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I know that the door jam tells us what tire pressure should be in the OEM tire that came with my car. But a mere 700 miles into ownership I went with a different set of tires. The factory GoodYear F1 (245/45/20) said Max pressure 51 and I ran them at the door jam recommendation of 32 psi. My new Pirelli PZ4 Sports (same size) feel a hell of a lot better on the car (isolation & stickiness) but the steering is a bit harder than the F1's. I can adjust by going to "comfort mode" on the steering but I wonder if I should adjust the pressure up a bit? Anyone running a little higher pressure on their tires?

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No expert here, but I did stay at a Holiday Inn last week. I would think that following the door recommendation is there more for the TPMS to report on. If it's higher, I don't believe it would hurt anything.
 

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No expert here, but I did stay at a Holiday Inn last week. I would think that following the door recommendation is there more for the TPMS to report on. If it's higher, I don't believe it would hurt anything.
I think the door recommendation displays the optimum pressure based on the car & OEM tire combo. Meaning, weight of the car and other factors. That's why I wonder if my "revised" tire and car combo would demand a different pressure. I'm probably overthinking it. I guess there wouldn't be too big a difference between two summer tires with the same max pressure. Just curious, and the heavier steering got me thinking. The Pirelli is an XL tire and the stock F1 is SL though...

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Same tire size and load rating, use door decal pressure. If the load rating is higher or a larger tire with a higher load rating is installed, lowered pressure is called for.
Example, my 11 Challenger calls for 32 for the 245/45x20 (load rated 99) tires. I changed the rear to 275/40x20 (load rated 106) and reduced the pressure to 28 psi. this gives full contact patch and stable handling.
 

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Tire manufacturers seem to give a wide psi recommendation with max. pressure. I have Conti. Extreme Sports on mine, 285/35, and still run them with 32 to 35 psi, depending on outside temp. and particular use that day.
 

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I know that the door jam tells us what tire pressure should be in the OEM tire that came with my car. But a mere 700 miles into ownership I went with a different set of tires. The factory GoodYear F1 (245/45/20) said Max pressure 51 and I ran them at the door jam recommendation of 32 psi. My new Pirelli PZ4 Sports (same size) feel a hell of a lot better on the car (isolation & stickiness) but the steering is a bit harder than the F1's. I can adjust by going to "comfort mode" on the steering but I wonder if I should adjust the pressure up a bit? Anyone running a little higher pressure on their tires?

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I always run more pressure in front then back unless its an AWD vehicle.

I think on my Hankook S3 im running 36 f 30 rear. I dont think the Hankooks steer as sharp with lower air pressure and I have them on two different cars.
 

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Same tire size and load rating, use door decal pressure. If the load rating is higher or a larger tire with a higher load rating is installed, lowered pressure is called for.
Example, my 11 Challenger calls for 32 for the 245/45x20 (load rated 99) tires. I changed the rear to 275/40x20 (load rated 106) and reduced the pressure to 28 psi. this gives full contact patch and stable handling.
The car manufacturer recommends 32 psi for my 275/40x20 (load rated 106) on my SRT 392.
So is this because the extra 200 lbs(roughly 50 lbs per tire.) of the SRT makes the difference for getting the full contact patch?
 

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The car manufacturer recommends 32 psi for my 275/40x20 (load rated 106) on my SRT 392.
So is this because the extra 200 lbs(roughly 50 lbs per tire.) of the SRT makes the difference for getting the full contact patch?
Not likely, mine is also an SRT. Even though it had the 255/45x20 tires on the rear, the decal shows 32 psi. This gave poor traction and wore out the tires in the center prematurely.
 

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Not likely, mine is also an SRT. Even though it had the 255/45x20 tires on the rear, the decal shows 32 psi. This gave poor traction and wore out the tires in the center prematurely.
Yes, I always felt that over inflating can wear out the tire center sooner while under inflating can wear out the edges more. Don't really know if that's always true.
 

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"They" say...put a chalk line across the tread and drive a bit. See if it wears off uniformly. Inflate/deflate as needed. A Guy
 

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Door jam numbers are based on total vehicle weight divided by 4. Hence all 4 tires listed as same psi. My rear 275's are Y106XL 2094 lbs, front are 245's Y103XL 1929 lbs at max psi. Obviously the tires are only loaded to a little over 1/2 of that.

It doesn't take into account the front of the car is heavier than the rear.

I think the following is more realistic.
28-30 rear
34-36 front

I drove in a parking that was white with dry salt. It is easy to see I need a couple more psi in the front and a couple less in the rear as the edge if the 275's in the rear are not touching the pavement like the front are at 32 psi.

If you put another Hemi in the trunk, equal psi on all 4 would be more accurate.
 
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