Speed and blown tires
Another thought I had while driving home today again from our holiday camping trip up north. I posted about driving to fast and not surprisingly I was told I was going to fast at 68mph even though I ...
Forum Discussion
enblethen wrote:
Letter in the Aug 2017 issue says the ST tires are rated at 65. Disclaimer added that higher speeds are capable from some manufacturer's if the air pressure is increased.
seems like there are two camps on increased speed ratings on ST tires.
1) Mfg that actually certify the tire with an increased rating on the tire. Like the new goodyears with an N speed rating stamped on the tire. That means they went through the certification process for that speed rating which is much more stringent than the test for the ST 65mph rating. Goodyear does reduce load capacity at 87mph. Mine have a load index of 117/112N. about 400lbs lower capacity at 87mph.
Now IMHO towing at 87mph would is insane. But the fact that it went through more stringent certification is a good sign.
I think there are a few other mfg that also certify a higher speed rating. I've seen some, but don't recall which brands.
2) Those that give an increase speed rating with increased pressure and/or reduced load but no certified speed rating. So one doesn't know what criteria or testing was done for that higher speed rating. If they actually tested and certified to the higher rating why don't they spec the higher rating?
