Ok gas prices in Tampa are creeping up to 3.00 a gallon, so to save a little fuel I am going to increase my p.s.i to 40 the car calls for 30. Other then the discomfort of a hard tire are there any ill effects that I should be aware of? Thanks.
Running P.s.i Higher to save fuel.
- Thread starter kevco
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If you prematurely wear out the center of your tread any fuel savings will be needed to replace tires. Taking temps across the tread after they are at operating temp. Warmer temps will tell you areas where they will wear out first. You can find your PSI sweet spot this way. The car manufacturers spec is about a good as it gets in most cases but different tires may like a little more or less psi.
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Originally Posted By: willix
If you prematurely wear out the center of your tread any fuel savings will be needed to replace tires.
I've been running ~8-10psi higher than recommended pressures in my cars and have yet to see a tire wear more in the centre... Over 80,000 miles on the tracker tires and they are wearing normally. Recommended is 28psi, which I can only guess was chosen to make the ride smoother. With 35 or 38psi it actually turns when you turn the steering wheel...
If you prematurely wear out the center of your tread any fuel savings will be needed to replace tires.
I've been running ~8-10psi higher than recommended pressures in my cars and have yet to see a tire wear more in the centre... Over 80,000 miles on the tracker tires and they are wearing normally. Recommended is 28psi, which I can only guess was chosen to make the ride smoother. With 35 or 38psi it actually turns when you turn the steering wheel...
When the tire heats it rises in PSI however having higher PSI causes the tire to run cooler. To dial in a PSI improvment over the recommended requires a pyrometer or infrared temp gun to take tread temps. across the contact patch. There is a max PSI on the sidewall and you don't want to exceed that spec. Most passenger tires are around 40-45PSI. running max psi doesn't mean the tread will wear even. Hi psi = centerwear- low psi = shoulder wear
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Originally Posted By: kevco
The car is a 2005 Corolla with Yokohama size 195/65 r15 tire model as530
I have the same car but factory Bridgestone. I run 3 PSI above the recommended about 33 PSI (cold tire). When the front tires heat up they get up to about 36 or 37 on a hot day.
My tire wear looks pretty even. You need to account for the increase in PSI when the tires get hot. Don't go too crazy over inflating your tires. 10 PSI over recommended is too much IMO. There should be a max PSI rating for your tires. Just make sure your hot tire PSI doesn't go above that.
The car is a 2005 Corolla with Yokohama size 195/65 r15 tire model as530
I have the same car but factory Bridgestone. I run 3 PSI above the recommended about 33 PSI (cold tire). When the front tires heat up they get up to about 36 or 37 on a hot day.
My tire wear looks pretty even. You need to account for the increase in PSI when the tires get hot. Don't go too crazy over inflating your tires. 10 PSI over recommended is too much IMO. There should be a max PSI rating for your tires. Just make sure your hot tire PSI doesn't go above that.
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Originally Posted By: IndyIan
Originally Posted By: willix
If you prematurely wear out the center of your tread any fuel savings will be needed to replace tires.
I've been running ~8-10psi higher than recommended pressures in my cars and have yet to see a tire wear more in the centre... Over 80,000 miles on the tracker tires and they are wearing normally. Recommended is 28psi, which I can only guess was chosen to make the ride smoother. With 35 or 38psi it actually turns when you turn the steering wheel...
+1, radials are reasonably tolerant of pressure variations as far as evenness of wear goes.
See
http://www.barrystiretech.com/sae800087synopsis.html
Bias and bias-belted tires are not so forgiving.
Capriracer, Thanks for your website.
Originally Posted By: willix
If you prematurely wear out the center of your tread any fuel savings will be needed to replace tires.
I've been running ~8-10psi higher than recommended pressures in my cars and have yet to see a tire wear more in the centre... Over 80,000 miles on the tracker tires and they are wearing normally. Recommended is 28psi, which I can only guess was chosen to make the ride smoother. With 35 or 38psi it actually turns when you turn the steering wheel...
