There seems to be a misconception of what exactly constitutes an over-inflated tire. Some people call inflating their tires to 5 PSI over what's listed on the vehicle's driver's door as over-inflated. You haven't over-inflated a tire unless you've exceeded the max PSI listed on the tire's sidewall. If the tire's inflated to a level that's between what's listed on the vehicle door and what's listed on the the tire, the tire's considered to be at a safe pressure. Where you choose to keep that pressure within those parameters is completely personal preference....
The misconception of over-inflation
- Thread starter grampi
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It may be safe, but to me, if you start noticing negative side effects such as accelerated center tread wear or bone jarring ride, then your tires are overinflated, even if the PSI is still below what's listed on the sidewall.
Not true.
Let's say the tire is rated on the vehicle for 30 PSI. Sidewall rating is 44PSI.
Run the tire @ 40 PSI and you WILL wear out the center part of the tread by OVER inflation.
The weight of the vehicle, the size of the tire/rim determines the PROPER range of pressure for the tire on that vehicle.
A couple of pounds here and there will not hurt, but the max will have the tire over inflated.
Just my 3 cents. Bill
Let's say the tire is rated on the vehicle for 30 PSI. Sidewall rating is 44PSI.
Run the tire @ 40 PSI and you WILL wear out the center part of the tread by OVER inflation.
The weight of the vehicle, the size of the tire/rim determines the PROPER range of pressure for the tire on that vehicle.
A couple of pounds here and there will not hurt, but the max will have the tire over inflated.
Just my 3 cents. Bill
Over-inflation is opposite with under-inflation, which is below the manufacture recommendation can be found on driver's door or on the inside of fuel filler door or in owner manual, therefore over-inflation is any cold tire pressure above manufacture recommendation.
Originally Posted By: stockrex
I ran 40 to 44 psi for 70 k miles on michelins on my accord v6. Never had any uneven wear never rotated them.
You weren't running bias ply tires like Bill does
I ran 40 to 44 psi for 70 k miles on michelins on my accord v6. Never had any uneven wear never rotated them.
You weren't running bias ply tires like Bill does
JHZR2
Staff member
Just because the inflation pressure on the car placcard gives some number does not mean that it is the most optimal number for fuel economy, load rating, etc.
It is dumbed down American specifications, as usual, just like the extinction of oil viscosity versus temperature charts. My european cars all give different pressure ratings depending upon load and sustained speed.
The optimal pressure is the highest that will not cause abnormal wear with the owner's typical use. The placard is a good start, usually a few psi above can be done in my experience without issue. Beyond that you have to run the experiment.
It is dumbed down American specifications, as usual, just like the extinction of oil viscosity versus temperature charts. My european cars all give different pressure ratings depending upon load and sustained speed.
The optimal pressure is the highest that will not cause abnormal wear with the owner's typical use. The placard is a good start, usually a few psi above can be done in my experience without issue. Beyond that you have to run the experiment.
Modern vehicle recommendation for tire pressure are a compromise and center around safety, comfort, handling tread life. My PO is one can exceed the manufactures recommendation by about 5-10% to enhance one characteristic at the slight expense of the others.
Originally Posted By: stockrex
I ran 40 to 44 psi for 70 k miles on michelins on my accord v6. Never had any uneven wear never rotated them.
Never rotated your tires for SEVENTY THOUSAND miles on a FWD vehicle.. And they had no uneven wear?
Okay...
Bill
Originally Posted By: XS650
You weren't running bias ply tires like Bill does
Not for a few decades. Last vehicle I had bias plys was the 1978 F250.
I ran 40 to 44 psi for 70 k miles on michelins on my accord v6. Never had any uneven wear never rotated them.
Never rotated your tires for SEVENTY THOUSAND miles on a FWD vehicle.. And they had no uneven wear?
Okay...
Bill
Originally Posted By: XS650
You weren't running bias ply tires like Bill does
Not for a few decades. Last vehicle I had bias plys was the 1978 F250.
Over / under implies there is a specification, target value, nominal value, or what ever you would like to call it. Anything above that value or below that value is by definition over/under.
Whether "a little", "reasonable", or "not a concern" is the degree of over/under. To characterize something above the specification, target, or nominal value as NOT over inflation is not being accurate.
It's sort of like being pulled over for 5 mph above the speed limit. Let's face it, that's over the limit! Whether the judge levies a fine is a different story altogether.
Whether "a little", "reasonable", or "not a concern" is the degree of over/under. To characterize something above the specification, target, or nominal value as NOT over inflation is not being accurate.
It's sort of like being pulled over for 5 mph above the speed limit. Let's face it, that's over the limit! Whether the judge levies a fine is a different story altogether.
JHZR2
Staff member
Originally Posted By: Bill in Utah
Originally Posted By: stockrex
I ran 40 to 44 psi for 70 k miles on michelins on my accord v6. Never had any uneven wear never rotated them.
Never rotated your tires for SEVENTY THOUSAND miles on a FWD vehicle.. And they had no uneven wear?
Okay...
Bill
My mother has to have at least 50k on her michelin hydroedges and they have not been rotated. This is a 97 plymouth breeze, and all four look very good.
Id say they have at least 30k more life on them...
All depends upon the tire and driving characteristics...
Originally Posted By: stockrex
I ran 40 to 44 psi for 70 k miles on michelins on my accord v6. Never had any uneven wear never rotated them.
Never rotated your tires for SEVENTY THOUSAND miles on a FWD vehicle.. And they had no uneven wear?
Okay...
Bill
My mother has to have at least 50k on her michelin hydroedges and they have not been rotated. This is a 97 plymouth breeze, and all four look very good.
Id say they have at least 30k more life on them...
All depends upon the tire and driving characteristics...
