most truck or suv's tires say max pressure 44 psi.But as far as I know any shop will only inflate them to 35 psi, is that the average or why?
What tire pressure to run?
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The recommended tire pressure is on a tag usually inside the door. The number on the tire is the "Never Exceed Under Any Circumstances You Have Been Warned Lawyers Take Notice" pressure.
Originally Posted By: aztec12
why?
As the previous poster noted, the PSI on the tire sidewall has nothing to do with the actual PSI you should be running. Look at your vehicle placard or owner's manual to find out what the correct pressure is for the tire size that you're using.
why?
As the previous poster noted, the PSI on the tire sidewall has nothing to do with the actual PSI you should be running. Look at your vehicle placard or owner's manual to find out what the correct pressure is for the tire size that you're using.
Originally Posted By: AlienBug
The recommended tire pressure is on a tag usually inside the door. The number on the tire is the "Never Exceed Under Any Circumstances You Have Been Warned Lawyers Take Notice" pressure.
True; but there is a safety margin built in. I knew a guy that ran his tires at 10psi over max pressure; he said it got him 2mpg on the highway. (at what cost?)
That said....
I've had good results in tire wear running somewhere between max and recommended on numerous vehicles over the years. The heavier the vehicle, the higher the pressure in general.
On the Grand Cherokee, running tires at the recommended 32psi wears them quickly on the edges. The tires are rated at 44psi and running them at 40-42 gives even wear and IMO better handling, although the ride suffers somewhat.
The recommended tire pressure is on a tag usually inside the door. The number on the tire is the "Never Exceed Under Any Circumstances You Have Been Warned Lawyers Take Notice" pressure.
True; but there is a safety margin built in. I knew a guy that ran his tires at 10psi over max pressure; he said it got him 2mpg on the highway. (at what cost?)
That said....
I've had good results in tire wear running somewhere between max and recommended on numerous vehicles over the years. The heavier the vehicle, the higher the pressure in general.
On the Grand Cherokee, running tires at the recommended 32psi wears them quickly on the edges. The tires are rated at 44psi and running them at 40-42 gives even wear and IMO better handling, although the ride suffers somewhat.
There's no way I'm running 26f 29r in my Tacoma. That's what my placard says. I run 40f 38r.
On 2 vehicles I run what the door placard recommends.
Another vehicle the placard shows F/R 33/33. I'm running 35 front & 34 rear with its current tires.
I never run max pressure stated on the sidewalls.
I've known folks to run pressure on the sidewall because they think that's what it should be, but they usually are not aware of the door placard. That increases tire center wear rate and it runs harder.
Also, use a decent pressure gauge. And many of those at gas stations are not very accurate and take a beating. I carry one in each vehicle, and have a few in the garage. They all read within 1-psi. If I get another gauge, it should read like the rest, or it gets trashed if off kilter.
I have a nice size high resolution gauge that I can snap on a compressor tank. Back when I was in the military, friend in lab confirmed its accuracy. I keep it in a case. It's about 4.5" diameter. Before I got a collection of tire pressure gauges, I used it to check tank pressure, and it's tee'd to a schrader so I could check my tire pressure gauge against it.
Not long ago I checked a neighbors gauge (small Slime dial) and @ 40psi pressure, it showed just a touch under 33psi. So I tossed it hard into the trash can (he had a shocked look on his face), then I pulled out a much better gauge and gave it to him.
Another vehicle the placard shows F/R 33/33. I'm running 35 front & 34 rear with its current tires.
I never run max pressure stated on the sidewalls.
I've known folks to run pressure on the sidewall because they think that's what it should be, but they usually are not aware of the door placard. That increases tire center wear rate and it runs harder.
Also, use a decent pressure gauge. And many of those at gas stations are not very accurate and take a beating. I carry one in each vehicle, and have a few in the garage. They all read within 1-psi. If I get another gauge, it should read like the rest, or it gets trashed if off kilter.
