[Native_One]

I have a 06 325xi with the factory staggered setup, summer tires...I tried to switch them out with get-flat tires this past year and ran into issues with DSC....

When I first put the new tires on I had no problems. When I had to replace two of them all h#!! broke lose. The DSC would come on during acceleration...two weeks in the dealer and all they could come up with was the weight of the RFT's. The size was exactly the same as OEM tires...

Has anyone heard of this? TireRack has not....

I want to get rid of the RFT's in the worst way...

Thanks

T

[Nikolas]

Originally Posted by Native_One

I have a 06 325xi with the factory staggered setup, summer tires...I tried to switch them out with get-flat tires this past year and ran into issues with DSC....

When I first put the new tires on I had no problems. When I had to replace two of them all h#!! broke lose. The DSC would come on during acceleration...two weeks in the dealer and all they could come up with was the weight of the RFT's. The size was exactly the same as OEM tires...

Has anyone heard of this? TireRack has not....

I want to get rid of the RFT's in the worst way...

Thanks

T

The weight should not matter. I am guessing that since you replaced only two, that the new tires have a slightly larger outside diameter than the two old tires.

[Native_One]

Would the tire diameter be that sensitive? There was about 8 months of wear on them...

Does that mean that all have to be replaced at once?

An engineer that I work with, and former Benz tech, said the system monitors wheel spin based on weight which the lighter tires would be a different equation than the OEM's...

[Nikolas]

Originally Posted by Native_One

Would the tire diameter be that sensitive? There was about 8 months of wear on them...

Does that mean that all have to be replaced at once?

An engineer that I work with, and former Benz tech, said the system monitors wheel spin based on weight which the lighter tires would be a different equation than the OEM's...

I have never heard of an AWD system that monitors wheel rotation based on weight. That just makes no sense, granted I am no engineer though. Depending on how much wear you had over 8 months, yes it can be that sensitive. Generally with AWD, it is good to replace tires all 4 at a time with the same brand and matching diamter if you go staggered. I think the exception would be if the tires have minimal wear. 8 months could be 10,000 miles. On our cars, that could be significant wear on the tire.

[Native_One]

I did have to replace two of my OEM's at one time and that didn't bother the system...

Anyway, thanks - wish I hadn't wasted my money on this car - thousands have been spent replacing these RFT's from nails to premature wear....

[NM_BMW]

I believe the old system would monitor wheel rotation and would determine the PSI by how fast or slow it was spinning. With the new system it actually has a sensor within the tire attached to the wheel and is able to give a more precise PSI reading. Again, this doesn't effect your situation.

The system is very sensitive. If you went with stock tire sizes then yes it probably is that sensitive because the stock sizes are really close to 1% difference. I believe their around .80% difference in OD. The rule of thumb is to not get staggered tires that have a difference greater then 1% of their overall rolling diameter.

What are the stock staggered setup on the 328xi?

[Native_One]

225/45/17 front & 255/40/17 rear

got the vehicle in June of 06...

[Nikolas]

Originally Posted by Humtek

I believe the old system would monitor wheel rotation and would determine the PSI by how fast or slow it was spinning. With the new system it actually has a sensor within the tire attached to the wheel and is able to give a more precise PSI reading. Again, this doesn't effect your situation.

The system is very sensitive. If you went with stock tire sizes then yes it probably is that sensitive because the stock sizes are really close to 1% difference. I believe their around .80% difference in OD. The rule of thumb is to not get staggered tires that have a difference greater then 1% of their overall rolling diameter.

What are the stock staggered setup on the 328xi?

The system we were discussing was not the TPMS, but the AWD and DSC. Changing tire diameters has absolutely nothing to do with the TPMS.

[NM_BMW]

Originally Posted by Nikolas

The system we were discussing was not the TPMS, but the AWD and DSC. Changing tire diameters has absolutely nothing to do with the TPMS.

I understand that, but the way he was explaining it made it seem like he was talking about the TPMS system and got them confused.

[Native_One]

The way that I understand the system to work, and feel free to correct me...the system monitors wheel spin, which will feed the tire pressure monitoring and feed the traction control. The weight of the wheel will affect the monitoring of the spin. Too light on the tire weight, even though the correct size, will make the wheel spin seem faster than it should and thus kick on the DSC. The car would start breaking the wheels and slowing down as if it was stuck in AWD. Let off the accelerator and everything would seem fine. There was no tire slippage and it would do it on hard cornering and acceleration wet, dry or whatever....