+1, radials are reasonably tolerant of pressure variations as far as evenness of wear goes.
See
http://www.barrystiretech.com/sae800087synopsis.html
Bias and bias-belted tires are not so forgiving.
Capriracer, Thanks for your website.
Also it may not be a visual indication until the tread wears away after so many miles then you will see uneven wear. Most neglect to maintain psi and experience excess shoulder wear.
I've had good results running my Mazda's tires at 40 psi.
I ran the first set of tires at factory psi (32) and even though I drive mostly interstate/country hwy I was getting shoulder wear from the corners.
For my second set I have ran them at 40 psi entirely and after 40,000 miles they are wearing pretty even.
As far as mpg goes, I noticed a very small increase, a lot of times the weather or traffic is a much bigger factor. Do not expect a lot. There are a lot of other techniques to save gas.
I ran the first set of tires at factory psi (32) and even though I drive mostly interstate/country hwy I was getting shoulder wear from the corners.
For my second set I have ran them at 40 psi entirely and after 40,000 miles they are wearing pretty even.
As far as mpg goes, I noticed a very small increase, a lot of times the weather or traffic is a much bigger factor. Do not expect a lot. There are a lot of other techniques to save gas.
I have high performance all seasons on mine that allow up to a 51 psi max pressure. Tried that once and I could feel every bump on the road. No real improvements in gas mileage, and I keep a meticulous record. Only good thing is that I haven't had to add air since November. Currently the pressure is at about 40 psi. Ride is good and still no mileage difference. I find driving at or below the speed limit with less stop and go traffic helps a lot more with mpg. I recently took a trip accumulating 240 miles total of highway driving. about a third was 55-60 mph and I got the best mileage on my car ever, 27 mpg. Normally get lower 20s.
Originally Posted By: asiancivicmaniac
I have high performance all seasons on mine that allow up to a 51 psi max pressure. Tried that once and I could feel every bump on the road. No real improvements in gas mileage, and I keep a meticulous record.
Yup. The law of diminishing returns. You basically get poor mpg if you allow your tire pressure to drop below what the mfg recommends, but if you go much above it, it doesn't make that much of an improvement in mpg, at least in my experience. Plus, you're just causing yourself an unnecessarily harsh ride and probably shortening the life of various suspension components which now have to dampen whatever the stiffer tires won't.
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I find driving at or below the speed limit with less stop and go traffic helps a lot more with mpg.
+1
I can't get myself to do it, but I agree.
I have high performance all seasons on mine that allow up to a 51 psi max pressure. Tried that once and I could feel every bump on the road. No real improvements in gas mileage, and I keep a meticulous record.
Yup. The law of diminishing returns. You basically get poor mpg if you allow your tire pressure to drop below what the mfg recommends, but if you go much above it, it doesn't make that much of an improvement in mpg, at least in my experience. Plus, you're just causing yourself an unnecessarily harsh ride and probably shortening the life of various suspension components which now have to dampen whatever the stiffer tires won't.
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I find driving at or below the speed limit with less stop and go traffic helps a lot more with mpg.
+1
I can't get myself to do it, but I agree.
I've run my Pirelli P4's at 40 PSI since new (sidewall max is 44 PSI, door sticker says 30 PSI for ride comfort). They're wearing evenly. The car actually turns with the tires at 40 PSI, and the ride is just fine. YMMV...
Airing up the tires is a good first step. Adjusting the nut behind the wheel is a necessary second step for better fuel mileage.
If you want to really save, get some device that gives you instant feedback on your fuel-conserving efforts.
Airing up the tires is a good first step. Adjusting the nut behind the wheel is a necessary second step for better fuel mileage.
If you want to really save, get some device that gives you instant feedback on your fuel-conserving efforts.
