Sponsored by The Tire Rack

[BigDaddy2]

First post, happy to be here.

I'm looking/researching my wheel purchase. Would a staggered set-up work OK with AWD? I'm thinking that I should keep the same size tires all around.

I have 17" on my 300xi and am looking to go to 19" for the summer.

Thanks!

[TEFLONJ]

i have 19in stags on my 2006 325xi and there fine.

[mds82]

same here, 325xi with staggered setup, 225/35/19 front, 265/30/19 rear. works great for me.

[therat]

just ordered some 19s 8.5/9.5 w/ 245/35 and 275/30s..can't wait til they get here

[mds82]

I wouldnt go with those tires!!!! the 245/35 had a diameter of 25.8 inches and the 275/30 has a diameter of 25.5 inches. Thats a more noticable difference then i would recomend. You should go with a 235/35 front because that is a 25.5 diameter. I dont know if your drivetrain will get screwed up because of the different rolling diameters front to back. I would really think about getting the 235/35 frnont.....

[mds82]

check out the specs here. this is for the goodyear eagle F1, but they are pretty much the same for all i think
http://www.tirerack.com/tires/Spec.j...Eagle+F1+GS-D3

[therat]

yeah..i was aware of the difference in wheel diameter..but other members have told me that you can't notice the difference when they are on..but in terms of affecting the AWD system, that I am not sure..do you are anyone know if this will mess anything up?

here is a link of one member w/ this setup, but no xi.

http://www.e90post.com/forums/showthread.php?t=21720

[BigDaddy2]

That's the basis of my post. Will slightly different ODs be a problem with the AWD on the xi?

It's more for looks anyway. I can't imagine that the little extra contact patch in the rear of an AWD car makes a difference.

[Getagrip]

FYI, BMW offers a staggered 18" option for the Xi and the diameters are .1 inch difference front to rear.

BTW, doesn't the X5 have a staggered set-up in one of the trim levels?

[foofighter]

usually most AWD system will allow for a tolerance of 5% difference from wheel to wheel as this accounts for things like if you get a flat and have to run a spare you'll still be able to drive it and not fry your diff.

Just out of curiousity, the xi is it rear wheel biased?

[Getagrip]

Originally Posted by foofighter

usually most AWD system will allow for a tolerance of 5% difference from wheel to wheel as this accounts for things like if you get a flat and have to run a spare you'll still be able to drive it and not fry your diff.

Just out of curiousity, the xi is it rear wheel biased?

Yes, it is rear biased. Even more so than the E46 Xi model. The old Xi had front 38, rear 62 constant split. The new one (Xdrive) drives the rear and just apportions power to the front as need. Maybe this is why they can do staggered now.

[ep609]

Originally Posted by BigDaddy

That's the basis of my post. Will slightly different ODs be a problem with the AWD on the xi?

It's more for looks anyway. I can't imagine that the little extra contact patch in the rear of an AWD car makes a difference.

there is probably no difference with the AWD but with the ABS and DSC.
It wont get the right data anymore. Could be a problem.

[therat]

thanks everyone for the input...i think i'm might go it safe and change to 235/35 F and 275/30 R, since there are many potential things that can go wrong w/ the AWD system that no one really knows for sure

[mds82]

awesome, lets see some pics once you get it in. i wana see if the car looks as high as mine

[Getagrip]

My tires just came in yestersday and I mounted them up on my 18" CSL reps. Front 8.5"@40mm offset and rear 9.5" @45mm offset. Tires are Kuhmo Ecsta SPT 235/40-18 and 265/35-18. The rear tires mounted on the rear wheels a lot easier that i had expected. The fronts were a little tougher.

Anyways, I was afraid i was going to need spacers to keep the front are rear tires from rubbing the inside. Thet fit perfect and they don't look too tucked.
I initialized the FTM system before my testdrive and drove about 30 miles. All is ok and no strange 4WD noises and no DSC/FTm/Xdrive errors.

I post pics in another thread a soon as I get some time.

Next is springs when the they become availabe.

[BigDaddy2]

Great! I'm looking forward to seeing them.

[BMerDRMer]

Originally Posted by Getagrip

Yes, it is rear biased. Even more so than the E46 Xi model. The old Xi had front 38, rear 62 constant split. The new one (Xdrive) drives the rear and just apportions power to the front as need. Maybe this is why they can do staggered now.

I've been reading and participating in these posts for a while now ........ never seem to get a consistent answer on front to rear power apportionments ........ I had thought 75/25 Rear to Front in all conditions until slippage, and then fully variable .....front to back and side to side ...... anyone know the real answer to this??

[Getagrip]

This is the best I could find from what BMW says:

"Driving torque is always transmitted to the
rear wheels, and most of the time to all four
wheels."
....still pretty vague.
As for side to side, the front and rear diffs are open, so the brakes control side to side at low speeds. A cheap way out of a LSD

[BMerDRMer]

Originally Posted by Getagrip

This is the best I could find from what BMW says:

"Driving torque is always transmitted to the
rear wheels, and most of the time to all four
wheels."
....still pretty vague.
As for side to side, the front and rear diffs are open, so the brakes control side to side at low speeds. A cheap way out of a LSD

Thanks get a grip ....... maybe that new perfromance center in the "artic" will start really "educating" us in a year or two .........

[ska///235i]

Can we see some pics please

[Getagrip]

Originally Posted by mds82

awesome, lets see some pics once you get it in. i wana see if the car looks as high as mine

Pics are up!
http://www.e90post.com/forums/showthread.php?t=23244