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I followed Toyota's recommendations when the car was new, and my original Integrity tires wore out in abotu 20K miles. THe center had plenty of tread left, but the edges were worn bare.

I replaced the tires with ComforTreds and use pressures of about 40F/38R. My tires have gone 50K miles and have tread left, and have worn more evenly. They do not ride hard at this pressure because of the cushioning layer in this model tire. I am sure they would be softer still at lower pressures, but they feel as smooth as the Integrities did at stock pressures.

I didn't do it for gas mileage, but it undoubtedly helped in that area also. But it was mainly to get decent tire life and wear. I do mixed freeway/suburban stop'n'go, sometimes in the wet but never in the snow.
 

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wstander said:
Kingetula said:
So to save money at the pump we inflate our tires and spend that money we saved at the pump buying new tires sooner? (LOL)

Aaaayyuuuuppp!

Better to send my money to Yokohama in Japan than to OPEC:)
Except that with the Integrities over inflating improves the life of the tire, not decreases it. At 50/48 mine are about at the end of their life and are still most worn on the outside edges.

PA P
 

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PA Prius said:
wstander said:
Kingetula said:
So to save money at the pump we inflate our tires and spend that money we saved at the pump buying new tires sooner? (LOL)

Aaaayyuuuuppp!

Better to send my money to Yokohama in Japan than to OPEC:)
Except that with the Integrities over inflating improves the life of the tire, not decreases it. At 50/48 mine are about at the end of their life and are still most worn on the outside edges.

PA P
PA,

The GY integrities, max cold pressure is 45 psi ? Isn't it? 50 psi in your tire is "Over inflated" I think. I will go with the general concensus of _a little under_ as prescribed in the tire wall.
F42 psi/ R40 psi is very much in line, and I like the overall driving feel.
 

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Right, they are over inflated according to the sidewall max. I am not concerned since we drive very conservatively and even more so on wet roads, we do not drive about 1000' elevation, and bursting strength is four to five times that of the sidewall max.

PA P
 

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I'm wondering if there is anybody else from Arizona (Scottsdale) where our summer temps exceed 100 consistently. Is there any risk in inflating tires to the 42/40 or even higher psi during our intensly hot summers? I don't want to be blown to the moon!!!
 

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I live over the hill in Ramona, CA where we regularly scratch 100-110 in late summer, and 90-99 currently. I have run 42/40 on my 2005 for years with no problems.

I used to race at Firebird, when track temps hit 150 and the ambient was 110 at 10PM. We all ran 42 front and 44 rear on street tires without failure...some even went as high as 50 on the outside tires....

Other than a little firmer, and noisier ride, no issues:)
 

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C.Rickey Hirose said:
The GY integrities, max cold pressure is 45 psi ? Isn't it? 50 psi in your tire is "Over inflated" I think. I will go with the general concensus of _a little under_ as prescribed in the tire wall.
F42 psi/ R40 psi is very much in line, and I like the overall driving feel.
This is not "a little under" but "a lot over". The sidewall figure is the MAX and is independent of what car the tire is installed on. Yes, you are under the sidewall max, but this is a MAX, not a "prescribed" value.

I agree with the "higher then owner's manual recommended" pressure, and I would NEVER inflate them over the MAX on the sidewall.
 

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90K with Michelin Energy Saver A/S

I found no problem inflating tires to 40 rear, 42 front and just bought new Michelin Energy Saver A/S after getting 90,000+ miles out of previous identical tires.

Local tire dealer grudgingly gave me those pressures, saying, "You'll wear them out quicker." So I guess I could have gotten over 100,000 miles.

No unusual wear pattern; car tracked straight as an arrow on x-way; no problem with handling.

I once got 60+ mpg (display said 63, always too high) from Kansas City to Cincinnati (close to 600 miles) on a summer weekday, going 55mph except when traffic dictated going faster. Filled up in KC and drove straight through except for usual stops.
 

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If you are using helium instead of regular air, there is no problem with slightly over-inflated tires. But if you are using regular air, then don't over-inflate in hot weather.

Safety guidelines do not recommend over-inflating in hot weather no matter what you use to inflate your tires with, but I have never had a problem in hot weather while using helium in my tires. I live in Arizona.

The additional increase in mileage with over-inflated tires may not be significant depending on your driving habits.

Jack-rabbit starts and excessive high speeds reduce your mileage considerably.

John C.

Hi All,

Got a questions for you guys out there...

I own a Year08 Prius. I do try to make sure the tires are inflated according to the values recommended by Toyota. This means that I'm going by the values indicated on the sticker found on the door (is it the driver side or front passenger side? I can't remember which).

Having read other posts earlier, it seems to me that many are claiming 42front/40back would boost MPG even more! So questions are:

1) Is it save to inflate higher than the manufacturer's recommended values? I'm also worried the tire would burst on me all of a sudden...
2) Why 42/40? Did somebody out there do some kind of comprehensive tire pressure test and conclude that 42/40 is the sweet spot?

Thanks all for your help! Look forward to hear from you guys!

Joe
 

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I inflate the tires slightly more than what is stated in the manual. Tires always loose pressure over time. I don't think a reasonable increase in pressure is harmful, since the stiffer the tire, the less it will flex, the less it will heat up, and the less it will gain pressure. But what do I know, I've only been checking tired inflation for 55 years.
 
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