Weight has more to do with it than anything, other than the bearings not being packed well. FWIW I ran 4.80x8 tires on a MC trailer. Total weight was around 250lbs. I ran 70-75 all day. Tires were never hot, always cooler that the MC's tires. I packed my bearings my self so I knew they were good. Question is who made the trailer and how well the bearings are packed. If they are the cheapo china junk in there then I would replaced them with Timken's. Pack the crude out of them. And run 65-70 all day. If your loaded to the gills then maybe not.