Tyre pressure

[Alan Smithee]

Originally Posted by Howiedds

any advice for non rft? i was running recomended pressures psi( 32F/35R) on my toyo proxes STII-20 inchers, but after 1000 miles, the front seems to have some abnormal wear on the outside tread.... should i inflate 35psi even front and back. Car load is generally just me and wifey, 160lbs + 100lbs.

I run 35 PSI all around in my 20" Toyos. What little wear there has been in 10k miles is even, and that is with aggressive cornering and no Adaptive Drive.

[bren3085]

Originally Posted by Ben_XI

I have 20" Bridgestone Dueler HP Sport RFTs and was running 36 psi all around. But I noticed this doesn't provide the best "even" tread wear. So, I changed it to 41 psi all around and noticed an improvement. Went to get a new alignment for "even" tread wear and they recommended 40-44 psi.

Ditto, I use to run 35 psi and found uneven tread wear..i upped it just a little to around 38 front and rear and this set has lasted significantly longer

[Howiedds]

Originally Posted by Alan Smithee

I run 35 PSI all around in my 20" Toyos. What little wear there has been in 10k miles is even, and that is with aggressive cornering and no Adaptive Drive.

I just increased to 35psi @ all corners...lets see if it helps.

[r6vr6]

Originally Posted by Howiedds

the car is new, i removed the rfts off immediately and mounted the toyos...do i still need an alignment?

I don't really drive aggressively...ill take some pics when i can

Keep in mind that the alignment warranty coverage is 2000 mi or something ridiculous. If you think the alignment might be out of spec you should get it checked sooner rather than later if you have any hope of getting coverage for the alignment. They may find it to be within spec but I would then have them then align it to more tire friendly settings if you are concerned with wear. My wife's toe was 0.9 & 0.7 deg from the factory. I had it set to 0.1 deg. I also had pretty severe rear wear from the negative camber. It was out of spec (as measured by the dealer) from the factory but it was more positive than it should have been. I actually had them go a little more out of spec to help with the wear. The handling feels nearly identical but I don't drive it like I do the M3. Wife hasn't complained about the handling so I guess that is what matters.

[Howiedds]

Will the dealer try to blame the tire change (rft to non rft) as the problem? Swapping to different tires wouldn't mess up alignment right? Just want to make sure, to me it seems like it wouldn't but maybe somebody knows more...

[r6vr6]

Originally Posted by Howiedds

Will the dealer try to blame the tire change (rft to non rft) as the problem? Swapping to different tires wouldn't mess up alignment right? Just want to make sure, to me it seems like it wouldn't but maybe somebody knows more...

I wouldn't put it past a stealership. Swapping tires will have zero effect on the alignment (angles) but it could affect steering wheel pull \ feel etc. (felt force needed to keep the X5 going straight) A poor alignment or odd tires can feel very similar in respect to vehicle pulls.

[Howiedds]

i would go to dealer, but its in NJ...dunno if its worth it right now, burning up the diesel (fuel shortage) i have in the tank right now... ( local dealer has a bad track record, and they treat customers that didn't buy the car from them like crap)

However car doesn't pull left or right, feels solid and straight, just a little abnormal looking wear on the outer edge of the tire, which may have been attributed to the 32psi it was set up as at the shop that swapped my tires...

[ard]

^^ Couple of things...

1. While "Pulling" is an indicator of an alignment issue, NO pulling is NOT PROOF THE ALIGNMENT IS GOOD. **THE** most common cause of excessive tire wear is too much toe.

2. Listen to the tire shop if you'd like, but recognize these are guys are generally high school educated. (Im not being a dick, it is just that for the most part the folks that work the front line of auto services are not experts...)

3. An alignment is $100. New tires are what, $1200. Do the math. Dont use a BMW dealer.

IMO

[grey]

Thanks to all your comments. U have provided quite a lot of useful information here.

[grey]

Originally Posted by brian5

Here's the detail from the 2008 X5 Owner's Manual that says
1. 32 psi in front and
2. 35 psi in rear
for all 20" wheels for X5's with third row (whether 3.0si or 4.8i and with or without sport package).

If you only have two rows of seats, it's 32 psi all around...

This is great, thanks