Staggered wheel set up and X Drive

[gregdestep]

Been looking to do a mod and get new wheels and tires.

Spoke to a contact at local dealership and he said not to do it - it will ruin the x drive. Will end up dropping $8k on a new transmission.

He said if you want that look, just buy the M.

Is this true? Will having bigger wheels in the back mess up the x drive?
If so, is the solution just getting spacers in rear so they "appear" to be bigger tires?

Thanks - I did try to search through threads but didn't find anything that addressed this directly. When I type in my 2016 F15 x-drive 35i into BMW's site, it pulls up wheel options and the rear is larger. So I am wondering if I'd be good.

[sj22]

Not true at all. Hundreds of people in this forum literally are running staggered and bmw sells them officially when you order a new car. You dont get a different car just because you ordered a staggered setup.

Here is the thing though - make you wheels are OEM spec, tires are new and star marked since the x drive is very picky on mismatched sizes. Doing that will mess up your differential (not transmission).

I have oem 21 wheels and oem star marked tires. Handles better than square actually.

[gregdestep]

Originally Posted by sj22

Not true at all. Hundreds of people in this forum literally are running staggered and bmw sells them officially when you order a new car. You dont get a different car just because you ordered a staggered setup.

Here is the thing though - make you wheels are OEM spec, tires are new and star marked since the x drive is very picky on mismatched sizes. Doing that will mess up your differential (not transmission).

I have oem 21 wheels and oem star marked tires. Handles better than square actually.

Thanks. So the tires recommended by BMW's site? Did you stay with run-flats?

[AZTWW]

Yeah BMW's own 21 M wheels are staggered. I have been running staggered 22's for a year. As the other poster said, you want to make sure the rolling circumference is the same (or very close to less than like 1% difference) between the front and back.

If memory serves me, I have like 295 in the front with a 30 sidewall and 325 in the back with a 25 sidewall. When you put in the calculator, it is like 1.5% difference. Xdrive will hate you for anything over a few percent.

[sj22]

I did not stay with RFTs. Here are your two oem sizes:

1. (front) 285/40R20
(rear) 325/35R20
2. (front) 285/35R21
(rear) 325/30R21

Again, my advise, buy new tires and dont look for used ones.

BMW also sells this: https://www.shopbmwusa.com/PRODUCT/4...--COMPLETE-SET

[RED_Y_]

Your dealership person is not competent, staggered set up was offered by BMW with new vehicles as well as they are selling wheels and tires packages. Nothing to worry about as far as you get the right configuration with proper circumference. And I would ditch RFTs.

[pwrdbym]

You can use the tire size calculator at 1010tires to check the circumference of tire choices. But as others have said staggered from the factory on x drive is common. You can also get rid of RFTs if you so choose.

[gregdestep]

Maybe he was more concerned with offset (spacers) than the staggered set up? I can't remember now. And this may be a really dumb question (apologizing in advance) but what are star marked tires (as opposed to square)?

[pwrdbym]

Originally Posted by gregdestep

but what are star marked tires (as opposed to square)?

A star on the sidewall means that BMW worked specifically with the tire manufacturer to optimize ride, handling, and noise for the specific vehicle. For example you can buy a Bridgestone Potenza with or without the star and there will be some differences. Now, tracking down what those are specifically would be a chore and it will be different for every platform. For example the tire sidewall is thicker, or the tread is a slightly different shape, the tire may be .05in taller or shorter, etc... Using the star tire on your BMW is supposed to provide the most optimized driving performance per the engineers. You can however safely run any tire you like and the result will vary. It isn't likely you would damage the vehicle in any way. I suppose you could see some degradation in certain areas with different tires. People will debate all day on whether this is marketing BS or there is some benefit. One thing is for sure, you'll pay more for a "star" tire. I've switched from starred RFT's many times and found performance to be considerably better, especially in the ride category. Once my X5 RFTs wear out I will replace them with go-flats. My personal opinion is I've owned probably 15-20 BMWs and always bought tires based on price/performance and never given a second thought to star denotion. Buying a star tire is never a wrong answer, but it is likely an expensive one.

[sj22]

Originally Posted by pwrdbym

y personal opinion is I've owned probably 15-20 BMWs and always bought tires based on price/performance and never given a second thought to star denotion. Buying a star tire is never a wrong answer, but it is likely an expensive one.

My personal opinion is exactly opposite. Not arguing but I happened to get 2 non star marked tires for a staggered on my 7 series and that threw off the differential a few years ago. I guess once it happens, its changes how one thinks. The car was undrivable (had to put my winters back on) and it was never the same even after buying two star marked tires so I ended up selling it. Paying few hundred dollars more while buying vs. taking a few thousand dollar gamble with some of these newer complicated machines.

[bmwx5er]

Originally Posted by sj22

My personal opinion is exactly opposite. Not arguing but I happened to get 2 non star marked tires for a staggered on my 7 series and that threw off the differential a few years ago. I guess once it happens, its changes how one thinks. The car was undrivable (had to put my winters back on) and it was never the same even after buying two star marked tires so I ended up selling it. Paying few hundred dollars more while buying vs. taking a few thousand dollar gamble with some of these newer complicated machines.

Star marking is nothing special. Your dealer or whoever diagnosed your differential problem mislead you about the non-oem tires being the cause . Tires meeting oem specs are all fine, only depends on your comfort and $$$ you’re willing to shell.

[BDO]

Typical case of ignorant stealer staff talking nonsense.

