Tire Pressure (1 Viewer)

[Chris_Geiger]

Personally I run my tires at the max pressure when on the street. I have found this gets the best gas milage and longest tire life.

I run my BFG's at the full 50 PSI

The lower the pressure, the greater the heat build up in the tire. A low tire will actually get much hotter than a full tire. This heat is really hard on tires and tread life.

 

[IdahoDoug]

You'll end up wearing the centers WAY disproportionately. Once the centers have quickly worn down, then the edges will come back in contact with the ground and you'll have tires that easily steer themselves on uneven pavement or bumps - called "tramlining" and "bumpsteer" respectively. In addition, once the shoulders come back in contact with the ground, you'll have sacrificed some of the tire's water evacuation ability prematurely (shallow tread in center where most of weight is carried) and MPG will drop. Other stuff that may bore the masses also happens. Basically, you can't really win with that strategy, and while you're doing it, you're also beating up suspension bushings, bearings and other stuff whose life was predicated upon peak force spikes of a certain size that you've now perhaps doubled.

Doug

 

[Chris_Geiger]

If you run the correct size tire/wheel combo, it's simply not a problem. The technobabble totally runs counter to what I have seen over and over again. Higher pressures = better handeling, milage and tire wear. You also completly missed the point about tire tempreture. Higher pressures = lower running temp, this greatly increases tire life.

The only time I see tire center wear is when running too wide of tire for a given wheel.

Your statement that lower tire pressure results in higher mileage tells me you really have no idea what your talking about.

Measuring my tires confirms I am getting flat tire wear.

 

[IdahoDoug]

Whoa Chris. Getting a bit strong by writing that I "don't really know what I'm talking about" in my opinion. I've spent my share of time working at GM's Proving Grounds evaluating tire/road interfaces with millions of dollars worth of gear. What you refer to as technobabble, we refer to as science backed by thousands of carefully observed test events. What you refer to as your personal observations, we refer to as a nonscientific observation by a sample of 1.

I also don't see where I stated that lower pressures equals higher MPG. Your higher MPG from overinflation will drop some when the remainder of the tire comes in contact with the ground and the different height tread blocks cause tread squirm with each rotation (heat, energy loss).

I won't pretend to be offended cause I've got thick skin, so no big deal. But I'm here to tell you that proper inflation creates a combination of the common tire variables of traction, handling, wear, and efficiency. Over or under inflation bring problems to the party, giving rise to the classic statement "There's no free lunch". Your overinflation improves a bit in one direction, but at costs in the others. My point is that you may not realize those costs and I was pointing them out to you.


Doug

 

[bkgiii]

I ran the Michelin LTXs @ 'overinflated' pressure(s), and while I noticed slightly (VERY slightly) increased MPG and better 'feeling' handling, I also experienced premature center tire wear. I now run 40-42 cold in the Goodyears, which are two sizes wider / one taller, and after 60k miles on them I'm seven even, expected wear with little degradation in handling / mileage. I also notice a 3PSI increase when remeasuring them 'hot'.

 

[scottm]

[quote author=Chris Geiger link=board=2;threadid=6811;start=msg56873#msg56873 date=1067492960]
Personally I run my tires at the max pressure when on the street. I have found this gets the best gas milage and longest tire life.

I run my BFG's at the full 50 PSI

The lower the pressure, the greater the heat build up in the tire. A low tire will actually get much hotter than a full tire. This heat is really hard on tires and tread life.
[/quote]

Don't you find it odd that tire makers, car makers, and race teams have spent millions, possibly billions, optimizing pnuematic tires since they were invented, and none of them have reached that conclusion? Max means the most the tire can handle at max weight for new, undamaged tires. Optimum is what the car maker should be recommending, based on a lot of science and testing.

 

[Chris_Geiger]

Remember the Ford explorer tire failures and roll overs. These were partially caused by Ford recommending a lower tire pressure than Firestone. Later Ford raised it's tire inflation recommendations as a result. Lower pressures are used by manufactures for ride comfort. It's a common practice for used car salesmen to drop the pressure in tires so the ride seems more comfortable.

I get plenty of outside tire wear from driving off road with very low pressures.

FYI the top dogs at BFG recommend running at or near max inflation on heavy rigs. The LC is no lightweight. I keep mine as light as possible but it's still nearly 6000 lbs.

I took my first automotive suspension class in collage 25 years ago. This is where I learned to read tires and interpret suspension issues based on wear patterns. I know what your saying about center wear, I just don't see it happening.

 

[cary]

Idaho Doug obviously knows a great deal about tires. I know a bit from reading and road race experience and it is very apparent that he is not bullshixxing. Setting your pressures at the max does not automatically mean the lowest tempurature and longest life. In fact it is the opposite. When you are dialing in a race car, one thing you do to establish the proper pressure is measure tempurature across the tire face to establish overinflation or under (camber will also play into this) When the tire is hotter on the permiters than the center, it is underinflated. When it is hotter in the center of the tread, it is overinflated.

Saying you should just put the tires at the max, is like saying 1) just advance the timing all the way, 2) crank up the boost on that turbo, if a little is good, a lot is better, 3) if 10w-30 oil is to thin than 25w-70 must be better. That said, I would rather people drive with their tires set at max pressure than never checked and at 15 pounds.


Cary

 

[ginericLC]

[quote author=Outback link=board=2;threadid=6811;start=msg56144#msg56144 date=1067369336]
ginericfj80,

I don't agree with your statement above regarding running CO[sub]2[/sub] in your tires. CO[sub]2[/sub] has the same expansive properties as "normal air". You would NOT see an appreciable difference in running "normal air" vs. CO[sub]2[/sub]. Infact, when using CO[sub]2[/sub] regularly, you DO NOT put moisture in your tires like most service station air systems that usually don't have driers in the lines. So you won't be introducing another variable, the moisture in "normal air".

Jody.
[/quote]

Maybe that is true? I don't know. All I know is that when I use C02 my tire pressure bumps up more rapidly than normal air when going down the road. Do I have a fluke? I don't use filling station air in my tires usually and the air goes in and out so frequently (at least biweekly) I think I would become aware of a moisture problem. Also I live in a pretty dry climate, high desert which might help the amount of moisture. I regularly let the C02 out and refill with normal air to try to combat this inflation I've found. Am I doing something wrong?

 

[Gumby]

All of y'alls problem is that you're probably still running summer air after labor day. Swing it by my shop and I'll put some fresh winter air in there.

For a minimal charge, of course.

 

[landtank]

I've seen center wear in a car tire from being over inflated. That was a few years ago and it was a bias ply tire. Something like a BFG load range E tire is going to have a very stable profile throughout the iacceptable inflation range.

 

[landandsea]

[quote author=Gumby link=board=2;threadid=6811;start=msg57189#msg57189 date=1067565879]
probably still running summer air after labor day. [/quote]

Another maintenance item to add to the list...Replace air in tires every equinox and solstice.

Ed

 

[cruiserdan]

I use only pure Rocky mountain spring water... :whoops:...air......Wrong topic...