[offthewall]

Originally Posted by Humtek

I believe the old system would monitor wheel rotation and would determine the PSI by how fast or slow it was spinning. With the new system it actually has a sensor within the tire attached to the wheel and is able to give a more precise PSI reading. Again, this doesn't effect your situation.

The system is very sensitive. If you went with stock tire sizes then yes it probably is that sensitive because the stock sizes are really close to 1% difference. I believe their around .80% difference in OD. The rule of thumb is to not get staggered tires that have a difference greater then 1% of their overall rolling diameter.

What are the stock staggered setup on the 328xi?

The OEM staggered sizes are

225/45/17 255/40/17 or 225/40/18 255/35/18

both of which only have a 0.2% size difference.

[NM_BMW]

Originally Posted by offthewall

The OEM staggered sizes are

225/45/17 255/40/17 or 225/40/18 255/35/18

both of which only have a 0.2% size difference.

My bad. For some reason I was thinking of the 335 when I wrote that.

[atking23]

all i wanna know is, can I put the style 190 OEM wheel set without having any problems?
cause if there's the slightes chance I will have a problem i wont do it.
this all very complicated to me, do the people at the shops know this for sure? I all just take it there.

[ucdbiendog]

wish i had seen this a couple months ago. I got a set og staggered 17" rims for my winter tires, and put some all seasons on that had an identical OD front to back. But for whatever reason, the fatter tires in back didnt compress as much, so the rolling radius was taller. This caused the DSC to trip. I replaced that back tires with the same size tires that are used in front and it fixed the problem.

[SGxi]

I thought on a AWD car, you should always replace all 4 tires at the same time?

[JaysBlueE92]

good thread..this seems to be a hot topic. Id like to hear from E92 xi owners on KW V3s what there settings are and offsets for 19 inch wheel and tire combos

[flame51]

im a little confused.....is this problem only with a staggered setup? for example i was gonna switch to 235/35/19 all around from the stock 225/45/17 rft's. would this issue affect me? also what if i have spacers running in the back does that change anything?

[GregL]

Originally Posted by flame51

im a little confused.....is this problem only with a staggered setup? for example i was gonna switch to 235/35/19 all around from the stock 225/45/17 rft's. would this issue affect me? also what if i have spacers running in the back does that change anything?

You'll be fine, even with the spacers. I'm running 235/35/19 all-around on staggered rims (8.5F/9.5R) for my summer setup.

[rmercedes6]

i have 20 x 9 with 245/35/20 in the front and 20 x 10 with 275/30/20 in the back and i been having this setup for 2 years now and never had any problem.
I luv my 325xi

[stevenzx]

Originally Posted by halB

235/35-19 F 265/35-19 R IS NOT OK FOR Xi! F/R speed difference is 3.2%. You will definitely kill your transfer case clutch pack.

Even 235/35-19 F 265/30-19 R is not the best. F/R speed difference is -0.8% (rear tire being smaller). Too close to the 1% limit for comfort.

If you have to have 19" staggered in an Xi, you should go 235/35-19 F 275/30-19 R. Speed difference is 0.1%. Just make sure you have the correct offsets so nothing will rub.

FYI - The factory set-up of 225/40-18 F 255/35-18 R has a speed difference of -0.2%.

For the OP - Don't drive your car until the tire size issue has been resolved. With 2.5% speed diference in your setup according to my calculation, you are playing with fire. If you smell smoke, it will be your clutch pack burning!! (You won't exactly smell smoke but you know what I mean.)

hi bro, do u think the front rear difference will make rwd tranny fail? i am using 235 35 19 on the front, 205 40 18 rear. stock is 205 50 17. sometimes i get into limp mode. i drive 2008 130i.

[bennye90]

Originally Posted by stevenzx

hi bro, do u think the front rear difference will make rwd tranny fail? i am using 235 35 19 on the front, 205 40 18 rear. stock is 205 50 17. sometimes i get into limp mode. i drive 2008 130i.

idk why you would run that setup in the first place..

[stevenzx]

Originally Posted by bennye90

idk why you would run that setup in the first place..

i am doing widebody project now. just finish the feont fender and the rear fender are still stock.