[pwrdbym]

Originally Posted by sj22

My personal opinion is exactly opposite. Not arguing but I happened to get 2 non star marked tires for a staggered on my 7 series and that threw off the differential a few years ago. I guess once it happens, its changes how one thinks. The car was undrivable (had to put my winters back on) and it was never the same even after buying two star marked tires so I ended up selling it. Paying few hundred dollars more while buying vs. taking a few thousand dollar gamble with some of these newer complicated machines.

I find this really hard to believe. Service advisors (who are not techs) have come up with some really crazy stuff to explain why a vehicle is causing problems, and plenty of those excuses point to something the owner may have done rather than admitting fault to the manufacturer. I'd have to have an engineer explain to me how a non-star tire caused your problem because this engineer isn't buying it. BUT, like a said above, buying a starred tire isn't wrong.

[ianfp]

As others have said, stick preferably with OEM wheels and the correct tires will be specified for those wheels.

It is all to do with the rolling diameter of the tire. For example, 19 inch wheels will have the same overall diameter tires as 21 inch wheels - they will just have different sidewall depth to compensate.

[sj22]

Originally Posted by pwrdbym

I find this really hard to believe. Service advisors (who are not techs) have come up with some really crazy stuff to explain why a vehicle is causing problems, and plenty of those excuses point to something the owner may have done rather than admitting fault to the manufacturer. I'd have to have an engineer explain to me how a non-star tire caused your problem because this engineer isn't buying it. BUT, like a said above, buying a starred tire isn't wrong.

I used to not buy it too. Engineer here also I don't know how the differential can be so sensitive but I it happened to me. When this happened, it was with 2 of the toprated bmw indy shops in the city, not really something a dealer said. Infact, I never told anything to the dealer and quietly traded the car in afterwards. The car had 25k miles but was out of 4 yr warranty and I got a good deal since they never drove the car on a hill when it would usually act out.

So I don't think its all balonies. If you google stagged x drive and differential failure there are lots of people having issues. I personally think we underestimate the unequal wear on used tires and how it affects the diameter and thats when the issues pop up.

[kstinmb]

Originally Posted by sj22

I did not stay with RFTs. Here are your two oem sizes:

1. (front) 285/40R20
(rear) 325/35R20
2. (front) 285/35R21
(rear) 325/30R21

Again, my advise, buy new tires and dont look for used ones.

BMW also sells this: https://www.shopbmwusa.com/PRODUCT/4...--COMPLETE-SET

Interesting. My 2016 X5 40e has 275/40 and 315/35 on 20" from the factory. They look plenty big but I guess another half inch front and back won't hurt!

[bmwx5er]

Originally Posted by sj22

I used to not buy it too. Engineer here also I don't know how the differential can be so sensitive but I it happened to me. When this happened, it was with 2 of the toprated bmw indy shops in the city, not really something a dealer said. Infact, I never told anything to the dealer and quietly traded the car in afterwards. The car had 25k miles but was out of 4 yr warranty and I got a good deal since they never drove the car on a hill when it would usually act out.

So I don't think its all balonies. If you google stagged x drive and differential failure there are lots of people having issues. I personally think we underestimate the unequal wear on used tires and how it affects the diameter and thats when the issues pop up.

Differential/TC problems due to unevenly worn tires is a real thing, but that’s different from star or non-star tires as you were told during your diagnosis.You’ll cause damage to your TC if the difference in rolling diameters of the tires between each axle exceeds a tolerance (1% ??), even if they are BMW star rated.

[TOPEC]

u guys r making this all too complicated. as long as the tread depth difference is less than 2mm then ur ok. star designation or not, as long as all 4 have the star or not is ok, not a mix of 2 stars n 2 non star tires. if we look at our staggered oem tire sizes, the overall diameter works out to be exactly the same at 28.7".

Additionally for all-wheel drive vehicles:

The tyre size, manufacturer and tyre tread must be identical on all wheels; different tyre sizes between front and rear axles are only permissible if mixed tyres are fitted.
The tyre tread difference between tyres in all wheel positions must not exceed 2 mm (normal quality of the wheel control systems and wheel alignment requirement)

as for sj22's issue, its prob due to running 2 tires that were not star rated when the other 2 is. without knwoing exactly what tire brand/sizes he used, let's take for example, one of the more common tire that bmw used to use, the bridgestone RE050A RFT 225/40/18. bridgestone makes 3 versions of this tire size, bmw star spec, tpc spec (GM spec), n a 3rd generic rft version.

the overall diameter r as follows:
star spec = 25.2"
tpc spec = 25"
generic spec = not listed

so as u can see, even tho all 3 versions r marketed as the same size, the difference is 5mm. putting the tpc spec tire on while the opposite axle has tires that r 25.2" will automatically exceed the allowable tolerance of 2mm n cause the xdrive system to go out of whack.

[gregdestep]

What, if any, issues does adding rear spacers cause?

[ems328i]

Originally Posted by kstinmb

Interesting. My 2016 X5 40e has 275/40 and 315/35 on 20" from the factory. They look plenty big but I guess another half inch front and back won't hurt!

Those are indeed the factory sizes for 20", you can double check simply by looking at the drivers door sill (or in the owners manual) where the tire pressures are stated for each wheel size (up to 20"). 285/40R20 and 325/35R20 are not listed.

As others have mentioned, so long as the tire wear is even on all 4 wheels, and you stick to the correct sizes, you should have no issues with the X drive, although I would always recommend to buy new tires if at all possible.

I personally have 612 replicas from Italy (https://www.makwheels.it/en-ww/x-mod...m40izx.aspx#!/) and Goodyear Eagle F1 Asymmetric 3 SUV tires, and I love it...

[ems328i]

Originally Posted by gregdestep

What, if any, issues does adding rear spacers cause?

Adding rear spacers, providing you buy ones that are the correct fit, should give no issues at all.