AWD tire psi

[carvinbassplyr]

First off, I have searched on here and elsewhere and did find a few threads related to this via dsmtalk, but I just wanted to make sure I was understanding everything correctly. I know since these cars were being manufactured many companies have gone with higher recommended psi's to help with the gas mileage of their vehicles. I would like to raise the pressure in my tires for better handling and mpg and my question is do I need to follow the staggered stock psi ratings (3 psi difference front to back) as I raise it? I believe that they staggered it from the factory because there's so much weight on the front tires from the motor and trans that it caused the front tires to squat more than the rears. Since you need all the tires to have the same, or extremely close, rolling diameter they had to compensate for the greater load on the front tires. I just don't want to put any more stress on the diffs than necessary and I wasn't sure if there would be any adverse effects on the AWD components by raising/matching the psi all the way around? I am running 225/50/16 tires with a 51 PSI max rating. Thanks in advance!

 

[carvinbassplyr]

Another thought I had....is the difference between the front and rear tires based in a set numerical psi value or the percentage of 1 tire vs the other? Example 32 front/29 rear is 3 psi apart, and 29/32~91%. So do you just keep the tires 3 psi apart as you increase the pressure or do you multiply your front pressure by 91% (.91) to determine your rear pressure?

 

[buddy3824]

I'm not exactly sure what you are trying to achieve here. gas mileage is more affected by your foot vs psi. yes high helps, but you are also wearing the center of the tire a lot faster and would also create more heat as you are lessening the straight away contact patch. I run 27 psi front and back in my car. I get about 21mpg with a 20g and I'm on it all the time. as far as handling. psi depends on when the sidewall of the tire starts to roll. for my coopers, 28psi is pretty much the sweet spot. some tires need upwards of 40psi to handle well.
yes porsche and audi and some bmw's have stock psi in the 40 psi range. it is what it is. but most newer cars are still in the 30-35 range..

 

[carvinbassplyr]

I'm not exactly sure what you are trying to achieve here. gas mileage is more affected by your foot vs psi. yes high helps, but you are also wearing the center of the tire a lot faster and would also create more heat as you are lessening the straight away contact patch. I run 27 psi front and back in my car. I get about 21mpg with a 20g and I'm on it all the time. as far as handling. psi depends on when the sidewall of the tire starts to roll. for my coopers, 28psi is pretty much the sweet spot. some tires need upwards of 40psi to handle well.
yes porsche and audi and some bmw's have stock psi in the 40 psi range. it is what it is. but most newer cars are still in the 30-35 range..

I hear what your saying, but lessening the rolling resistance will add more mpg's especially at highway cruising speeds. The "softer" a tire is the more traction or hookup it will have, but that also means there is more drag from the ground on the tire. If you stiffen the tire up it will handle better at high speeds due to less sidewall folding and it will lessen the drag from the ground on the tire. My question is more about at what ratio do you raise the psi front-back?

 

[buddy3824]

I honestly dont feel that it matters that much... if you want more psi, then put 35-36 in them. i wouldnt go more though. much higher, and the amount of gas you save may not equal the excess rubber you are using...

 

[Cooper-97gst]

I don't think that a difference of 3 psi would make any noticeable difference. I would just run the same pressure in all four.

 

[carvinbassplyr]

I honestly dont feel that it matters that much... if you want more psi, then put 35-36 in them. i wouldnt go more though. much higher, and the amount of gas you save may not equal the excess rubber you are using...

I planned on running 36 in front and either 33 or 36 in the rear depending on if the staggered psi was necessary.