[N_Jay]

Originally Posted by TriKKy

I very strongly disagree that every aspect of a tire gets better with higher pressure except ride comfort.

You have the right to your opinion.
You also have the right to be wrong.

Originally Posted by TriKKy

Comfort, handling and by extension safety, predictability, resistance to blowouts (not that under-inflation is any better) all are worse.

I don't know where you list comes from, But;
Handling, predictability, and resistance to blowouts ALL get better with greater pressure.

What people seem to get hung up on are the problems with OVER-inflation (Above the sidewall rating). I am not talking about taking a tire to these levels.

Originally Posted by TriKKy

Everywhere I read indicates that over-inflation does not lead to better tire life overall. If it were the case that higher inflation is better then I would argue that vehicle and tire manufacturers would recommend it, especially given the fact that you do get better mileage from over-inflation. Car manufacturers would do just about anything to get more mileage out of their vehicles, I site the fact that they are using 5W-20 oil. If they can get better life out of the tires and better mileage why would they stick to their original recommendations if they only had to sacrifice a little ride comfort...heaven knows they aren't against giving up some ride comfort given the use of run-flats?

You are quick to make assumptions.
First, ride comfort IS very often a decision feature when buying a car. Look at the number of people who complained when dealers did not adjust the tires down from the shipping pressure of 40 PSI during the Pre-Delivery Inspection.

As for tire life, I can only go by what I know about tires and personal experience. Tire life and tire wear are directly related to the amount of flexing of the tread during use. A higher pressure reduces the amount of flexing and hence lowers internal temperatures and tread squirm. Even when rolling perfectly strait, the tread has to squirm or scrub against the pavement as the tire carcass deforms due to the weight of the vehicle. This is a significant component to tire wear.
Not to mention of the internal wear from flexing the sidewalls. Have you noticed how many "blown-out" tire you see these days with the sidewall destroyed and the tread nearly intact.
These are NOT "Blow-outs"! These are tires that were run for miles at highway speed UNDER-INFLATED. Today's radials ride so well that most drivers never notice a flat tire until it destroys itself.

As for Run-Flats, the three cars I have driven with them did not seem to suffer from ride problems. What is your experience?

My experience is that I run my '03 pilot between 36 and 40 PSI. (Usually set at 38 for normal driving and 40 for towing.) I don't run above 40 because ride comfort starts to seriously deteriorate.

I got 65,000 miles from my (crappy, as people like to call them) GY Integraties and 100,000 miles from my Michelin Cross Terrains.

Originally Posted by TriKKy

I see the numbers in the report, and I would be no means argue with data, it is what it is. The problem is that this is ideal situation data and I am not sure if the differences are significant so in ideal situations, you appear 100% correct and I was wrong in saying that distances are longer.

I think what was more interesting is that there really is very little difference.
Other than hydroplaning, where higher pressure is ALWAYS better, and some mention of tire bounce, where lower pressure is assumed to be better, I have never heard people use stopping distance as a general issue with tire pressure.

Originally Posted by TriKKy

The thing to remember however is that few roads are ideal. Over inflation by even 6psi will increase the risk of blowout as the tire has less give when shocked.

Where does this number come from?
6PSI over what? (Again, I am NOT talking about going over the sidewall rating)
I have never seen s tire "Blow-out" due to an impact. The usual failure mode is a sidewall cut due to pinching the sidewall between the tread and the rim, MORE LIKELY at lower pressures, and knocking the bead off the rim (only happens at low pressure (Typically off-road when you air-down your tires).

Originally Posted by TriKKy

Additionally, the harder/less forgiving tire will "bounce" more on uneven roads. So you are sacrificing ride comfort and secure handling. But remember, that those bounces can happen while stopping as well. If your tire isn't on the ground, it would stop as fast.

Here is where we agree. I am faily confident that unless you really like riding on hard tires you woudl not get to this range if you use ride comfort as your upper limit.

Originally Posted by TriKKy

Also, and again going back to the data, I still feel like it doesn't make sense even though it is what it is. I would like to research more. More inflation = less rolling resistance due to less tire actually touching the road surface. I would imagine that less touching would mean less friction generated by the tire meaning longer stopping distances. Perhaps the test results are a function of ABS and trying to prevent tires from fulling locking up.

Most rolling resistance is not related to the friction against the road.
It is due to energy lost heating the tires due to flexing the sidewalls and tread and scrubbing of the tread during that flexing.

While contact area goes down contact force goes up. IF you remember your middle school science experiment on friction, you will return to the same sense of amazement when you realize that the total friction stays the same.