[Toomstone]

Ok so don't tell me to search because I already did. On the tire the max inflation is 44 psi... so what would be recommended? I just got out the compressor and went 36-37 on the fronts and 39 on the rears?

Toomstone

[stressdoc]

Wrong forum (should be moved to tires)

Recommended pressures are different for each type of E9x and ZSP and conditions. For my car (E90 335 ZSP) the manual (p.119) suggests 33 front, 38 rear for around town low load driving, but increase up to 39/45 for high speed heavy load.

That said, you may wish to adjust tire pressure to fit your particular driving needs. For example, increasing by a few lbs to improve gas mileage and handling, or increasing pressure a little bit in front to reduce understeer, or increase a bit with high speed or heavy load (3 or 4 passengers). Also, check the wear pattern on your tires regularly and adjust pressure accordingly.

[Lassaxi]

Originally Posted by Toomstone

Ok so don't tell me to search because I already did. On the tire the max inflation is 44 psi... so what would be recommended? I just got out the compressor and went 36-37 on the fronts and 39 on the rears?

Toomstone

As with almost any other new car, look at the placard inside the driver's side door.

[Toomstone]

my bad... I was going back and forth between the sections and accidently posted it in here.

Toomstone

[MrSteak]

If the tires are new and undamaged, inflate em at least 5+ over max psi. (So if the side of the door says 36, and the tire says max psi 44..... go 49!) But if you've driven around and beat the tires down already, inflating them 5+ ovr max psi could emphasize any preexisting problems.)

You'll feel a little more road, but overall the tire will be safer, stronger, and maintain better contact in rain. Cause when a tire is rated "Y" which is rated up to 186mph, that 186 speed is the max performance, and you'll need max pressure to achieve it. (BTW, learned all this @ Stunt Driving School. The tire portion of the class was very good.)

[stressdoc]

Originally Posted by MrSteak

If the tires are new and undamaged, inflate em at least 5+ over max psi. (So if the side of the door says 36, and the tire says max psi 44..... go 49!) But if you've driven around and beat the tires down already, inflating them 5+ ovr max psi could emphasize any preexisting problems.)

You'll feel a little more road, but overall the tire will be safer, stronger, and maintain better contact in rain. Cause when a tire is rated "Y" which is rated up to 186mph, that 186 speed is the max performance, and you'll need max pressure to achieve it. (BTW, learned all this @ Stunt Driving School. The tire portion of the class was very good.)

If he has rfts over-inflation will make the ride unbearable. And the wear patterns can make for a shorter tire life.

[japac1]

Just like you'd read in every thread about this very same question: Use the recommended manufacturer pressure located on the placard on your driver's door...

[MrSteak]

Originally Posted by stressdoc

If he has rfts over-inflation will make the ride unbearable. And the wear patterns can make for a shorter tire life.

Well, I won't argue about the ride being worse... but that’s the only drawback. Maintaining a higher tire pressure will only increase the tire’s life.

The “recommended” tire pressure on the side of the door, is comfort bullshit. The weakest part of the tire is the sidewall, and the only way you’ll strengthen it is by maintaining a higher pressure. (And like I said before, it helps in all other aspects… tread wear, wet traction, life, etc…)

[davig]

Originally Posted by MrSteak

Well, I won't argue about the ride being worse... but that’s the only drawback. Maintaining a higher tire pressure will only increase the tire’s life.

The “recommended” tire pressure on the side of the door, is comfort bullshit. The weakest part of the tire is the sidewall, and the only way you’ll strengthen it is by maintaining a higher pressure. (And like I said before, it helps in all other aspects… tread wear, wet traction, life, etc…)

Not at all-the middle of the tread will wear prematurely and handling will suffer. This advice probably was OK for bias ply tires.