I have a nice size high resolution gauge that I can snap on a compressor tank. Back when I was in the military, friend in lab confirmed its accuracy. I keep it in a case. It's about 4.5" diameter. Before I got a collection of tire pressure gauges, I used it to check tank pressure, and it's tee'd to a schrader so I could check my tire pressure gauge against it.
Not long ago I checked a neighbors gauge (small Slime dial) and @ 40psi pressure, it showed just a touch under 33psi. So I tossed it hard into the trash can (he had a shocked look on his face), then I pulled out a much better gauge and gave it to him.
The standard tires on my car are the Kumho KH25, which, according to tirerack get a very poor overall rating for mileage. Most say there done in under 20k miles. I run somewhat higher pressure than the placard and still have 1/2 tread at almost 41k miles. Alignments (at a race shop) twice a year and re-balancing the tires each time. Rotating every OCI. Wear is flat across all tires.
Manufacture tire inflation recommendation are a compromise of ride, tire life and SAFETY. I run my tires at recommended pressure to + 10% but, no more. Safety take a big hit when going overboard on pressure. Ed
I run my jeep at 24 psi. Any more and they wear out in the center. My ford is 45 front and rear although the tire says 65.
The Ford Transit work van has inflation monitors that trip a warning light. The re set is a PITA if you dont have the tool. It has a wireless transmitter in the valve stems. The van has to have a certain Continental tire to support 39 and 49 psi Its a 165 65 15 ,which is a decent profile. I run 70s on the cars and 75 profiles on the Rat. I prefer a soft ride. It is easier on the suspension to run stock tire and wheel configurations too.
Originally Posted By: aztec12
most truck or suv's tires say max pressure 44 psi.But as far as I know any shop will only inflate them to 35 psi, is that the average or why?
Every vehicle is required to have a sticker like this one on the Driver's side door jamb:
It tells you the wheel size, tire size and tire pressure recommended by the manufacturer for best compromise between comfort, performance, mileage and safety. These recommended pressures are the result of extensive testing by the manufacturer and are to be ignored at one's own peril.
Also note that the tire pressures are measured when the tires are "cold," i.e. after the vehicle has sat for several hours, the tires are not in the sun, and the ambient temperature is close to what will be experienced when driving.
As mentioned by others, the maximum inflation pressure embossed on the tire sidewall has nothing to do with what should be used for normal driving.
most truck or suv's tires say max pressure 44 psi.But as far as I know any shop will only inflate them to 35 psi, is that the average or why?
Every vehicle is required to have a sticker like this one on the Driver's side door jamb:
It tells you the wheel size, tire size and tire pressure recommended by the manufacturer for best compromise between comfort, performance, mileage and safety. These recommended pressures are the result of extensive testing by the manufacturer and are to be ignored at one's own peril.
Also note that the tire pressures are measured when the tires are "cold," i.e. after the vehicle has sat for several hours, the tires are not in the sun, and the ambient temperature is close to what will be experienced when driving.
As mentioned by others, the maximum inflation pressure embossed on the tire sidewall has nothing to do with what should be used for normal driving.
Sidewall pressure is for using the tire loaded to capacity at its max rated speed. If you read the manual, some will tell you to inflate to sidewall for cruising over 100mph, towing, fully loaded, etc. I believe the old Mercedes guideline was +4 for loaded and +4 for high speed.
Originally Posted By: aztec12
most truck or suv's tires say max pressure 44 psi.But as far as I know any shop will only inflate them to 35 psi, is that the average or why?
As stated above the mfgr provides a pressure suited to the OEM fitment. It may be heavily biased towards ride or handling, and is not necessarily optimum, just recommended.
Cautiously increasing the pressure a bit can really help some car/tire combos to get better steering response and cornering, and you may even eke out a bit of mileage, but I doubt it on any newer car.
most truck or suv's tires say max pressure 44 psi.But as far as I know any shop will only inflate them to 35 psi, is that the average or why?
