[Robin93]

Hello - I would like to start by thanking everyone for creating such a great forum and wealth of knowledge. It has been an immensely helpful resource during my 2-Series ownership. Unfortunately, I think I may have gotten in over my head trying to change wheels and I’m hoping someone can offer some clarity and/or a solution.

I found a local deal on a set of BBS CH-R with tires and TPMS already installed - specs below. I scoured the forum and believed I had found the right size and that they would fit, but I went to a shop to have them installed and was promptly told they would interfere with the xDrive system because of the size difference and he wouldn't install them. Is there any chance this setup will work as-is or am I going tire shopping?

Car:
2016 BMW M235ix - Dinan lowering springs + a bunch of other non-suspension stuff
Currently on Style 436 Wheels: F 7.5x18ET45 R: 8x18ET52 , 225/40/18 tires all around

New Wheels BBS CH-R:
F: 19x8ET40 225/35/19
R: 19x9 ET44 255/35/19

Some of the threads referenced during research (not exhaustive):
https://www.2addicts.com/forums/showthread.php?t=956406
https://www.2addicts.com/forums/show....php?t=1802273
https://www.2addicts.com/forums/show....php?t=1603999 - exceptionally detailed thread with similar discussion points
https://www.2addicts.com/forums/show....php?t=1102721 - Specifically post 19 from VMR which has a representative example of a .7 variance in rolling diameter. When I apply the same calculations with the measurements on these CH-R’s, I’m seeing a variance of .88. In the post they recommend not exceeding a variance of 1.0, so I’m seemingly pushing that but not exceeding it.

Any guidance that can be offered is welcome. Thank you!

I attached a few pics of the car on current wheels for reference.

[Robin93]

I was able to get in touch with my regular wheel guy and ran up to his shop. We confirmed that the 19x9 ET44 255/35/19 will not fit in the rear. Fronts should be fine. Additionally, I noted an error in how I was calculating the variance shared above; I believe it would actually be a 3.6% variance in rolling diameter which would be way out of spec.

Ordered a new set of tires for the rear that will get in mid-week - Continental Extreme Contact Sports 255/30/19. This compound matches what came on the fronts. Perhaps down the line I’ll make the change to PS4S.

Hopefully everything will fit as expected. There is still some test fitting and checking that will be needed to make sure nothing rubs since the car is on the Dinan springs so we may still need to do spacers but that’s tbd. I’ll be sure to update back with pics and final installation specs to help out anyone who ends up trying to install these. Cheers!

[spidy512]

Howdy,

You wheel guy is correct. And you ordered the correct tire size. I have that exact wheel/tire combo and it works great.

FWIW, I am currently running 10mm spacers front and rear. No rub. But I am at stock height, and will more likely remove the spacers once I do lower the car.

Great looking car! I love the red...

Make sure to post pics once you get the wheels on!

josh

[Robin93]

I have to say this has turned into quite the endeavor but I’m happy to report the new wheels and tires are on and the first canyon run is in the books. Thanks Josh (spidy512) for all the information you’ve added to the forum - super helpful!

Long story short - new tires had to be shipped in from Cali which took a week + I was out on a vacation. Got it to the shop and the wheel lock key stripped. No dealer in Denver had a replacement/master key, so we had to wait for one to be shipped in. Then the dealer ultimately had the break the wheel locks to get them off since the replacement key stripped too - what a nightmare that was for everyone involved...

Finally got everything mounted yesterday - final specs below. Fitment is pretty much perfect with the Dinan lowering springs and no spacers. Had one minor rub on a bump at high speed in the canyon but otherwise no issues so far. Car goes in for plugs, rotors, and pads towards the end of the month and then it’ll be set for a while.

F: BBS CH-R 19x8ET40 225/35/19
R: BBS CH-R 19x9ET44 255/30/19
Conti Extreme Contact Sports all around

Cheers, Andrew

Enjoy some pics right after fitment and the first canyon run - Peak to Peak highway northwest of Denver.

[spidy512]

WOW!

Nice work! The red/black combo is spot on. Amd the lowering springs really finish the whole package. I cant wait for my B16's to get here....

Cheers!

[dradernh]

Originally Posted by Robin93

Enjoy some pics right after fitment and the first canyon run - Peak to Peak highway northwest of Denver.

Thanks for sharing, esp. your last photo!

<going OT>

I was born in the Mile High City. We moved away when I was two, and I returned most summers to stay with my grandparents on Wash Park. After the old man retired to Boulder in the early 70s, I spent a few weeks traveling around the region with him every year through the mid-80s. Your photo reminded me that I miss driving the nearby mountain roads like the Peak to Peak Highway. BMWs were made for Colorado's mountain roads – and vice-versa.

The map below shows a month-long RV road trip we took in '96. The asterisks, if they can be made out, are where we overnighted. The purpose of the trip was to view the widest range of Colorado landforms and for the old man to show me where he'd spent time in the '20s-'40s. As is true for all of our states, CO is a truly spectacular one. Someone with time on their hands and who wishes to closely examine a concentrated part of the American West could do worse than to follow the route he chose.



<end OT>

[Robin93]

Wow - that is an incredible trip and memory to have. I've been fortunate enough to live in Colorado Springs, Fort Collins, and now Denver for nearly all of my life. Colorado is truly exceptional!

[TrboMike]

Wait, there are MAPS on PAPER?

[KennyFSU]

Wheels look great, fitment is on point.