Quote:
Originally Posted by Greenblazer
Um Ok... Well CapriRacer,
I do appreciate you responding, but it's a bit of a technical response for me to wrap my mind around. I read it through a couple of times, and I think you are saying that an overinflated tire might or will fail sooner than a properly inflated tire, but not untill it has been stressed past the failure point by lots of use. In other words a new tire might hold higher psi than printed for a while, but with age and use could fail.
Let me simplify and ask again, is it, or is it not safe to run tires at MAX sidewall PSI in your educated opinion? A simple less technical answer would be appreciated.
I don't mean to sound snarky if I am comming accross that way, text can be funny like that. I don't have the technical background to quite grasp what you are saying.
Thanks for your information and participation in this forum.
Later,
Allan Greenblazer
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You got it, he is saying that increased pressures reduce the fatigue life, but there is still a huge safety factor there. So the tread will be long gone from the tire before you get to that fatigue failure. If he simplified it in the first place he'd probably catch crap for not backing up his claims and providing technical data/charts.
As for inflating to max sidewall pressure, I think it will be a while till we have more data to support or debunk that. And I feel in the end it will come down to "sometimes", depending on the vehicle/cargo weight, tire load range (this is where where having LT tires will become more of a factor), etc.
I for one don't think max sidewall pressure is always a good idea. Like I said above, it's a "sometimes". My dad used to have a Chevy K2500 (4x4 3/4 ton work truck model). He had me take it in for new tires, they were load range E (same as what came on it stock). The tire shop decided they needed the full 85 psi called out on the sidewall. The ride was horrible. A fairly quick stop in town had the front tires audibly fighting for traction. It was really bad on a washboard road. I stopped in front of a buddy's house and layed a little rubber with a quick stab of the gas. What was revealed was two burnout's probably around 2.5 inches wide each, from 285 series tires (probably around 9" tread width).
Too much pressure + too little weight = crowned tread and very small contact patch
I had a simular experience with a stripped out Toyota pickup I had, weighed in well under 3000 lbs. Built it up with load range E Swampers becasue I had a set of free 16" wheels. Tire shop decided they needed 60 psi after mounting. A single tire's load rating was greater than what my whole truck weighed! When I aired down for wheeling there wasn't any visable buldge in the sidewall untill around 6-7 psi! A little too much tire for the truck!