valhalla360 wrote:
theoldwizard1 wrote:
Ply rating and letter rating are "old school". DOT requires actual capacity (in pounds) be on the tire sidewall.
Yep,
Just threw in a random size (225/75R16) and came up with tires in load ranges from 104 to 121.
104 = 1,984lb
121 = 3,197lb
Both will fit on your rims and lightly loaded, won't make much difference. But guess which one is likely to do better heavily loaded?
Reality, that 104 vs 121 load index rating are probably not a heck of a lot different than a P metric vs an LR E/10 ply rated tire.
Either one of the three ratings systems basically tell you the same thing. How much a tire will carry at speeds over 25mph. stay under 25mph, you can load to 150% of sidewall capacity, or at least at one time one could do so per say.
Steel vs polyester sidewalls and treads do not give you more capacity for a given tire with the same load rating. they will be stiffer, usually a bit cooler running. SOme will last longer depending upon rubber compound.....
Marty
