"Inflation pressure does not affect grip": Autospeed article.

[CapriRacer]

For now, I'll been confining my comments to Sgt. Storton's article - specifically the issue of whether or not his contention that the increase in inflation pressure increases the load carrying capacity and that this increase in inflation pressure does not cause a ballooning effect because the 2 steel belts prevent it. So I hope you'll excuse me if I ignore any other issues that might have been raised.

Originally Posted by dcb

The color distribution across the contact patch seems most uniform at the 45 psi image, to me. You don't have those peaks under the sidewalls.....

Thank you for proving my point that Sgt. Storton is incorrect. The increase in inflation pressure caused the center of the tread to increase in pressure. This is the basic principle. The only question is what is the starting point for a particular tire. This one happens to be quite good. Some are not so good.

Originally Posted by orange4boy

.............

Thank you for proving my point. Sgt Storton had based his recommendation on the increase in load carrying capacity and this says there isn't any.

BTW, I find it terribly ironic to be accused of never having provided ANY "scientific and government studies as well as textbook references", and then to have the accuser pull documentation from my own web site.

[dcb]

I don't know if anybody knows what your point is, so how can it be proven?

Lets start over, you acknowledge that increased pressure (i.e. 45psi) improves (or at least doesn't injure):
Rolling Resistance
Wear
Cornering turn in
Braking Traction
reduced hydroplaning

What is the problem again? Oh, the exact mechanism? ok, so belts are not parallel, yah, ok, still hard to shear them when they are overlaid and bonded. The tire at 45 didn't seem to get "rounder", it got less concave.

[Frank Lee]

[Christ]

I have to say I kind of agree with DCB on that last point... if the tire had gotten anything more than flat at the higher pressure, the result would have been increased pressure on the center tread, with lowered pressure on the outsides... that didn't happen?

In the other pictures, which include "recommended" pressure for a large majority of vehicles (which only applies to OE tires, AFAIK, and not any other tire, regardless of similarity to OE), still shows that the edges of the tire are under more stress, and thusly, would wear faster.

I don't think we're all looking at the same leaf on this tree, either... i.e. We're probably using our own "idea" about terminology, whether or not it's the "industry standard" for a specific term. Some of us might benefit from clarifying exactly what we mean when using potentially abstract or unknown terminology.

[orange4boy]

From Tire Rack:Tire Tech Information - Air Pressure - Correct, Underinflated and Overinflated

Disadvantages of Overinflation

An overinflated tire is stiff and unyielding and the size of its footprint in contact with the road is reduced. If a vehicle's tires are overinflated by 6 psi, they could be damaged more easily when encountering potholes or debris in the road, as well as experience irregular tread wear. Higher inflated tires cannot isolate road irregularities as well causing the vehicle to ride harsher and transmit more noise into its interior. However, higher inflation pressures reduce rolling resistance slightly and typically provide a slight improvement in steering response and cornering stability. This is why participants who use street tires in autocrosses, track events and road races run higher than normal inflation pressures.

I agree that over inflation may wear out the centre of the tread faster. I personally doubt that max sidewall would do that. Why would a tire company who's warranted tires will be installed on many different cars with different recommended pressures build a tire that would wear out prematurely when pumped to the max sidewall? In my own experience I have always run max sidewall and never had the centres wear out faster than the edges. I have had my edges wear out faster from cornering fast though.

[dcb]

here is a visual on tire construction

[CapriRacer]

Originally Posted by Christ

....... if the tire had gotten anything more than flat at the higher pressure, the result would have been increased pressure on the center tread, with lowered pressure on the outsides... that didn't happen?.........

Perhaps it would help if I posted another footprint:



Please note that this tire is inflated to 44 psi.

[gone-ot]

...at highway speeds, due to centripedal force, that's the "foot print" one should expect to see, because of the manner in which the tire face contacts the pavement and then compresses (typically about 3% of total diameter) somewhat.

...a "perfectly" square tire "foot print" implies no movement.

[TheEnemy]

Let me see if I get this straight,

You guys are aguing about whether or not overinflation increases or decreases traction when the quality of the tire in the first place is going to have more of an effect.

[moorecomp]

Probably not the best example to use a Wrangler HT, Google it and see how many have experienced severe issues with this tire.