2003 330i 18 Inch wheels (225 front, 255 rear) - tire pressure--help!!

[nicholasdj]

HI everyone, I need your help.

I have a 2003 330I witht eh 18 inch alloy wheels (factory installed), and I also have a DINAN cold air intake system and reprogrammed computer and transmisison is that makes any difference to tire pressure.

the interior door panal says i should run 32F and 38R with up to 4 poeple and 39F 46R with 5 peopel and full trunk. My car was perfect until some idiot at a gas staion changed my pressure, when i just asked him to check it at let me know, grrr. and since then the car has either felt loose , especially at higher speeds, like not gripping, or other times (when i chnage the pressure,) feels too soft and sluggish.

I have one of those digial BMW tire gauges and i used it recently to set the tires to 32F and 38R. however, the car does not feel nearly as good as a few months ago. Can ANYONE give me soem suggestions, or offer some helpful advise? should i get a different guage? anything that can help will be appreciated,,,thanks!!!

 

[Kirby]

Is it still mushy? Can you describe how it used to feel (front very responsive, neutral/even handling, applying power in a corner made it turn better or worse, etc.). and compare to how it feels now? How about sound/road noise? Is the road noise more noticeable now (higher tire pressure)?

Other than this, all you can do is systematically change pressures until you get back to where you were. You might take it like this:

35F 35R
35F 38R
38F 38R
38F 44R
42F 44R

I wouldn't go any more than 6 lbs difference front to rear, and never put less in the rear than what is in the front.

 

[stf05330Ci]

If you have an '03 chances are you've changed the tires out by now. If you have and didn't get the same tires that were originally with the vehicle, then you should check the sidewall of the tires to ensure that your door information sticker is correct. Tire pressures vary with different tires. Let us know what you find out.

 

[jrt67ss350]

If you have an '03 chances are you've changed the tires out by now. If you have and didn't get the same tires that were originally with the vehicle, then you should check the sidewall of the tires to ensure that your door information sticker is correct. Tire pressures vary with different tires. Let us know what you find out.

Yes, but the tire pressures listed on the tires are the MAX tire pressures permitted for that tire. You should never run MAX pressures - always use the tire pressure values listed on the door sticker or owners manual as a guide (unless you drive a Ford Explorer - ).

 

[nicholasdj]

well, this is what i tried

HI Kirby, thanks for your reply,
well, before, the car felt very firm, but not harsh, and there was almost no hessitation in accelerations. aslo even when going at slow speeds you coulkd feel each tire gripping the road. yes, u are correct, accelerating into a turn did make it feel even tighter.

now, at 32, 38, the car feels a lot more much, and just loose, exspecially the steering and the front.

does this give u a better idea to help me?

and to the others, hmm, car only has 12000 miles, and the treads look perfect, michelin pilot sport.

 

[jaime-330]

How many miles have you run with those tires already? [???1] Have you rebalanced them at all since you got the car? If you have not, you may need new tires, or if they still look ok may be they need to be balanced.

 

[Average Jae]

Welcome to our lil bimmer corner Andrew.

when you are checking the tire pressure, make sure the readings are COLD. meaning you take them before you drive out in the morning in the shade. (being outside w/ sun will mess up the readings as one side will be warmer than the other.)

i usually run 32 in the front and 36 in the back. the most important thing is to keep the values of left and right side equal. i run the psi up in the winter as temps go anywhere btw 40s to 0 in a hurry around here. (and its too freakin cold out to pressure check every 2 weeks..

you'll get more traction at lower psi but at the cost of lower mpg. if your tires have too much air, you'll get better milage (less contact surface) but it seems dumb to me, since it'll handle worse and sort of kills the point of having fat tires in the first place. and balance your tires every 5k? since you can't rotate them, just balance.

also remember that with each 10 degree F drop in temp, you'll lose 1psi, and vice versa gain 1psi per 10 F rise.

 

[nicholasdj]

hi jae, i agree with u completely,
more grip and performance, with less mpg, is just fine with me.
but i can seem to find the compromise between grip, and the car nopt feeling soft and mushy...

 

[robo1]

I just bought a sweet 2004 330ci and have had four dealers tell me four different things related to correct tire pressure....could someone help? I've got Michelin Pilot's with P225's in the front and 245's in the back....I've been told that 32 in front and 35 in back is ok although the door decal says 32 and 38....what gives here?