So I'm not sure if this statement I am making is myth or fact, but IIRC, DOT ratings for tire speed and other applications, are minimum 2x safety rated, possibly 3x. So the 75mph rating at max advertised load, on average, in approved testing environments should not fail until a minimum of 150mph. Now I am certain that temperature and other variables are considered, but in lab testing under guidelines approved by DOT, the 75mph is half or less of "lab test" failure speed.? I honestly do not know, just what I remember "hearing" years back. Likely myth, but....
For no real good reason, I seem to, on average, take my steer tire conditions and pressures more seriously than the drives. IE: I tend to run them, though lower than marked on the tire, higher than what I would run for ride quality. I am lighter on the steers than most here, and much of that is because I am still tandem drive and have some weight behind the drive trunnion.