[XC3LLR8]

Originally Posted by G42.Drxw

Appreciate it! I wouldn’t have no issues lowering the car or needing to run spacers ?

You're on your own there, since I'm on stock suspension and plan to keep it that way. Sorry, can't provide a recommendation if lowered.

If wheels are perfectly flush with fender when on stock suspension, what are they when lowered? Do they stick out more? If so, I'd stick with et25 instead of et20 and apply a little negative camber.

[G42.Drxw]

Originally Posted by XC3LLR8

You're on your own there, since I'm on stock suspension and plan to keep it that way. Sorry, can't provide a recommendation if lowered.

If wheels are perfectly flush with fender when on stock suspension, what are they when lowered? Do they stick out more? If so, I'd stick with et25 instead of et20 and apply a little negative camber.

Got it! Again thanks for the help !!

[KJ10]

Finally have the new set on!

[Fidiman]

Originally Posted by KJ10

Finally have the new set on!

Are these the OEM 826M wheels?

[KJ10]

Originally Posted by Fidiman

Are these the OEM 826M wheels?

They are not. They are definitely the same look but these were a set I custom ordered through a forum member.

[VegasG42]

Originally Posted by KJ10

They are not. They are definitely the same look but these were a set I custom ordered through a forum member.

Rear wheels outside the fender ?

[KJ10]

Originally Posted by VegasG42

Rear wheels outside the fender ?

They are almost completely flush looking straight down. The way the fender is shaped makes them look a lot wider from the front and back.

[nype]

Still researching and learning about this platform. I've got a 2023 M240i with the ZTK package.

With respect to different tire makes/models, never mind even different sizes etc.. I was talking with one of the head techs at a local BMW dealership, and he had these comments.

Sounds overly cautious, no?

Only use OEM BMW star rated tires or you will destroy the transfer case and it won't be covered by warranty

Even the exact brand tire and size but not star rated will mess it up. The star rated ones have matching rolling diameters.

Star rated tires are reinforced in areas to prevent excessive wear and they all have the exact same rolling diameters in sets per xDrive spec.

[BG42]

Originally Posted by nype

Still researching and learning about this platform. I've got a 2023 M240i with the ZTK package.

With respect to different tire makes/models, never mind even different sizes etc.. I was talking with one of the head techs at a local BMW dealership, and he had these comments.

Sounds overly cautious, no?

Only use OEM BMW star rated tires or you will destroy the transfer case and it won't be covered by warranty

Even the exact brand tire and size but not star rated will mess it up. The star rated ones have matching rolling diameters.

Star rated tires are reinforced in areas to prevent excessive wear and they all have the exact same rolling diameters in sets per xDrive spec.

First mistake was talking to the tech 2nd posting it haha.

[LoveSickRemix]

Originally Posted by nype

Still researching and learning about this platform. I've got a 2023 M240i with the ZTK package.

With respect to different tire makes/models, never mind even different sizes etc.. I was talking with one of the head techs at a local BMW dealership, and he had these comments.

Sounds overly cautious, no?

Only use OEM BMW star rated tires or you will destroy the transfer case and it won't be covered by warranty

Even the exact brand tire and size but not star rated will mess it up. The star rated ones have matching rolling diameters.

Star rated tires are reinforced in areas to prevent excessive wear and they all have the exact same rolling diameters in sets per xDrive spec.

I looked into it, and the only thing i seen about destroying transfer cases is the wheel diameter difference between front and rear. But even that has some push back as a reason not to honor the warranty. The tire thing does sound like a lie honestly, but the wheel size sounds like it effects older bimmers more than modern ones. Worth looking into tho.

[VegasG42]

So, has anyone actually measured their xDrive BMW Star rated tires - Front vs. Rear , to see if the circumference is identical ?

Or are they a bit off from factory ?

Researching now to try and find more info. But I thought the consensus was that anything below 1% circumference difference was acceptable . Is that coming from BMW ?