As stated above the mfgr provides a pressure suited to the OEM fitment. It may be heavily biased towards ride or handling, and is not necessarily optimum, just recommended.
Cautiously increasing the pressure a bit can really help some car/tire combos to get better steering response and cornering, and you may even eke out a bit of mileage, but I doubt it on any newer car.
Originally Posted By: gaijinnv
Originally Posted By: aztec12
most truck or suv's tires say max pressure 44 psi.But as far as I know any shop will only inflate them to 35 psi, is that the average or why?
Every vehicle is required to have a sticker like this one on the Driver's side door jamb:
It tells you the wheel size, tire size and tire pressure recommended by the manufacturer for best compromise between comfort, performance, mileage and safety. These recommended pressures are the result of extensive testing by the manufacturer and are to be ignored at one's own peril.
Also note that the tire pressures are measured when the tires are "cold," i.e. after the vehicle has sat for several hours, the tires are not in the sun, and the ambient temperature is close to what will be experienced when driving.
As mentioned by others, the maximum inflation pressure embossed on the tire sidewall has nothing to do with what should be used for normal driving.
Really?
Aren't those pressures listed the minimum pressure required to carry the maximum weights the vehicle is rated to carry? And, you have to read the fine print on the tire's sidewall to find what the pressure number there means. It might be the max cold inflation pressure that tire should ever have, or in the case of LT tires it is the minimum pressure required to carry the max weight that tire can carry, and up to 10 psi more is OK.
There will be another sticker on the door jam, or inside the console lid, or inside the gas filler cover that gives the recommended pressures for everyday driving. For a truck these might be the same just so you don't carry a heavy load with tires inflated for a light load.
So...what pressure should we run? Start with the cold inflation pressure on that sticker. Try increasing the pressure a couple of psi at a time until you find what feels best for you. I stay real close to the sticker pressure except when I have a full pick up load (or overload) of landscape materials or building materials. Then it's up to the sidewall max only for that trip, or when towing a heavy trailer and I want the added stability of the firmer tire. I do like the feel of two or three psi more in the fronts to reduce understeer.
Originally Posted By: aztec12
most truck or suv's tires say max pressure 44 psi.But as far as I know any shop will only inflate them to 35 psi, is that the average or why?
Every vehicle is required to have a sticker like this one on the Driver's side door jamb:
It tells you the wheel size, tire size and tire pressure recommended by the manufacturer for best compromise between comfort, performance, mileage and safety. These recommended pressures are the result of extensive testing by the manufacturer and are to be ignored at one's own peril.
Also note that the tire pressures are measured when the tires are "cold," i.e. after the vehicle has sat for several hours, the tires are not in the sun, and the ambient temperature is close to what will be experienced when driving.
As mentioned by others, the maximum inflation pressure embossed on the tire sidewall has nothing to do with what should be used for normal driving.
Really?
Aren't those pressures listed the minimum pressure required to carry the maximum weights the vehicle is rated to carry? And, you have to read the fine print on the tire's sidewall to find what the pressure number there means. It might be the max cold inflation pressure that tire should ever have, or in the case of LT tires it is the minimum pressure required to carry the max weight that tire can carry, and up to 10 psi more is OK.
There will be another sticker on the door jam, or inside the console lid, or inside the gas filler cover that gives the recommended pressures for everyday driving. For a truck these might be the same just so you don't carry a heavy load with tires inflated for a light load.
So...what pressure should we run? Start with the cold inflation pressure on that sticker. Try increasing the pressure a couple of psi at a time until you find what feels best for you. I stay real close to the sticker pressure except when I have a full pick up load (or overload) of landscape materials or building materials. Then it's up to the sidewall max only for that trip, or when towing a heavy trailer and I want the added stability of the firmer tire. I do like the feel of two or three psi more in the fronts to reduce understeer.