Like many others on here, I usually run my tires 5 to 10 lbs above the manufacturers recommendations. No, they never wear out early in the center. Crisp handling is assured, gas mileage improvements are small but measurable. When towing, tail-wag is great reduced or eliminated by running the tires near the top of their sidewall rating.
Yeah, the nut behind the wheel is the biggest controller of gas mileage. Looking further ahead and letting off the accelerator much earlier as you approach a red light will:
Reduce your fuel consumption
Increase your brake life
Make you a safer driver, especially in snow or when towing
Not change your average speed at all..... remember the light is red!! Why do all the idiots.... most everybody.... continue to power all the way to a red light, brake hard to a stop.... just in time to see it turn green??
Of course, vehicle selection is most important.... assuming you are ready to trade anyway.
Since I am heavily involved in team towing.... and I always tow the heaviest boat on our team, we often record mileage as we fill all the vehicles at one time.
Towing 5,000 lbs, our Suburban will average 9 mpg, our 4wd F150 can get 11, a 2wd chevy pickup gets 12, and a minivan gets 18.
Yeah, the nut behind the wheel is the biggest controller of gas mileage. Looking further ahead and letting off the accelerator much earlier as you approach a red light will:
Reduce your fuel consumption
Increase your brake life
Make you a safer driver, especially in snow or when towing
Not change your average speed at all..... remember the light is red!! Why do all the idiots.... most everybody.... continue to power all the way to a red light, brake hard to a stop.... just in time to see it turn green??
Of course, vehicle selection is most important.... assuming you are ready to trade anyway.
Since I am heavily involved in team towing.... and I always tow the heaviest boat on our team, we often record mileage as we fill all the vehicles at one time.
Towing 5,000 lbs, our Suburban will average 9 mpg, our 4wd F150 can get 11, a 2wd chevy pickup gets 12, and a minivan gets 18.
Read an interesting theory that tires at recommended PSI deflect over bumps and respond quickly enough to push against those bumps after covering them, turning that force back into motion. If it goes into your struts it turns into heat and loses energy.
I inflate to a point between door jam and sidewall for the improved steering feel etc but mileage is negligible. Just pulled some great MPG on clunky snow tires of all things thanks to temperate spring weather... windows cracked, less warmup.
I inflate to a point between door jam and sidewall for the improved steering feel etc but mileage is negligible. Just pulled some great MPG on clunky snow tires of all things thanks to temperate spring weather... windows cracked, less warmup.
Coast down tests, Metro and Camry
The metro with skinny high profile tires coasted quite a bit farther with 40 psi than 30. The camry with lower profile tires didn't. You could figure out how much less drag there is but I don't have time to revive my highschool physics skills...
The metro with skinny high profile tires coasted quite a bit farther with 40 psi than 30. The camry with lower profile tires didn't. You could figure out how much less drag there is but I don't have time to revive my highschool physics skills...
I would have the concern of the tire performance and behavior being compromised in bad conditions or panic situations.
Usually I found 2-3 PSI above mfg recommendation to be ideal, some tires that are famous for thin sidewall need another 2-3 PSI (i.e. Sumitomo HTR 200)
This is my experience with 40k miles on my tires, most of it at a few PSI below sidewall pressure: The handling gets a bit more precise. The car rolls longer with my foot off the gas. The rims don't hit the potholes I can't see at night.
Once after a cold snap my tires dropped to 33 PSI, and the car would gladly roll onto the sidewall during a turn, something it didn't do at 40 PSI. (205/70-15 Pirelli P4's on a Buick LeSabre)
That's my experience. For what it's worth.
Once after a cold snap my tires dropped to 33 PSI, and the car would gladly roll onto the sidewall during a turn, something it didn't do at 40 PSI. (205/70-15 Pirelli P4's on a Buick LeSabre)
That's my experience. For what it's worth.
I like the metrompg site. I gotta say running too high a pressure although frugal, may be deadly.
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