Here's an example of running small tires fast and having no problems.
When the wife and I were into MC riding I had an 06 Honda Goldwing. I built a small cargo trailer for it. I usually over build my stuff when I make things so this trailer was no exception. I used some 1500lb hubs and spindles and fabbed my own axle. I put what everyone else was using on it for tires. 4.80/4.00x8.
They were even the so called China bombs. 590lbs @60psi.
Of course we MC'ers never ran 60psi as the little cargo trailers would bounce all over. So we aired down to 25psi. The trailer weighed around IIRC 175lbs. And we had about 70lbs in it. We pulled that little trailer with under inflated China bombs all over Oregon, NorCal, Utah, Co and Idaho. Always went the speed limit and when on the interstate ran 70-75mph. Every stop for gas or potty break I always felt the tires. Funny thing is the trailer tires were always cooler than the Goldwing tires that had over 1000lbs on them and were at max psi. And you can imagine the rpms those little 8" tires were turning. We never even thought about China bombs vs USA made or brand recognition. Just ran whatever worked.
IMO its all about weight when looking for tire longevity. Load any tire to it's max and your asking for trouble. Ironically we never carried a spare for the trailer. Didn't have one for the MC so I guess we would just deal with either one if we go a flat. Here's a pic of the trailer with China bombs.
