uses 3 to 4 psi, My Kawasaki uses 5 to 7 psi. I go with what is on the side of the tire, not what the manual says, becaues I always use aftermarket tires with better tread patterns. The stock tires always end up on meat trailers. I've been riding ATVs daily for over 20 years, have never popped a tire off a bead on the ATV, but I have popped them off on the meat trailer. I often load 8 to 14 hundred pounds of meat into the trailer and it uses the same tires as the ATV. Cured the problem by using an inner tube on the trailer wheels, and with the extream loads I increase the tire pressure till the tire looks like the ones on the ATV. Sometimes I have to go as high as 25psi. Yea, I know, I'm looking for an explosion.