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Old 01-05-2012, 08:30 PM   #11 (permalink)
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On my Toyota Matrix I put my tire to max side wall and have gotten better coasting and better wear. I would start with max side wall then try 2-4 psi over.

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Old 01-09-2012, 04:04 AM   #12 (permalink)
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So you shouldn't really go as high as you dare. Cause I dare go maybe... 65 PSI.
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Old 01-09-2012, 07:15 AM   #13 (permalink)
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Quote:
Originally Posted by Photonfanatic View Post
So you shouldn't really go as high as you dare. Cause I dare go maybe... 65 PSI.
There's no real need to go very high.
On normal passenger car tires, you'll already get most of the benefits around 45-50 psi .
45-50 psi is usually already beyond the specification of the car manufacturer, and into the tire manufacturer's sidewall max. allowable pressure range.

Increasing the pressure further , the effect on your MPG will become less and less noticeable - the law of diminishing returns.

By increasing the pressure further, you can also run into other problems, like a very harsh ride, wheel bounce, the suspension not coping with the bouncing wheels, uneven wear, ... so you need to watch the tires closely when going to or beyond the advertised sidewall maximum.


I run the tires at sidewall max. pressure, winter and summer.
Increasing the pressure beyond that limit, made the rear of the car bouncy, so I backed off a bit.
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Old 01-09-2012, 09:23 AM   #14 (permalink)
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Quote:
Originally Posted by euromodder View Post
There's no real need to go very high.
On normal passenger car tires, you'll already get most of the benefits around 45-50 psi .
45-50 psi is usually already beyond the specification of the car manufacturer, and into the tire manufacturer's sidewall max. allowable pressure range.

Increasing the pressure further , the effect on your MPG will become less and less noticeable - the law of diminishing returns.

By increasing the pressure further, you can also run into other problems, like a very harsh ride, wheel bounce, the suspension not coping with the bouncing wheels, uneven wear, ... so you need to watch the tires closely when going to or beyond the advertised sidewall maximum.
Something that is not part of this discussion yet: the ambient temp at which you pump/check tires and the day-to-day temp variation. I pumped my tires to 60psi in the warmest daytime temps available because I'm going to lose a lot of that pressure in the colder morning and evening hours. If you pump the tires in the middle afternoon to say 50psi, early the next morning you will not be running at that psi when you head off to work.

I'm at 60psi and the ride is harder, but the wear and handling are fine. We're not driving race cars ...

One thing to be aware of: if you have tire-pressure sensors on your car they might give you a warning if you go more than 5 or 6 psi over pressure.

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Old 01-09-2012, 02:38 PM   #15 (permalink)
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A couple of things:

First, from what I've read, your tire pressure should vary ~ 1 psi for every 10 degrees of temperature. In reference to one of California98Civic's earlier posts, I neutral coast about 5 mph faster down a particular hill with just a 30-40 degree temperature shift (so roughly 3-4 psi).

Second, I have a TPMS installed, and I have not noticed any issues with going over pressure. My stock tires had a max sidewall of 42 psi, and my current tires have a max sidewall of 51 psi. I'm running at max (morning inflation), and I have not had the system kick anything back, even at > 10 psi over what the sensors are calibrated for. One caveat with that, though, is that each manufacturer tends to use their own tire pressure system, so this might not be universal.
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Old 01-09-2012, 06:48 PM   #16 (permalink)
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Originally Posted by Ladogaboy View Post
One caveat with that, though, is that each manufacturer tends to use their own tire pressure system, so this might not be universal.
My wife's 2010 subaru tire pressure monitor set off a dash warning light once, and I checked the pressure for her: highest PSI was 50 (IIRC) and the tires were rated for 44. They had been inflated to 45/46 by me in cooler morning temps. Just my experience.
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Old 01-09-2012, 06:59 PM   #17 (permalink)
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Originally Posted by California98Civic View Post
My wife's 2010 subaru tire pressure monitor set off a dash warning light once, and I checked the pressure for her: highest PSI was 50 (IIRC) and the tires were rated for 44. They had been inflated to 45/46 by me in cooler morning temps. Just my experience.
Yeah, that's why I mentioned that mine were fine. Most manufacturers use a proprietary sensor setup... might be a useful tool to put up at some point: A thread with feedback based on manufacturer. So, from my end, Mitsubishi is fine @ ~ 10 psi over.
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Old 01-10-2012, 02:27 AM   #18 (permalink)
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Or you could fill with nitrogen and never have to worry about the PSI changing due to outside temperatures. Just tell them you want it 5 PSI over when they do it. Kind of expensive though, for trucks at my local tire shop its like $100 per wheel. Be worth it I guess if you never had a flat and didn't change the tires until they were completely wore out. And you had them filled with the nitrogen when they were brand new.

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