[RevC]

Greetings! maybe someone could help me out here. I had my wheels changed over from a winter to summer set. The winters were 19 by 8.5/10 the only diff with the summers are the rear width is 10.5. The tire sizes have went from 235/275 to 235/265. The real issues started as soon as I drove home from the shop who changed them out for me. It felts as if the transmission was completely slipping out of gear and jolting on acceleration. This happens throughout the pegs. It's apparent it's either something with a mount to me however the shop I took it to after informed me the transmission software needs to be reprogrammed and "it is throwing off your gear ratios because you went with wider wheels which are staggered on an AWD car". Personally I don't know the validity of this statement and am hoping somewhere here could offer some advice or insight, thanks! Rev

[Kalidian]

O.o ...

I literally just swapped over to my summers (same tire sizes) 2 days ago and I've had no issues. I did a ton of research before buying summer wheels for my xi and I've never heard about having to "reprogram the transmission software". Unless I'm missing something big, I think that's his way of saying "I don't know wtf is going on". To my knowledge, having staggered wheel widths won't affect the xi system as long as the rolling diameter remains the same front to rear, which means it comes down to having the appropriate tire sizes, which you seem to be okay on with 235/265, assuming 35/30 sidewall ratios on 19's.

Anything light up on the dash? First thing you should check is the tire sizes, make sure they're within that 1% tolerance for differences in diameter.

[tareemaa]

What are your ratios for the side walls? I think you are outside the exceptable range for the xi system, ideal is 235/35/19 and 275/30/19, that its actually a closer rolling diameter than the stock sizes, if your rolling diameters are off by I believe more then 1 percent than your gonna run into problems, and ultimately mess your car up, I'd advise to switch them out asap

[ska///235i]

+1

[SS e93]

Hey is it similar to my issue?
http://www.e90post.com/forums/showthread.php?t=829298

I did the SAME EXACT thing. went from my stock square setup, to a staggered 235/265 setup this year. I ran 235/275 last year and didn't have this problem.

In theory the 235/265 setup is 0.89% difference. I think most others don't run into the issue we are having mainly because there are so few 6mt/xi owners in general.

[Kalidian]

It's true, mathematically 235/275 is the ideal setup for our xi cars, with virtually no difference in the front/rear diameters. However I think a lot of xi guys have run 235/265 at some point with no problems. I'm doin it now and so far so good lol.

When it comes time to replace my tires though I'm definitely rolling with the 275's in the rear just to be safe.

[RevC]

Hmm profiles are 35/30..f+r.. I did have no problems with 235/275 but am def having problems now with 235/265. No idea what's goin on, the rolling diameters should be within range too.

[RevC]

I do have the bt, anyone know how to reset the transfer case?

[kalee]

Im having the same problem and im running 235/35 and 255/30. Its not slipping too much but i can feel there is something wrong

[tareemaa]

same issue, the rolling diameters are off, a reset may work but that doesn't alleviate the fact that your adding stress to the powertrain.

[kalee]

My rolling diameters are under 2% is it still bad?

[RevC]

They say less than or equal to 1%..what You're running I could confirm is DEF bad LOL. They are way off. Bump..chicken n rice for whoever can help

[Kalidian]

That's a headscratcher. I'm running 235/40, 265/35 (basically the same setup) and I don't feel like anything is wrong on mine.

Is it just the transmission acting up? Are there any other symptoms like vibrations or weird noises or anything?

edit: and kalee, if you keep rolling on 235/35, 255/30 you'll ruin your transfer case/transmission pretty soon. Easily ~5k in repairs.

[RevC]

Yup just the trans and gearbox

[T0NE*F32]

maybe it has to do with the 265 tire being stretched on a 10.5 wheel?? Correct me if Im wrong but when stretching doesnt that affect the height of the sidewall resulting in diameter change..

[RevC]

Originally Posted by T0NE*E60

maybe it has to do with the 265 tire being stretched on a 10.5 wheel?? Correct me if Im wrong but when stretching doesnt that affect the height of the sidewall resulting in diameter change..

Hmm they're not really stretched at all, dws runs pretty wide but u could have a point here! I've also reset all values on transfer case tab on bt tool and issue still persists

[T0NE*F32]

you didnt list tire sidewall size.. 235 / 265 by what?

[RevC]

Oops. 235/35/19 and 265/30/19 continue dws

[T0NE*F32]

those are the most common sizes people run with no problems on an xi. not sure what the problem is.

[T0NE*F32]

try switching out the rear summer set with the winters and see if that problem persist. I

[RevC]

Will do. I've talked to a couple people whom have had this problem with a 265 rear and the problem was fixed when they switched to a 235:275 set up. Weird. I mean I def had no problem with the winter setup.

[Kalidian]

Good point about the possible diameter difference resulting from stretching the 265's over 10.5 wheels. I think that may be it.