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2005 CTS-"V"
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I have just replaced my factory F1 run-flats with Dunlop SportMaxx non-run-flat tires. I have a question about the correct tire pressure I should use on the new tires. The door jamb calls for 30lbs on the factory run-flats. This seems too low, especially considering the extreme wear noticed on my original front tires on the edges. The center of the tires were fine, while the edges wore down to thread in less than 20k miles. Amazingly the rear tires still have quite a bit of life considering how soft the F1's are by nature. I just had my alignment done by one of the best independent alignment men in the area and he suggested closer to 40lbs, which seems a bit high, while my new Dunlops show a max of 50lbs per tire. Any ideas on a good in between pressure that will maximize tire life while not killing ride performance??
 

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i got the same tire cold is 32-33 they warm up to 35-37 depending on how hard im driving. at the track they see about 39-41 on long times out. also i have nitro filled tires.
 

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Start at 30, work your way up or down based on your preference for handling and ride.
The fronts will always wear on the edges, that is why you rotate them as you know.
If the tire pressures were causing wear the rears would show the same pattern.
As the tires warm up the pressures will rise.
 

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The Dunlops need higher pressures to firm up the sidewall than the F1s did. What you want is about 39-41 hot. In the winter, it would be about 27-30 cold. In the summer about 33 cold. Unless you're running long distances on incredibly hot days, that should keep you out of the ding-ding-dinger.
 

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i got the same tire cold is 32-33 they warm up to 35-37 depending on how hard im driving. at the track they see about 39-41 on long times out. also i have nitro filled tires.
I was under the impression the nitro filled tires didn't increase psi with heat....am I wrong?

But ya, I run my front's at 32-33 and my rears and 30-31...seems to wear pretty evenely.
 

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They are not supposed to but they do on my car. They do rise less psi then when i was using just air. so i think that its slightly better, but not much. I get it for free anyways so i figure why not.
 

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yo bigjim, 30 in winter and 33 in summer???? do u have that backwards or am i missing something.?
When it gets colder, your tires lose pressure. I've seen a cold ambient temp reduce the tire pressures about 3-4psi. And while a cold road will reduce the heat in a tire, the tire will still heat up to a temp that's close to a hot road in summer.

Basically, a tire that is 33 cold when it's 70 degrees out will be 29 when it's 30 degrees out without touching anything. I just find the temp range from backing out of the driveway to a long highway drive on a cold day is greater. So I generally leave a 29 psi tire as it is in the winter(or a generally cold day since I store my V in the winter).
 
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