Tire pressure?

[Blazr]

I've been a lurker on this site for awhile and have picked up some very useful information. I have a '96 Chevy Blazer (V6) that is rated at 17/21 mpg. After trying some of your techniques; mainly more conservative driving and going 58-60 on the highway, I have been able to increase my highway mileage to a best of 28.9 mpg. Future mods call for an upper grill block, air dam and tire spats. I do have a question regarding tire pressure. I understand that by increasing tire pressure you are going to lower rolling resistance but won't the tires wear out sooner; especially in the center of the tread? If the tires wear out sooner, the gas money that has been saved won't stay in my pocket, it will have to go toward a new set of tires. So, the question is how much you can increase tire pressure without adversely effecting tire life? The sticker on my car calls for 32 psi.

[Frank Lee]

I figure a zone from max sidewall to 50 psi should cover most situations nicely. Experiment with different pressures to see how much ride harshness you can live with. Over 50 psi I think delivers little in the way of reduced r.r. but gets you into the territory where strange wear can happen. I'm talking about passenger car tires, not truck tires or other tires that are designed to operate at more than 50 psi.

[JRMichler]

I've been running my tires at 50 PSI. Max sidewall is 47 PSI. They wore on the insides of the fronts when the front end got out of alignment. The rears are wearing evenly.

And yes, I know I'm supposed to rotate them. But, if I rotated them, how would I know the front end was out of alignment?

[Frank Lee]

I don't rotate tires anymore and am just as well off because of it.

[Ryland]

If you have a set of Bias Ply tires from the 1970's then you are correct, you will wear the center out faster, but if you have those new radial tires that have been all of the rage for the last 30 to 40 years then you should be just fine with higher pressure, the sticker on the door tends to give the pressure that gives the best ride comfort without being so soft that they put you in danger of side wall blow out and that is caused by low tire pressure allowing the tire to flex so much that it over heats, the rubber brakes down and the tires side wall gives out.
A while back even AAA published something saying that there wasn't any risk in higher tire pressure as long as you stayed within the design limits of the tire.

[chrisoverson]

Originally Posted by Ryland

A while back even AAA published something saying that there wasn't any risk in higher tire pressure as long as you stayed within the design limits of the tire.

What about issues with stopping distances etc?

[Frank Lee]

Don't drive at 9/10ths and it isn't an issue 99% of the time right?

[hawk2100n]

Originally Posted by chrisoverson

What about issues with stopping distances etc?

It depends on the tire. Ride comfort was mentioned before and that's a big part of it. Tires are far superior than they were back in the day and are much less sensitive to changes in pressure. But I wouldn't recommend going much over 10% over your maximum sidewall pressure. Definitely not 50 psi. Overinflated tires can still be victims of uneven wear but it is a problem with wider tires that require the steel belts in them to be flatter than the little donuts that most people like to run on this site. My little 175/70r13s are not very susceptible to that where a 255 in a truck tire will be able to bow out in the center easier. Keep them inflated but not too high. Don't ever let them get low. That's free gas you're wasting.

[Ryland]

I'm sure if you search the arcives you will find it, but there was a study done that found that the higher pressure improved stopping at least on wet pavement because the harder tire displaced water better then a soft tire, the smaller contact area also meant that it wasn't trying to displace water from as large of an area.
A lot of snow tires are rated for 51psi, my summer tires are rated for 44psi and when I bought my car 30,000 miles ago it had 44psi in the tires and I've kept them that way, they are nearing the end of their life and the wear is dead even.

[CapriRacer]

One of the problems is that no one has done a thorough test. There's only been anecdotal information and that is what there is to work with - and there have been reports of wet traction issues and tires wearing in the center. So there is a risk. You'll have to decide for yourself if the risk is too large.