[RigRag93]

Just a little back story, I work with an aftermarket wheel company and they are in the process of developing/releasing a new wheel for the G42 platform. The team picked up a sick Brooklyn Gray spec and we went to work right away. For reference the brand is Curva Concepts and with this new young team, they are looking to completely restructure the brand.

Anyways, to the good stuff. I don't want to spoil the fun yet with offsets and whatnot, but I think if you're looking for 18"/19" track set ups, you can go pretty beefy. You can also run a 20" comfortably for those looking to go larger with the wheels. Based on some different options, we think we can squeeze a 10" wheel in the rear with sufficient clearance for beefy tires.

[SN1P3]

Thanks for sharing! Looking forward to what they come up with!

[joeyg4282]

Subbing in on this thread...am interested to see what options you come up with....

[PR X13.5i]

Originally Posted by RigRag93

Just a little back story, I work with an aftermarket wheel company and they are in the process of developing/releasing a new wheel for the G42 platform. The team picked up a sick Brooklyn Gray spec and we went to work right away. For reference the brand is Curva Concepts and with this new young team, they are looking to completely restructure the brand.

Anyways, to the good stuff. I don't want to spoil the fun yet with offsets and whatnot, but I think if you're looking for 18"/19" track set ups, you can go pretty beefy. You can also run a 20" comfortably for those looking to go larger with the wheels. Based on some different options, we think we can squeeze a 10" wheel in the rear with sufficient clearance for beefy tires.

Some beefy tire on 18"x10" wheels.

[JDM_240]

Im hoping to run 19x9 in the front and 19x10 in the rear. TE37s. Please please please keep us posted on all of your findings!

[conradb58]

Originally Posted by JDM_240

Im hoping to run 19x9 in the front and 19x10 in the rear. TE37s. Please please please keep us posted on all of your findings!

I believe the fitments for this car will surprise everyone. This car and the M2C have near identical track widths front & rear 🙂

[RigRag93]

I will keep you all posted and share photos once the wheels are on. Hopefully mid-Jan.

[sirantsE90]

SUBd. Ours should hit the port in 3 weeks. We will need a set asap!

[SWOHammer]

Originally Posted by sirantsE90

SUBd. Ours should hit the port in 3 weeks. We will need a set asap!

As a retired US Naval Officer, let me assure you…we don't want the ship to "hit" anything or you're looking at a lot longer wait…

[RigRag93]

Originally Posted by SWOHammer

As a retired US Naval Officer, let me assure you…we don't want the ship to "hit" anything or you're looking at a lot longer wait…

Good call haha! Update now says mid-Feb

[XC3LLR8]

Originally Posted by SWOHammer

As a retired US Naval Officer, let me assure you…we don't want the ship to "hit" anything or you're looking at a lot longer wait…

Must drive you crazy with your status set on "Private", which is one up from "Enlisted".

[Jack@AUTOID]

Originally Posted by JDM_240

Im hoping to run 19x9 in the front and 19x10 in the rear. TE37s. Please please please keep us posted on all of your findings!

Any idea on offsets at the moment?

I am confirming my 19x9 and 19x10s too.

[DaveDee]

Originally Posted by Jack@AUTOID

Any idea on offsets at the moment?

I am confirming my 19x9 and 19x10s too.

Just got mine a few days ago and had done some research finding this for the offsets....https://www.alloywheelsdirect.net/bm...93m_wheel_7830
These guys claim they are genuine wheels and have the BMW G42 M240i X-Drive series specs on their site and they make sense
But I spent a few hours at our local wheel manufacturer who is huge here in Australia (Koya Wheels) and I'm looking at some forged wheels
Tyre sizes 245/35/19 and 285/30/19. This keeps the diameter within the required 1% of the X-Drive spec and works out to .4% (same as the stock 225/40s and 255/35s
I'll get all the figures soon but one of the factors was brake clearances not so much on the width of the callipers but they are very tall and come close to the barrels. The fully forged wheel is a good way around this to give adequate diameter on the inner barrel
These will be a very tight fitment and when done I'll post the specs and pics
All the other usual stuff getting done this week

[CTGT2005]

Same here! Would love to see someone stuff a 295/30/19 on a 10" wheel in back and a 265/35/19 on 9" up front. Keep us posted guys!

[DaveDee]

Originally Posted by CTGT2005

Same here! Would love to see someone stuff a 295/30/19 on a 10" wheel in back and a 265/35/19 on 9" up front. Keep us posted guys!

After spending a stupid amount of time researching this a good calculator:
https://tiresize.com/comparison/

The 265/295 comparison is a tad out (1.1%) difference in diameter for X- Drive requirements but 295/30. /255/35 is the identical diameter and perfect for X drive require specs but the fitment of 295s on the back was too ambitious according to the guys who did all the measurements.
285/30 and 245/35 is the best all around match with a tight fitment on a 10" and 8.5" wheel. I'm guessing this won't look to shabby

[CTGT2005]

Probably a better choice, but smaller than factory. I would hate to give away miles to smaller tires. My speedometer already reads about 3mph faster than GPS.