I've almost always kept my tires over-inflated for several (endlessly debated) reasons. A tire at higher pressure will improve fuel economy AND will produce less heat... and in my experience, heat and underinflation are the easiest way to destroy an otherwise usable tire. Also, I've been putting used tires on my vehicles pretty regularly for the past decade or so... and they tend to lose air slowly; so overinflation buys me a little time.
I've always been told that an overinflated tire will wear more in the center, but I've never seen it myself. On every single vehicle I've owned (both fwd and rwd), the front tires have worn more on the outsides, and the rear tires have worn evenly. Never noticed any difference due to pressure except when the tire was woefully underinflated.
On the fwd vehicles I've owned, the front tires always wear MUCH more quickly. On my daily driver that I put assorted (paired) used tires on, I'll wear out easily three pairs of front tires for every pair of rear tires. I keep a good, uniform set of tires on the wife's car, so I have to rotate them now and then.
I've always been told that an overinflated tire will wear more in the center, but I've never seen it myself. On every single vehicle I've owned (both fwd and rwd), the front tires have worn more on the outsides, and the rear tires have worn evenly. Never noticed any difference due to pressure except when the tire was woefully underinflated.
On the fwd vehicles I've owned, the front tires always wear MUCH more quickly. On my daily driver that I put assorted (paired) used tires on, I'll wear out easily three pairs of front tires for every pair of rear tires. I keep a good, uniform set of tires on the wife's car, so I have to rotate them now and then.
Originally Posted By: fdcg27
By this logic, there can be no such thing as under inflation.
I have never seen a minimum inflation spec on a tire sidewall.
The tire maker has no idea how over-rated its tire is going to be. My saturn max vehicle weight is 3100 lbs but takes 195/60/15 "87" tires that hold 1201 lbs EACH at 35 PSI max inflation. Saturn thinks 26 lbs is enough for the rear axle, and the tire makers are on board. But there's no way that could apply to all (heavier) cars that might also take this tire size.
By this logic, there can be no such thing as under inflation.
I have never seen a minimum inflation spec on a tire sidewall.
The tire maker has no idea how over-rated its tire is going to be. My saturn max vehicle weight is 3100 lbs but takes 195/60/15 "87" tires that hold 1201 lbs EACH at 35 PSI max inflation. Saturn thinks 26 lbs is enough for the rear axle, and the tire makers are on board. But there's no way that could apply to all (heavier) cars that might also take this tire size.
Originally Posted By: Bill in Utah
Let's say the tire is rated on the vehicle for 30 PSI. Sidewall rating is 44PSI.
Run the tire @ 40 PSI and you WILL wear out the center part of the tread by OVER inflation.
I've done exactly this and have never had a tire wear more in the center of the tread. I've also run other tires at their max sidewall load of 35psi, when the recommended pressure was 28, and have never had excessive wear in the center of the tread. As has already been said, this would be a problem if running bias ply tires, but who does that these days?
Let's say the tire is rated on the vehicle for 30 PSI. Sidewall rating is 44PSI.
Run the tire @ 40 PSI and you WILL wear out the center part of the tread by OVER inflation.
I've done exactly this and have never had a tire wear more in the center of the tread. I've also run other tires at their max sidewall load of 35psi, when the recommended pressure was 28, and have never had excessive wear in the center of the tread. As has already been said, this would be a problem if running bias ply tires, but who does that these days?
Originally Posted By: Samilcar
Originally Posted By: Bill in Utah
Let's say the tire is rated on the vehicle for 30 PSI. Sidewall rating is 44PSI.
Run the tire @ 40 PSI and you WILL wear out the center part of the tread by OVER inflation.
I've done exactly this and have never had a tire wear more in the center of the tread. I've also run other tires at their max sidewall load of 35psi, when the recommended pressure was 28, and have never had excessive wear in the center of the tread. As has already been said, this would be a problem if running bias ply tires, but who does that these days?
Well my Goodyear triple treads are doing exactly that. 4/32 in the middle (thankfully that is where they are measuring) to 8/32 on the sides. They were equal when I put them on.
Not the first time I've had this happen.
AGAIN, I'm NOT talking about BIAS ply tires!
Originally Posted By: Bill in Utah
Let's say the tire is rated on the vehicle for 30 PSI. Sidewall rating is 44PSI.
Run the tire @ 40 PSI and you WILL wear out the center part of the tread by OVER inflation.
I've done exactly this and have never had a tire wear more in the center of the tread. I've also run other tires at their max sidewall load of 35psi, when the recommended pressure was 28, and have never had excessive wear in the center of the tread. As has already been said, this would be a problem if running bias ply tires, but who does that these days?
Well my Goodyear triple treads are doing exactly that. 4/32 in the middle (thankfully that is where they are measuring) to 8/32 on the sides. They were equal when I put them on.
Not the first time I've had this happen.
AGAIN, I'm NOT talking about BIAS ply tires!
Yeah, the centers on my Gerneral Exclaim UHPs are worn as well. I ran 35-40psi before I discovered I should be running more like 30psi.
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Originally Posted By: Bill in Utah
Well my Goodyear triple treads are doing exactly that. 4/32 in the middle (thankfully that is where they are measuring) to 8/32 on the sides. They were equal when I put them on.
Not the first time I've had this happen.
AGAIN, I'm NOT talking about BIAS ply tires!
+1
Same thing on my 530i - centers wear out faster than sides if I run more PSI than what the vehicle placard recommends.
Well my Goodyear triple treads are doing exactly that. 4/32 in the middle (thankfully that is where they are measuring) to 8/32 on the sides. They were equal when I put them on.
Not the first time I've had this happen.
AGAIN, I'm NOT talking about BIAS ply tires!
+1
Same thing on my 530i - centers wear out faster than sides if I run more PSI than what the vehicle placard recommends.
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