High air pressure in tires

[jgradyc]

Background: I have a 2000 Subaru Legacy Outback. The manual calls for 30psi front and 29psi back. The tires are Goodyear Viva 3 all season tire stamped with a 51psi max pressure rating. 

 

I routinely use 35psi for tire pressure. The reason is that I prefer a firmer ride and I can feel the sidewalls "roll" a bit taking exits on the interstate below 30psi. Can I safely go higher? Will it adversely affect handling?

[Tncobra]

You can go as high as the tire allows. You'll run into uneven wear at a certain point.

 

Over inflate and the center of the tire may wear faster, less pressure the outer may wear faster.

 

Size of tire, brand of tire and wheel size with different tires affect wear too.

 

Drive it where you have set the pressure. When you rotate look at the wear and adjust accordingly.

[Sidecarist]

My experience is that you will start to see unbalanced wear across the tread and shorten the life of the tire considerably. Also cold pressure vs hot pressure. I wouldn't be surprised to find that after a little highway driving that the pressure in the tire is as much as 5psi higher just from heat. So 30psi cold could be 35psi hot, or 35psi cold could be 40psi hot. Be consistent about how you set tire pressure. Driving to the gas station and setting the pressure at 30 (hot) your cold pressure would be several psi lower and your tires will be under inflated. The harder tire will also perform more poorly in the rain. Lastly the handling may get twitchy as pressures increase.

As to safety those pressures were selected for handling and mileage reasons. It's kind of like using handloads. You can do it but no warranty applies etc.

If you want better handling I suggest you go up in wheel size and use a lower profile tire. Tire rack has some good tools on line to help you figure that out.

[frankmako]

set it close to what is marked on the vehicle door sticker.  that psi setting will give you the best ride and tire wear.  the max psi on the tire is how much the tire can hold before blowing when in use while loaded. too much air you will wear out the center of the tire.  to little you wear out the ends/sides.  one time i pump about 10 pounds max pass the 65 pounds psi side wall number on a 20 foot trailer.  this trailer set in the pole barn and the sun got on the same/one tire each day.  two days later the tire blew out because the sun ran the psi up and the tire could not hold it.  these were new 8 ply trailer tires. the side wall blew out.  i must have jump 10 feet high when it blew.   the best time to check tire pressure is in the morning before the sun heats them up.  check on a cold tire.  also all are gauges are not the same.  i got several from high dollar for the big trucks/tractors to cheap 0.99 cent ones.  they all give a different reading.  so get close to what is call for from the owner manual and don't over think it.  also the cheaper the tire the cheaper the ride.  in tires you get what you pay for.  

[kcruisin]

I prefer to run a few lbs high, it's easier on the side-walls, and they make less heat.
The best way to check a good psi and condition of a tire, is to feel the temperature of them when you're pumping fuel during a long trip. All 4 should feel the same.
If you have a warm one or two, maybe you should find out why. If you have a hot one, don't get back on the highway without a good spare.

I have a sports car, and I thought running the max psi would give me better cornering. A tire-man took the time to correct me on that. I tried him out, and he was right. I run about 2 lbs higher than the door-post sticker.

[peejman]

As others have said, you can safely go up to the max pressure listed on the tire.  The OEM tire pressure recommendation is technically only applicable to the OEM tires.  They've done testing and analysis to determine that's the best pressure for their version of the best ride/traction/noise.  It has zip to do with mileage or wear rate since the OEM's don't provide any sort of treadwear warranty. 

 

Many newer "eco" or low rolling resistance (LRR) tires are designed to run at a much higher pressure.  You can do the "chalk test" to get a better idea of how much of the tire is actually touching the road.  When I did auto-x many years ago, it was common to put a big chalk mark from the edge of the tread half way down the side wall.  You'd make a run, look to see how much of the chalk rubbed off, and adjust air pressure accordingly. 

Edited April 29, 2016 by peejman

[1fast4by]

I have a Legacy wagon, and I have pressure set at 40psi cold.

My GMC Terrain I also run 40psi...

My wife's QX60 i also run 40 psi...

 

I have never had adverse wear

[Caster]

Go by the VEHICLE not the tire.  The vehicle is designed to run a certain pressure.  They take into account the maximum payload the vehicle is designed to carry.  Over inflation (as stated) causes the center of the tire wear more than the edges and if nothing else, it can and will make it ride like a hay wagon.  The flex of a tire is part of the vehicles total suspension and has a LOT to do with ride quality.  Been doing tires over a decade now and I can't tell you how many rough riding cars I have fixed simply by PROPER inflation.  