[Pentland]

You’ll find this of interest

https://f30.bimmerpost.com/forums/sh...5&postcount=37

[Maxp]

Can anyone give me any pointers as to whether or not these wheels will fit my m240i xdrive? It is coming with the staggered performance non run flat tires staggered 791m wheels. The offsets are larger so would I need spacers?
https://www.ebay.com/itm/19593264325...utFitment=true

[Wasp_Factory]

Compared to the ZTK wheels, the fronts would be 10mm further inboard and the rears would be 13.5mm further inboard. I'd suggest you'd want 10 or 12mm spacers up front and 15mm at the rear - perhaps 10 and 12mm if you don't have the fender flares.

[Wasp_Factory]

PS - I think they'd look awesome. Make sure you check the delta between front and rear rolling radius and ensure it is <1% if you have Xdrive

[Pentland]

Originally Posted by Wasp_Factory

PS - I think they'd look awesome. Make sure you check the delta between front and rear rolling radius and ensure it is <1% if you have Xdrive

This 1% front to rear “fact” is appearing on several threads of late.
Can anyone quoting it please substantiate it?

[Wasp_Factory]

It certainly isn't stated in the G42 M240iX user manual and perhaps it is folk lore become unofficial fact, but there are multiple pages in this forum that state it as a requirement.

For me, I have aftermarket wheels and wasn't prepared to take the risk that I had a clutch transfer case issue which wasn't covered by warranty, so I stuck with the OEM tyre sizes. I'd add that all Xdrives from factory come with front/rear with <1% rolling radius delta and also star marked (ie BMW homologated tyres) actually have rolling radii that differ from non star marked to ensure the <1% delta. With all of that, I'm certainly not brave enough to buck the trend.

[Wasp_Factory]

A quick Google yielded an old document on Xdrive with DSC8:

Tire Tolerance Logic
The tire tolerance logic detects different tread circumferences on the front and rear axles.
This occurs when:
• Mixed tires are used
• Space saving spare tire is installed
• Tires are used that have been worn down to different levels
Normally, tire circumference deviations result in drivetrain torque bias (unwanted variations).
The tire circumference can fluctuate up to 1% or more as a result of mixed tires or wear.
The tire tolerance logic decides depending on the driver's command and driving situation
whether the slip is to occur in the transfer case clutch or at the contact area between tire
and road.
If the slip is permitted in the transfer case clutch, the locking pressure set by the pre-control is reduced in order to keep the work loss low. In the driving dynamic control situation,
the clutch is locked slightly more than normal, the four wheel drive is always guaranteed
when required.
For maximum xDrive performance, tires (and wheels) of the same diameter should be installed on the vehicle.

[Pentland]

Originally Posted by Wasp_Factory

It certainly isn't stated in the G42 M240iX user manual and perhaps it is folk lore become unofficial fact, but there are multiple pages in this forum that state it as a requirement.

.

Agree. There are multiple pages / websites on the internet that claim the world is flat - doesn’t make it so.

[blue135]

Get two tires whose overall diameter differs by 2% or more but are close in diameter to what you are running on your 240 X-drive. Make a visible mark on each tire. Now, roll each tire one or two full revolutions. Measure the difference in distance covered.
Keep in mind that your front and rear tires are mechanically connected (unlike rod). How does the car’s drive system compensate for the difference covered between the front & rear as you go down the road at 40 mph or 90 mph?
BMW says the system will compensate for a 1% difference.
Whether that is of consequence to you, it is to BMW. Just like a tune, you can decide which path to follow.

[Pentland]

Originally Posted by blue135

BMW says the system will compensate for a 1% difference.
Whether that is of consequence to you, it is to BMW. Just like a tune, you can decide which path to follow.

Do they though? People keep saying this but not backing up.

[nype]

Originally Posted by Pentland

Do they though? People keep saying this but not backing up.

I'd also like to know where all of this is written so that owners are clear on warranty voiding situations that they may be entering in to.