Tire size programming, Please Help!
 

Does anyone know if it is possible to update the ECU to a different tire size. Installed New tires on MY 07 Sport pack and now getting an intermittent driveline noise at various RPMs and road speeds especially during cornering. Switched to Pirelli P-Zero Nero MS 245/45 18 front, 275/40/18 Rear. The tire diameter is 3% shorter than with stock tires and I'm sure the driveline noise is caused by Computer Thinking that I have taller tires. It is a weird noise that sounds like when the stability control kicks in. No dashboard lights though.

I go into more detail about this in my Bimmerfest thread. Here is a link

http://www.bimmerfest.com/forums/sho...d.php?t=188710

Any thoughts?

:wavey::xoutpost::wavey:

don't you set the neutral tire pressure by holding down the tpm button?

tire pressure?, yes. Tire Size? no.

wheres the sound coming from...from outside like from the tires or inside the X3 like when u push the lever to signal...it has the clicking sound?

The sound is coming from the differential, transfer case area a bit to the rear of the car. And it is definitely computer related. Meaning the car is telling the DSG or X-Drive to do something. I just don't know what it is telling it.

From the looks of your sig you have different wheels on. Which tire combination are you running.

actually those are the rims i want on my x3. I currently dont have a pic of my x3 so im using that for now...

I went from 17" to 19" and no problem. Nowhere in the manual does it say to reprogram anything other than reset the tire pressure monitor system.

Which tire size 19" did you switch to.

007,
I've re-read your initial post on BimmerFest a couple of times and here's
my 2Cts:
-yes, different tires and different size tires can give considerable variance
in "feel", road noise, handling, turn-in responsiveness, etc.

But, I think the drivetrain/gear whine noise is coincidental, unrelated or,
is tire noise with that specific fitment and/or something else is amiss.

-the tire size rolling diameter "difference" is nil, for practical purposes,imo.

I've gone from punky-azz little 15s to Plus1 ++ 16s on my wife's crappy
Honda CR-V, with no problems; I've gone from oem 18s to big 132 staggered
19s on our X with no problems.

It seems like you are hunting for a problem or overly concerned about
the potential speedo diff: it is no biggie. As for "reprogramming/reclibrating"
the electronics, I must be missing something.

Slap on the tires, in the sizes within reason, you like, and go drive and
enjoy your X.
GL,mD