[1fast4by]

I understand your viewpoint, and for the most part you are correct. I have increased the pressure to sacrifice a little ride quality for fuel economy. As I have a large commute and would rather pick up where I can in fuel. I have also been in the automotive service industry for almost 2 decades. and have been an ASE master certified L1 technician for 12 years. 

[bersaguy]

I have been buying my tires at Discount Tire for many years and I can take my Jeep in about every 5000 miles and get free tire rotation and balance for life of the tires. I can also go there about any time and they will check my tire pressure and correct it to proper inflation. They keep mine at 35 PSI. I had my first flat tire in many years the other day. It was a slow leak so I inflated it and took it to them. They said it was time for rotate and balance and they fixed the flat for free. Great people to do business with...........jmho 

[glowdotGlock]

I'd go with what is on the door placard if the tires are the same size as stock. Also the max pressure rating on a tire is nowhere near where it will just blow up. Actually most tires will hold up to 300+ psi before they just explode. Crazy!

[1fast4by]

I've had plenty of customers come in well north of 100 psi... gas station Tire pumps are almost 100% of the time inaccurate by a factor of 1000

[jgradyc]

I have a Legacy wagon, and I have pressure set at 40psi cold.

My GMC Terrain I also run 40psi...

My wife's QX60 i also run 40 psi...

 

I have never had adverse wear

Thanks. I've noticed that I get tire wear on the outside with 32 lb pressure, which is another reason I've gone up to 35. Based on your experience, I may go up to 40 after I drive at 35 for a while to see what 35 feels like.

[jtmaze]

I just air them up until they are round!!!!! :devil:

[jpx2rk]

I just air them up until they are round!!!!! :devil:

 

tires are round without any air  :devil:

[wewoapsiak]

Door jamb info plate is great to use as a guide if everything is stock, other than age of the car's components and passenger weight it should be "good enough".  I do the chalk test for my truck due to loading and non-stock tires to get the ideal pressure for even wear.

[DWARREN123]

You will proabably see a degrade in braking distance also with a higher pressure and possibly a loss of some control since you are not running in the good spot for pressure

Just because the tires say 50 psig does not mean you want to run 50 psig unless they have the weigth load that needs 50 psig.

[nightrunner]

Higher pressure gives you better fuel economy.

Lower pressure gives you more traction.

A smooth ride occurs towards the lower end of pressures but not too low.

It's all about either adjusting your pressures for the task at hand or achieving a compromise that you are comfortable with.

[DaveTN]

The VEHICLE data is not always the best to go by. If the vehicle data and the tire manufacturer data are different; go by the tire manufacturer data. Some vehicle manufacturers will suggest lower pressures so they can pass roll over tests; even when the tire manufacturer advises them against it.

[1fast4by]

That's how you got the great Ford Explorer/Firestone recall. Ford was recommending 28psi in those tires, Firestone advised never to go below 32. At 28 psi the tire overheated under load and came apart. Ford was the bigger company, it wasn't going good to take the blame, Firestone did.

[DaveTN]

That's how you got the great Ford Explorer/Firestone recall. Ford was recommending 28psi in those tires, Firestone advised never to go below 32. At 28 psi the tire overheated under load and came apart. Ford was the bigger company, it wasn't going good to take the blame, Firestone did.

Bingo.

[MacGyver]

Go by the VEHICLE not the tire. The vehicle is designed to run a certain pressure. They take into account the maximum payload the vehicle is designed to carry. Over inflation (as stated) causes the center of the tire wear more than the edges and if nothing else, it can and will make it ride like a hay wagon. The flex of a tire is part of the vehicles total suspension and has a LOT to do with ride quality. Been doing tires over a decade now and I can't tell you how many rough riding cars I have fixed simply by PROPER inflation.

This guy knows what he's talking about.

[maroonandwhite]

Go by the VEHICLE not the tire. The vehicle is designed to run a certain pressure. They take into account the maximum payload the vehicle is designed to carry. Over inflation (as stated) causes the center of the tire wear more than the edges and if nothing else, it can and will make it ride like a hay wagon. The flex of a tire is part of the vehicles total suspension and has a LOT to do with ride quality. Been doing tires over a decade now and I can't tell you how many rough riding cars I have fixed simply by PROPER inflation.

So even on my truck calling for 60 in front and 80 in the back I should run that with no load? That's the max the tire will take.

[Erik88]

My tundra calls for 29 PSI which seems really low to me but I follow their instructions.

[1fast4by]

So even on my truck calling for 60 in front and 80 in the back I should run that with no load? That's the max the tire will take.

Now, with modern cars/trucks and the now required TPMS (tire pressure monitoring system) if you run under whats on the door, you get an annoying yellow light.