[XC3LLR8]

Originally Posted by DaveDee

Just got mine a few days ago and had done some research finding this for the offsets....https://www.alloywheelsdirect.net/bm...93m_wheel_7830
These guys claim they are genuine wheels and have the BMW G42 M240i X-Drive series specs on their site and they make sense
But I spent a few hours at our local wheel manufacturer who is huge here in Australia (Koya Wheels) and I'm looking at some forged wheels
Tyre sizes 245/35/19 and 285/30/19. This keeps the diameter within the required 1% of the X-Drive spec and works out to .4% (same as the stock 225/40s and 255/35s
I'll get all the figures soon but one of the factors was brake clearances not so much on the width of the callipers but they are very tall and come close to the barrels. The fully forged wheel is a good way around this to give adequate diameter on the inner barrel
These will be a very tight fitment and when done I'll post the specs and pics
All the other usual stuff getting done this week

I'm confused on this 1% math. You're saying the diameter difference between 245/35 and 285/30 is .4%, but it's actually 0.99 which is approximately 1:1. Virtually no difference, but you end up with a front tire slightly taller than your rear tire. Or did you mean 245/35 and 285/35?

If you meant the latter, then the diameter difference is 4%, not .4%.

Regarding the OEM 225/35 and 255/35, the diameter difference is 3.2%. Does this 1% variance mean any change needs to not exceed 3.2% by 1 percentage point, so anywhere between 2.2% to 4.2% between front and rear is acceptable?

If the above is true, then a 245/35 front and a 285/35 rear is about as large of a delta as you can go w/o exceeding 1 percentage point of 3.2%.

Someone please check my math and correct me if I'm not getting this.

[240idax]

Originally Posted by XC3LLR8

I'm confused on this 1% math. You're saying the diameter difference between 245/35 and 285/30 is .4%, but it's actually 0.99 which is approximately 1:1. Virtually no difference, but you end up with a front tire slightly taller than your rear tire. Or did you mean 245/35 and 285/35?

If you meant the latter, then the diameter difference is 4%, not .4%.

Regarding the OEM 225/35 and 255/35, the diameter difference is 3.2%. Does this 1% variance mean any change needs to not exceed 3.2% by 1 percentage point, so anywhere between 2.2% to 4.2% between front and rear is acceptable?

If the above is true, then a 245/35 front and a 285/35 rear is about as large of a delta as you can go w/o exceeding 1 percentage point of 3.2%.

Someone please check my math and correct me if I'm not getting this.

The issue with your math is that the OEM tires are 225/40 and 255/35. Not 225/35. The difference in OEM tires is .4%

[DaveDee]

Originally Posted by XC3LLR8

I'm confused on this 1% math. You're saying the diameter difference between 245/35 and 285/30 is .4%, but it's actually 0.99 which is approximately 1:1. Virtually no difference, but you end up with a front tire slightly taller than your rear tire. Or did you mean 245/35 and 285/35?

If you meant the latter, then the diameter difference is 4%, not .4%.

Regarding the OEM 225/35 and 255/35, the diameter difference is 3.2%. Does this 1% variance mean any change needs to not exceed 3.2% by 1 percentage point, so anywhere between 2.2% to 4.2% between front and rear is acceptable?

If the above is true, then a 245/35 front and a 285/35 rear is about as large of a delta as you can go w/o exceeding 1 percentage point of 3.2%.

Someone please check my math and correct me if I'm not getting this.

The 1% referred to is the max allowed difference between the rear wheel and front wheel rolling diameter.

Agreed OE options are 225/40 front 255/35 rear or optional 245/35/19 wheels front 255/35/19 rear.

I used an online calculator to get the max tyre diameters that could be used with X Drive limitations and had less that a 1% rolling diameter difference between front and rear wheels

Largest usable combination that would fit the car were 285/30/19 rear and 245/35/19 front

Attached is a screenshot of the calculator result showing .4% difference between front wheels and rear wheels, also for reference the same calculator results for the OE 255/35 rear 225/40 front

[XC3LLR8]

Originally Posted by 240idax

The issue with your math is that the OEM tires are 225/40 and 255/35. Not 225/35. The difference in OEM tires is .4%

My bad, didn't realize the 225 was a 40 ratio. I ordered the ZTK package which has a 245/35 and 255/35. The delta there is 1.1%, so I guess that's BMW approved.

[XC3LLR8]

Originally Posted by DaveDee

The 1% referred to is the max allowed difference between the rear wheel and front wheel rolling diameter.

Agreed OE options are 225/40 front 255/35 rear or optional 245/35/19 wheels front 255/35/19 rear.

I used an online calculator to get the max tyre diameters that could be used with X Drive limitations and had less that a 1% rolling diameter difference between front and rear wheels

Largest usable combination that would fit the car were 285/30/19 rear and 245/35/19 front

Attached is a screenshot of the calculator result showing .4% difference between front wheels and rear wheels, also for reference the same calculator results for the OE 255/35 rear 225/40 front

Thanks for the clarification.

Looks like the website I was using has a 1mm difference in diameter compared to the website you're using, but should be close enough that the transmission won't know the difference.

According to Tire Rack, and in regards to the ZTK package, an 8.5" wheel can handle a 255, while a 9.5" wheel can handle a 285. This means a 255/40 front and a 285/35 rear will give you a -0.4% difference, which should be a nice meaty look if that's your thing (which it is for me).

*Ignore the wheel width's and offset's in the screen shots below. I was only interested in tire width and diameter.

[XC3LLR8]

Originally Posted by XC3LLR8

My bad, didn't realize the 225 was a 40 ratio. I ordered the ZTK package which has a 245/35 and 255/35. The delta there is 1.1%, so I guess that's BMW approved.

Given the fact BMW seems to approve a 1.1% delta with the ZTK package, I'll go out on a limb and say we may get away with a 1.2% delta as well. If so, and not wanting to go as meaty as what I mentioned above, here's a setup that may look nice on the OEM wheels...

Size 1 and Size 2 below can serve two purposes: 1) It can show the difference between the OEM size and the new wider size on the rear of the ZTK (graphically and data), or 2) It can show the differences with a new front/back setup on the ZTK (graphically).