Optimal Tire Pressure?
 

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

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

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

I think it is 32 front and 39 rear.

Optimal Tire Pressure
 

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?

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.

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.

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. :p:

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...

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

Well, I'm assuming that BMW's recommendations are based on their testing of the best tire pressures for the particular X5's. Which is WAY MORE testing than any one of us will ever do.

How would you change the tire pressures so it would suit your driving style? I'm not talking about if it was to be driven on the track (as X's are not typically used as track cars). I know you mentioned oversteer (in an earlier post) but isn't that more important for a high performance rear wheel drive car? Don't we want the X5's balance to be more neutral?

On the gas mileage option, I'm personally far more interested in road grip than insignificant gas savings. If I wanted to save gas, I would have to change my driving style.

Well I know how I generally enter turns and there are particularly a few turns that I like to go around really fast, so I want my X to be able to be able to take those turns at the fastest speed possible. Furthermore, BMW has the car setup for it to be easy to handle for any driver, and therefore it isn't neutral, that thing will understeer significantly. The other thing is I have tracked a 4.8is in the past, so I guess I'm not the typical suv driver. Oversteer isn't particularly more important in one car versus another, high-power rear drive cars are typically more prone to oversteer due to the power but on virtually every stock car it is nearly impossible to oversteer the car by merely its handling characteristics due to safety precautions the vast majority are intentionally tuned to understeer. The part about what "we" want does not go in line with my point, you can slightly alter the car to cater to your needs / wants. You may enjoy a very neutral car, or a very twitchy car, or a boring car, it's all personal preference and what you're comfortable with.

Interesting response -- you're probably right about the understeer.

I've quoted the last bit. As my son would say, "did you just diss me"? :yikes:

no, I definitely was not intending any disrespect, it was a collective you not a you personally

:rofl: I wasn't concerned about it one bit. Was just :stickpoke