Optimal Tire Pressure?

mlewis67 · #1 10-06-2008, 03:12 PM

Just bought new 2008 X5 4.8i a month ago w/ 20 in. wheels/Sport Package, etc ... recommended tire pressure on door lists 32 psi ... had @ 34 psi for 1st month & just upped to 36 psi ... any comments or suggestions? Prefer a tighter ride, etc ...

mrkbbd · #2 10-06-2008, 03:25 PM

I personally like to run a higher pressure in the back than in the front, about a 4-6 psi difference to make the car oversteer a bit more than it's supposed to, this is not good for tire life though

mlewis67 · #3 10-06-2008, 03:27 PM

thanks ... what do you do? 36 in rear & 32 in front?

mrkbbd · #4 10-06-2008, 03:35 PM

I do anywhere between 36-38 in the rear and 30-32 in the front

youry · #5 10-06-2008, 03:37 PM

I think it is 32 front and 39 rear.

mlewis67 · #6 10-06-2008, 03:50 PM

Someone once told me that they inflate more in front than rear? #1 to support more weight in front (engine) and #2 ~ bigger ratio of rear wheel drive power, so you want the tires less inflated in back to grip road better? You guys ever heard of that?

StanF18 · #7 10-06-2008, 03:53 PM

I believe the 32 front/39 rear is listed for high loads only, or for speeds in excess of 100 mph.

Having said that, I've tried all kinds of tire pressures on my 19" staggered setup, and I find that 32 psi all-around feels "sluggish", with lots of rolling resistance, and does not give optimal steering response IMO. I've settled on 35 psi front/37 psi rear as the optimal cold pressures.

You just need to play around and see what works best for you. As long as you stay between 32 and 39 psi for any given pair, it's safe.

mlewis67 · #8 10-07-2008, 07:38 AM

Thanks Stan ~ agree .. have @ 36 all around now, but will try 36 front & 37 rear .. specially now that we're heading into colder weather in the Northeast.

brian5 · #9 10-07-2008, 08:47 AM

Quote:

Originally Posted by mlewis67

Just bought new 2008 X5 4.8i a month ago w/ 20 in. wheels/Sport Package, etc ... recommended tire pressure on door lists 32 psi ... had @ 34 psi for 1st month & just upped to 36 psi ... any comments or suggestions? Prefer a tighter ride, etc ...

I usually go by what it says it in the Owner's Manual... If look at page 235/236, you can find this info too.

If you have two rows of seats; 32 psi in the front and rear
If you have three rows of seats; 32 psi in front and 35 psi in rear

I did have mine higher, at around 35 psi, but did not notice any difference when I lowered it to these recommended levels. Can't think of a reason that I would not follow BMW's recommendations on tire pressures...

mrkbbd · #10 10-07-2008, 09:31 AM

Quote:

Originally Posted by brian5

Can't think of a reason that I would not follow BMW's recommendations on tire pressures...

I definitely can, here's two: change the handling of the car to better suit your driving style and better gas mileage