Im recommended to set at 30, but I find 30 too low. I typically run 34-36 all around. Max at 51 psi or something on my current tires. For best comfort and ride quality, 30 psi is fine. I guess it depends on how you like the ride to be.
Originally Posted By: Ken2
So...what pressure should we run? Start with the cold inflation pressure on that sticker. Try increasing the pressure a couple of psi at a time until you find what feels best for you. I stay real close to the sticker pressure except when I have a full pick up load (or overload) of landscape materials or building materials. Then it's up to the sidewall max only for that trip, or when towing a heavy trailer and I want the added stability of the firmer tire. I do like the feel of two or three psi more in the fronts to reduce understeer.
Good advice...each tire brand/model is unique so raising the PSI by 2psi at a time is good advice for finding the optimal performance characteristics desired...between "performance" and comfort...most passenger cars' PSI recommendations (and tires/suspension) are for comfort, a nice soft ride...sportier models may differ as their tires as well as suspensions are different.
...and also....I think that THIS is backwards...that a PSI higher at the rear than in the front reduces understeer...
So...what pressure should we run? Start with the cold inflation pressure on that sticker. Try increasing the pressure a couple of psi at a time until you find what feels best for you. I stay real close to the sticker pressure except when I have a full pick up load (or overload) of landscape materials or building materials. Then it's up to the sidewall max only for that trip, or when towing a heavy trailer and I want the added stability of the firmer tire. I do like the feel of two or three psi more in the fronts to reduce understeer.
Good advice...each tire brand/model is unique so raising the PSI by 2psi at a time is good advice for finding the optimal performance characteristics desired...between "performance" and comfort...most passenger cars' PSI recommendations (and tires/suspension) are for comfort, a nice soft ride...sportier models may differ as their tires as well as suspensions are different.
...and also....I think that THIS is backwards...that a PSI higher at the rear than in the front reduces understeer...
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I don't understand why you find it funny/strange. If the tire sizes are selected appropriately to the size/weight of the vehicle, then the PSI may be similar.
Just an FYI:
On passenger car tires, the max pressure listed is NOT necessarily the pressure for the max load.
Passenger car tires are labeled differently than other tires and there are situations where the inflation pressure can be increased above the pressure for max load. This is reflected in what is listed on the sidewall.
And a word of note: There are tire manufacturers who I think label their tires incorrectly (or at least, misleadingly). So be careful about how you read the sidewall when it comes to the pressure.
Bottomline: If you are using the same size as listed on the vehicle tire placard, then the pressure listed there is appropriate. I can understand that some may feel uncomfortable if they think the pressure is too low. Note to those people: Tire size plays a sigbnificant role in load carrying capacity, so you shouldn't consider pressure without conmsidering size.
Also, a few psi is not a big deal. Personally, I like a crisper feel to a car, so I typically add 3 to 5 psi over what is listed on the vehicle tire placard.
BUT. I think more than 5 psi is NOT a good idea. That results in a smaller footprint, and therefore less traction.
On passenger car tires, the max pressure listed is NOT necessarily the pressure for the max load.
Passenger car tires are labeled differently than other tires and there are situations where the inflation pressure can be increased above the pressure for max load. This is reflected in what is listed on the sidewall.
And a word of note: There are tire manufacturers who I think label their tires incorrectly (or at least, misleadingly). So be careful about how you read the sidewall when it comes to the pressure.
Bottomline: If you are using the same size as listed on the vehicle tire placard, then the pressure listed there is appropriate. I can understand that some may feel uncomfortable if they think the pressure is too low. Note to those people: Tire size plays a sigbnificant role in load carrying capacity, so you shouldn't consider pressure without conmsidering size.
Also, a few psi is not a big deal. Personally, I like a crisper feel to a car, so I typically add 3 to 5 psi over what is listed on the vehicle tire placard.
BUT. I think more than 5 psi is NOT a good idea. That results in a smaller footprint, and therefore less traction.
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