Over intlated tires - how much do you do?

[brucey]

Ha I forgot about truck tires being rated so much higher. My tires at 51 psi feel like a solid brick. You can take them off and bounce them like a basketball!

[redpoint5]

Originally Posted by Big Dave

I run 25% over on my truck, but these are Firestones.

This reminds me of my truck tire situation. My original tires were narrow (235mm) but had a sidewall rating of 80psi. I bought some all terrain tires because I was tired of getting stuck in wet grass, and decided to go fatter and taller (285mm). The new tires have a sidewall rating of only 50psi I believe.

Do wider tires not need such high pressure since the weight is distributed over a larger contact area?

Originally Posted by brucey

Ha I forgot about truck tires being rated so much higher. My tires at 51 psi feel like a solid brick. You can take them off and bounce them like a basketball!

Yeah, I normally drive with nothing weighing the bed down, and running over 40psi makes for a stiff and bumpy ride. I got used to it though. Tonight I'll find out what pressure I'm currently running and consider bumping it up.

[rmay635703]

My Buick lesabre I ran 50-60PSI year round in 35psi tires, I had roughly 40000 miles on them and they were still in good shape (cheap tires too)

My cobalt being new I keep at or slightly below the rated sidewall most of the time with the rear up to 52psi in a 44psi tire, front I keep at or below.

Cheers
Ryan

[Sulfuric]

I run about 65 on my Bridgestone Ep100, sidewall is 44. BTW tire burst pressure is well over 100psi for undamaged quality tires. The only difference is comfort and possibly higher chances for tire damage is you hit a nail or something bad.

[slowmover]

You bring up many good points. I do keep the front and rear pressure differential the same for safety and handling reasons. This is funny because I acknowledge that over-inflating tires will cause longer braking distances, increased rollover tendency and create a stiffer ride, and yet I still do it.

An SUV, a pickup are already burdened by a high center of gravity. The Ford Exploder fiasco showed what a problem that is when pressure and load are not matched. "Low" factory pressure isn't about soft ride it is about many qualities. The quality of the best tire, along with sane pressures, is the way to go, IMO.

The trucking industry -- and NO ONE knows more -- will be the first to tell you that tires last longest when inflated properly. So the question about "economy" has to do with replacement costs. If I overinflate my tires but can only travel 80k on them I've not only lost money but I know that I also have made the ride, the handling, the braking, etc, all worse.

I find this to be an easier way to look at it. The small percentage increase can be found elsewhere without terrible offsetting penalties.

In the end, the very best tire is the cheapest (life, performance, reliability) but only when used properly.

[star_deceiver]

40psi (44max) in the firestone winterforce.

[mcrews]

I run 39psi nitro all the way around on Kuhmo asx 255/45/18. there is not much sidewall on 45s so I keep below 40psi.
however, on my variuos trips to Texas, I get 46psi nitro.

[JacobAziza]

Most of my experience is from bicycles, so it may not be a direct comparison. It may not be relevant at all.

Running any less than rated sidewall pressure (on a bike) gets you a slight decrease in ride bumpiness (slight enough to be irrelevant if you have suspension) at the cost of not only more rolling resistance, but also noticeably worse handling.
This is because if the tire isn't stiff, it flexes a little in the corners.
Further, unless traveling on loose dirt or mud or snow, having low pressure does exactly zero for traction and braking.
I consider the number on the sidewall to be THE recommended pressure, not the maximum.

I don't remember who it was, or what the post topic was, but somebody on this forum once claimed that high tire pressure does not in fact adversely affect braking distance (on a smooth dry surface) as is commonly assumed.

AFAIK the biggest reason not to exceed the sidewall max is that the tire and/or rim is only so strong, and if you go over by enough it can literally explode. For the purpose of avoiding lawsuits, the manufacturer picks a number well under the actual maximum a rim/tire can handle.

Not that I ever drive at the limits of the tire's ability, but I haven't found running high to have any adverse affect on braking or handling or tire wear on my motorcycle or truck.
I run the truck at 85-90 (rated at 80)

[JacobAziza]

Originally Posted by redpoint5

Do wider tires not need such high pressure since the weight is distributed over a larger contact area?

That is exactly correct

[ecoTruck]

I tried running my tires at 50psi but found the ride really rough and that the decrease in traction was not worth the possible increase in mileage. My tires are load range E and have a max rating of 80psi but i cant imagine running them that hard just to pick up a small increase in mpg. At 50psi the rear end of my truck would slide out taking corners at moderate speed on wet roads, just dropping the pressure to 40 psi allows me to carry a lot more momentum in corners(probably saves more fuel than having hard tires and cornering slower) and there was no noticeable decrease in mpg going from 50psi down to 40psi.
I'm wondering how all of you that run your tires at such high pressures can drive safely in the rain, have fun avoiding an accident with over inflated tires on your car...