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30 vs 35 PSI - Tire Pressure

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Fritzo

Lifer
Jan 3, 2001
41,501
1,661
126
If it's just 5 PSI, it'll hold OK, and you'll get better gas milage. However your savings may be eaten up by early center wear on your tires.
 

BUTCH1

Lifer
Jul 15, 2000
20,031
1,532
126
Yes 30 PSI is too low. It's for grandpa's and grandma's. Jack it up to 42 PSI both front and back. Your tires should be rated at upto 44 PSI if I'm not mistaken. So check the max allowed PSI on the tires first. Most are 44 PSI.

Yes it will help fuel economy as the rolling resistance on the tires have reduced tremendously.



He's got plenty rooms. Jack it up 10 PSI or so.


cheez
So your saying........INFLATE TO SIDEWALL!!!!!!!!!!!!!!!!!!!!!
 

Ferzerp

Diamond Member
Oct 12, 1999
6,435
106
106
Depends on the car, depends on the tire, depends on how you're driving......

In other words, trust your car manufacturer instead of random internet folks :p

Also, I was reading the manual for my car on order tonight, it says 26 PSI for track duty with the OEM tires.
 
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tortillasoup

Golden Member
Jan 12, 2011
1,974
3
81
If it's just 5 PSI, it'll hold OK, and you'll get better gas milage. However your savings may be eaten up by early center wear on your tires.
Unlikely to happen but if it does happen, op can always reduce the pressure next time. My friend's car had the pressure at like 60psi, way way too high on the rear tires of his car. He regularly inflated his tires at the gas station and I guess pressure gauge wasn't too accurate so when it came time to replace his tires, he found that the rear did wear unevenly but it was only like a difference of 2/32" which is a lot less than you'd expect with such a huge pressure difference between what the manufacturer recommends (his car 30psi) and what they were.

For me personally I keep a lot more pressure in the front tires than the rear as I drive in hilly areas and my tires wear down the sides a lot if I don't keep them up. If you find the car rides unsatisfactorily you can always reduce the pressure but I think you'll find you like the extra pressure compared to what the factory recommends.
 

DaTT

Garage Moderator
Moderator
Feb 13, 2003
13,288
117
106
Unlikely to happen but if it does happen, op can always reduce the pressure next time. My friend's car had the pressure at like 60psi, way way too high on the rear tires of his car. He regularly inflated his tires at the gas station and I guess pressure gauge wasn't too accurate so when it came time to replace his tires, he found that the rear did wear unevenly but it was only like a difference of 2/32" which is a lot less than you'd expect with such a huge pressure difference between what the manufacturer recommends (his car 30psi) and what they were.

For me personally I keep a lot more pressure in the front tires than the rear as I drive in hilly areas and my tires wear down the sides a lot if I don't keep them up. If you find the car rides unsatisfactorily you can always reduce the pressure but I think you'll find you like the extra pressure compared to what the factory recommends.
I run 34psi on my Eagle F1 Supercar tires and I just noticed last week that there is significant center wear on my treads. New tires for me next summer.
 

Ferzerp

Diamond Member
Oct 12, 1999
6,435
106
106
I run 34psi on my Eagle F1 Supercar tires and I just noticed last week that there is significant center wear on my treads. New tires for me next summer.
Ugh. Those are awful tires. Replace them asap anyway!!!
 

DaTT

Garage Moderator
Moderator
Feb 13, 2003
13,288
117
106
Ugh. Those are awful tires. Replace them asap anyway!!!
I am next summer. Got the SVT rims and tires (brand new) for $800. Tires were better than the Pirelli Pzero Nero's that came stock.

What pressure were you running on your GT500?
 

Gillbot

Lifer
Jan 11, 2001
28,830
17
81
Use the Chalk Method.
Let the chalk tell you

You can also “calculate” your tire pressure with the chalk method. This involves coloring a section of your tire with chalk to see how much tread is making contact with the ground. Start by finding a flat road surface. Concrete is actually the best choice, but you can also do this on asphalt. Make a mark with soft chalk that goes all the way across your tread. Then, gradually drive your truck forward about 50 feet and then backwards 50 feet.

Analyze the chalk on the tire. If the chalk is only worn off on the center of the tire, reduce the tire pressure slightly and go through the process again. With the adjustment, you should see the chalk wear off more broadly. Keep making tiny adjustments in the tire pressure until the chalk wears off evenly and all the way across the tread.

You will have to complete this process for each of your four tires. Once you’ve found the right street pressure, add 10% to all four tires. Then, measure the tires and add pressure to balance them. As explained above, you need to measure from the wheel to the ground. Start by balancing the profiles of the front tires with each other. Then, balance the front tires again with the rear tires. Always adjust the tires with the smaller profiles by adding air.

The advantages and disadvantages of this method are the same as those involved in the second method above. If you go through the process correctly, you end up with the ideal tire pressure. But, this method is tedious and there’s a reasonable chance that you will make a mistake.
 

tortillasoup

Golden Member
Jan 12, 2011
1,974
3
81
285/40/18 in the back and 255/45/18 in the front
Yeah those are really huge tires so if you've got a light weight car, I could see that happening. On more narrow tires, like say 215mm I've never had the tires wear unevenly from more pressure. Then again a 215mm wide tire on a 3500lb vehicle is likely similar to a 185mm wide tire on a 2400lb car, again another car I've never see wear unevenly. Larger tires unless specified as Low Load (vs. standard/extra load) have more load carrying capacity so with more pressure might have a higher tendency to wear in the center with more air...

But yeah as everybody has said, those are shitty tires.
 

DaTT

Garage Moderator
Moderator
Feb 13, 2003
13,288
117
106
Yeah those are really huge tires so if you've got a light weight car, I could see that happening. On more narrow tires, like say 215mm I've never had the tires wear unevenly from more pressure. Then again a 215mm wide tire on a 3500lb vehicle is likely similar to a 185mm wide tire on a 2400lb car, again another car I've never see wear unevenly. Larger tires unless specified as Low Load (vs. standard/extra load) have more load carrying capacity so with more pressure might have a higher tendency to wear in the center with more air...

But yeah as everybody has said, those are shitty tires.
Couldn't beat the price
 

kitatech

Senior member
Jan 7, 2013
484
3
81
I had 35psi in OEM tires on my Camry (spec'd for 29psi), and recently tried 37 for a long highway trip and found that 37psi was too much...lost A LOT of wet surface traction....
 

WoodButcher

Platinum Member
Mar 10, 2001
2,158
0
76
Remember Door Jam PSI is for the stock tires. For Ex: Pressure inside the tires affects load rating and its speed rating. So it can be different vs stock.

You should be able to run 35psi without issue imo.
The highlighted bit is very simple. If the OP is running the same tire that the engineers designed the car with this will be the pressure to expect the best all round performance of the car. The tire may be rated higher as it is designed to be used on more than one vehicle, check the tire manufacturers listings to see if it is meant to be used on your car.

Here comes the fun part, where I get flamed or not as this is my opinion.
I always start at the highest pressure recommended on the sidewall then reduce the pressure by small amounts after test driving until I get to the auto manufacturer recommendations + or - a few pounds and then choose what pressure I'll be running at on a daily basis that fits my driving style, load and road conditions. There is no one size fits all answer, you need to determine what is best for you, within the limitations of the tire and vehicle.
 
Sep 7, 2009
12,960
3
0
Well I'm going to disagree with the entire 'inflate to sidewall' thing which we've hashed out countless times over the years.


Start out at door pressure. In the op's case, 30psi, I would probably run 35-37psi. Being that it's a buick they are going for ride-quality first, handling second.
 

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