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-The Mouth-
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Discussion Starter · #1 ·
I have a 2002 325i SP. I was wondering what the tire pressure should be or at least what I should start at. The setup is
225/45R-17 with style 96 wheels all the way around no off set.
Can anyone with the same set up give me their input. Right now I have 35 PSi all the way around.

:dunno: :dunno: :dunno: :dunno:
 

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Rest in peace, Coach
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Look on the door jam.
 

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-The Mouth-
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Discussion Starter · #4 ·
checked jam but it reads like brail. It has my tires pressure for the front but not for the rear. Yeah Pete it's the shimmy. I know I just need an alignment but I put the pressure up to 35 al around last night and the car corners MUCH better.
 

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Hi
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3seriesbimmer said:
checked jam but it reads like brail. It has my tires pressure for the front but not for the rear.
MUST have both front and rear pressures on the door jam. Read the owner's manual too, you paid for it when you bought the car! :D :D :angel:
 

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The door jamb [edit] can be a little misleading, since it gives pressures for max load (well, mine does anyway). Pg. 24 of TFM gives a much clearer table to go by. According to this chart, with 225/45/17 Z rated tires all around, fronts should be 30psi, rears 35psi. You can also check the tire manufacturers website for pressure rec's.

I personally find that 30psi front is too soft. Michelin Pilots tend to understeer a bit anyway. So I usually run 32 front, 36 rear. I have found this is optimal (IMHO) for about 80% of my driving. Pushed hard, the fronts still seem a bit soft, and understeer only in very hard cornering. Just this morning, I took the exit for work off 128 (which is a VERY sharp hairpin corner - the road nearly doubles back on itself), and floored the gas to try to get the rear around. No go - the fronts squeeled though. I thought that was odd because with 36 in the rear, I should have more oversteer...
 

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can someone explain understeer/oversteer. I too have been trying to determine the "best" tire pressure for my 330i sp. thanks.
 

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jester76 said:
can someone explain understeer/oversteer. I too have been trying to determine the "best" tire pressure for my 330i sp. thanks.
Understeer is when the front tires lose traction before the rears. This is generally described as plowing. Basically, when you go into a turn, you will find that you have to turn the wheel far more than you would normally turn it when you're going much slower. Oversteer occurs when the rear tires lose traction first. Basically, the tail swings around.

hth.
 

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