Tire pressure difference

[guest001]

Originally Posted by theholycow

The only effect I've experienced is slight center wear. It is harmless...the center isn't bald yet when the other 90% of the tread width is down to the wear bars. More severe center wear would still be harmless in my opinion, water will still be channeled away by the non-center areas the same either way.

I've been doing this for a long time with a lot of miles on a lot of tires and that's been my experience.

you mean the center is bald and the outsides are at wear bars?

[theholycow]

No, I mean the center isn't bald when the outsides are at the wear bars.

The center reaches the wear bars when the outsides are just a hair above the wear bars; the center gets partly into the wear bars when the outsides reach them. By the time the center is bald there's barely any visible tread left on the outsides.

[trollbait]

I had the same observation on center wear.

I have had some slipping on wet pavement. It mostly when starting from a stop on an incline. I backed off on the pressure when it seemed a common occurance. Now it's likely do the tires' worn tread.

[CapriRacer]

Originally Posted by theholycow

........Impact failures and blowouts cannot be caused by overinflation. We're not talking about bicycle tires here. Impact failures happen when the impact compresses the tire until the sidewall is cut by the rim; increased pressure increases protection against that.......

That's only one of the types of impact failures - and this is more a phenomenon of low aspect ratio tires.

The other type of impact failure is when the tire encounters an object and the cords break from the force of that impact. If the inflation pressure is higher, then the tension on the cords is higher - ergo, the cords require less force to break.

[theholycow]

Interesting. Nobody's mentioned that type of failure before and I've never read about it but it sounds plausible. What about the impact causes the cords to break?

Every impact failure I've ever had (and I used to have a lot before I tried higher pressure) was snakebite-style and they did not discriminate by aspect ratio, but it's not impossible that my experience has been atypical.

[IndyFetch]

I have ran high inflation pressures in our Honda Fit since it was new. We now have almost 29,000 miles on it, and our tires probably have 20,000 miles left on them. My father-in-law has run the recommended pressures in his Fit since it was new. He replaced the tires at 33,000 miles (and I would have replaced them long before then, as they were completely bald).

*SHRUG*

[CapriRacer]

Originally Posted by theholycow

Interesting. Nobody's mentioned that type of failure before and I've never read about it but it sounds plausible. What about the impact causes the cords to break?

Every impact failure I've ever had (and I used to have a lot before I tried higher pressure) was snakebite-style and they did not discriminate by aspect ratio, but it's not impossible that my experience has been atypical.

In both impact types, the cords break because they exceed their breaking strength. In the case that is tied to low inflation pressures, the tire bottoms out and the cords are bent quite severly thereby breaking the cords.

in the other, the force of the impact itself is what breaks the cords - and obviously as the inflation pressure increases the force of impact goes up as well.

There is a photo of this type of failure here:

http://en.wikipedia.org/wiki/Blowout_(tire)

[theholycow]

That photo, embedded:


Yikes. I've never seen that kind of failure before...only sidewalls that have been cut between the road hazard and the rim and high speed low pressure sidewall blowouts. Is that common for other people?

[trollbait]

First I've seen it.
Except for once clipping a curb in what most wouldn't call a blow out, I've been lucky on that front, and some nasty potholes can appear in PA roads. One, on higher pressures, threw the Ranger's alignment out. Including the rear wheel's by a smidge (noticable on the report, but still in spec).

[tradosaurus]

That would still be covered under Discount Tire warranty.