What tire pressure do you run?
 

I've been running at the pressures on the data plate (39 all around if I recall). The ride seems really harsh to me. Tires are Michelin Latitude Tour HP 255-18 no-seasons. (Which, by the way, absolutely suck in snow, slush and ice). I have the sport suspension, so I expect it to be firm, but it just seems a bit rough.

I'll probably play around with reducing the pressures a couple pounds to see if it helps but I was curious what others are doing.

Follow the plate on the door, 32/33 psi cold, as best I recall, for my 18" 255s [Conti DWS in winter, Cooper Zeon summers]. If you are running 39 psi, that and the tire type might explain it.

I go with 35psi all around.

Running 35psi front and 38psi rear.

My plate says 33 front and 39 rear. '04 4.8is That's what I'm running too

32 front and rear. Increased to 35 rear when fully loaded (4 people plus luggage, or equivalent luggage load).

Looking at the 2006 owner's manual (the 2004 manual won't load) I see 32/33 all around, even with a full load. the 39/39 figures listed are for four people plus luggage, only when travelling at sustained speeds in excess of 100 mpg. Even at those speeds with four people, it calls for 32/32.

Here's a pic

Here's another pic showing the distinction between cruising under 100 mph and cruising over 100 mph.

I usually follow the plate on the door .

32F/38R here

I have noticed faster center tire wear in the rears. Thinking of moving to 32/35.

Besides the one or two posted here, what PSI are you owners of the 4.6 and 4.8 running?

I run 32/32. Rarely do I have more than two people in the car, and luggage wise nothing more than a 60lb dog or snowboard gear.

32/39 is with the max load of 5 passengers + luggage.

For an empty car, you and a passenger, the tire pressures should be 32/32. We should ignore suggestions for speeds in excess of 100 mph because who is going to fully load their car with 5 passengers and luggage and do 100? Seriously.

If the second chart is to be believed, the 3.0 can't even do 100 with a full load.

If your tire pressures are too high, the center section of the tread will wear faster than the outside sections. If the pressures are too low, the outside sections will wear faster than the center. Alignment will lead to one or the other outside section wearing faster, tire pressures will lead to both outside sections wearing faster.

Check the range of inflation on the tire. Inflate the tires within that range that results in the best combination of handling, ride, noise and tire wear acceptable to you. The combination can be different from other brands and input here as it depends on how you drive.

If the tires don't meet your minimums go to another tire the next time you need them. Most of the time the priority that is most difficult to get to acceptable is inside tire wear when the X is within alinement specs.

The best way to get to or closest to minimally acceptable tire wear is to reduce caster and negative camber. Bear in mind that your minimum requirement for handling may be exceeded before you get to acceptable tire wear.

I run 32/32 as per the placard on the door.

I checked my pressures lastnight, there was about a 3psi difference between FL and FR.

Rears had lost a couple of psi. Car was cold so not too alarmed.

Went to the service station to top them up, and immediately noticed an improvement. Not only did the car ride more confidently, but it eliminated a slight shimmy I was experiencing under light braking from speed.

So I guess pressures are more important than I gave credit for.

(Note: I have brand new LCAs, balljoints and caster arms but admittedly need an alignment)

The OP has a 2004 model, and the owner's manual for that year did not differentiate based on driving speed. In 2006 BMW changed the owner's manual (and the car and tires were still the same, so it was just new improved info I presume) so that they differentiated between normal speed and high speed driving. I would take advantage of the newer information if I had a 2004 model, even if my owner's manual didn't differentiate. That means that since we are unlikely to be driving over 100 mph in North America, that there is no need to go up to 39 psi ever.

Fully agree that with anything up to 4 passengers, it should be 32 anyway.

And the 3.0 does fine. The chart for that one is on the previous page of the owner's manual.

40 psi all round on 255/55r18.

Numerous tyre shops over the years have always suggested higher than the car placarded values for every car/tyre I have had.
For this size tyre they suggested 38 psi all round.

I have tried everything between 32 - 44 psi.
32 psi as the car placard suggests, is just too low for my liking.
I think they suggest this as it is probably the most comfortable.

I find 40 psi the best for me, wearing evenly and very comfortable.

I stick with 32psi all around unless towing on vacation, then I bump up to 34psi at all four corners for a little more stability. I'm running Yokohama YK580 tires in the 235/65R17 size.

2002 X5 3.0 273,870 miles
2004 325i 118,000 miles (also at 32psi Fr&Rr, YK580 225/50R16)

Interesting all been ok at the higher pressure of 34? i run 33.4 all round (or 2.3 bar instead of the placards 2.2 suggested) and still those fronts look like they are bulging and of course they are weighted down by the lump of a 3.0d engine, but it annoys me seeing them like that.

32psi all around on e53 and e70. Tires wear evenly.

My 3.0d does that too - a few times I've been concerned enough to actually get out a gauge and check the pressure, as the front tyre bulge looks very alarming. It's acerbated by the level of the ground it seems...

But they are fine. I have always run 32/32 but have gone to 34/34 on the new tyres I've just fitted as the sidewalls seem slightly softer than the older tyres I had on.

Hey wpoll all good? Yup when i park one side on a kerbside and look at the tire on the side of the road taking the weight i always think i am nearly flat....as for my slow air leak gonna give it few days and see....aint rocket science i will locate the loss eventually

For handling purposes, when aligned properly, x5s, for that matter all BMWs, will have enough negative camber to wear the inside of the tires, especially the rears. Some align for little or no negative camber to correct the inside wear. Reducing negative camber reduces handling limits and regular driving characteristics, one may or may not care. Significant over inflation might offset some of negative camber wear though there will be a noticeable change in ride quality.

Tires that are the correct size for a vehicle can have different specs for sidewalls and tread, softer or harder. Soft sidewall tires can appear under inflated when they are not. The wear pattern can change due to under inflating. Over inflating, unless extreme. does not, though it will reduce handling limits and regular driving characteristics. The impact of correct, over or under inflation varies by driving style and outside temperature.Over inflation can improve mileage.

Unless one is loading the back with a ton of bricks and driving across country there is no need to adjust inflation. Depending on the tongue weight of a trailer, increasing the rear tire pressure will help if the trailer starts swaying.

Over the years of ownership, I have purchased several different brands and model tires. If or how I adjusted inflation varied. There is no constant set of parameters, no one 'size' fits all certainly not from one X5 to another. I align to the max negative in spec degrees and accept the tires will always wear out on the inside.

I run Michelin Latitude Sport 3 in the summer, 255/50 R19 + 285/45 R19; Nokian Weatherproof SUV 235/65 R17 in Winter. Usually just me in the car, 32 psi all round.