[IronFather]

Around midyear, I expect to put some new shoes on my M850i coupe and figure that would be a good time to replace the factory wheels. I would definitely want to go wider all the way around but keep the overall diameter the same as to not cause the speedo to be off. If anyone has any suggestions for wheel manufacturers, sizes, and what won't work, please enlighten me. Thanks!

[10TrillionUSDT]

Originally Posted by IronFather

Around midyear, I expect to put some new shoes on my M850i coupe and figure that would be a good time to replace the factory wheels. I would definitely want to go wider all the way around but keep the overall diameter the same as to not cause the speedo to be off. If anyone has any suggestions for wheel manufacturers, sizes, and what won't work, please enlighten me. Thanks!

I am looking to get something like this on my M8

https://www.lamborghini-talk.com/thr...itment.231462/

[AndyVTForged]

VTForged RST-20 Track Spec 21x10/12 on our customers M8 Coupe

[IronFather]

Originally Posted by AndyVTForged

VTForged RST-20 Track Spec 21x10/12 on our customers M8 Coupe

Those are beautiful wheels. One of my main questions would be what could I get away with on width. I've heard 10.5 on the rear which I would guess a 305 size tire would be max on that size rim.

[Moopai]

You got beautiful wheels with deep concave... I wish my M850GC have those wheels! I would just get 12mm spacers all around and you will get the aggressive look!

My two cents!

Originally Posted by IronFather

Around midyear, I expect to put some new shoes on my M850i coupe and figure that would be a good time to replace the factory wheels. I would definitely want to go wider all the way around but keep the overall diameter the same as to not cause the speedo to be off. If anyone has any suggestions for wheel manufacturers, sizes, and what won't work, please enlighten me. Thanks!

[IronFather]

Originally Posted by Moopai

You got beautiful wheels with deep concave... I wish my M850GC have those wheels! I would just get 12mm spacers all around and you will get the aggressive look!

My two cents!

Thank you for the compliment and the.02😁. I'm currently running spacers all the way around but would prefer having the wider stance without the spacers. 275 on the rear to me is just too skinny. I know having AWD negates some of need for thick rubber in the rear, but a 275 is just too thin for car as wide as the 850 in my opinion.

[snowbimmer]

Originally Posted by IronFather

Thank you for the compliment and the.02��. I'm currently running spacers all the way around but would prefer having the wider stance without the spacers. 275 on the rear to me is just too skinny. I know having AWD negates some of need for thick rubber in the rear, but a 275 is just too thin for car as wide as the 850 in my opinion.

You're thinking like I did. M850 tires and wheels are too small. After researching other forum members, I jumped up to a 9" front with a 255/35 and a 10.5" rear with a 285/30. But the M850 tire profile is one down from the M8 and the rears looked way stretched. So I went to a 295. Looks great. I think some members are running the 305.

Be careful to distinguish what an M8 owner says about their wheels. M8 offsets are completely different. M8 OEM offsets are 28 front and back. An OEM M8 wheel doesn't play well on an M850 - I've tried. Way too much poke. A custom wheel on an M8 may still not fit on an M850 if they don't have the right offset, although some wheels can be fully customizable where you can pick your own offset.

Our OEM offsets are 26 front and 41 rear. My Vossen HF5s have a 32 front offset that pushes the wheel out 7mm. Could probably have gone with their 25 offset for an additional 7mm, but I think it works as it is. The rears are a 45 offset and the wheels were pushed out 15mm. Just right, I think. With a 45 offset and an inch and a half wider wheel, the rim was pushed 23mm closer to the strut - so there seems to be plenty of room to screw around with back there.

Handling is right in there now. It's very confident and planted at high speeds. It still doesn't handle as well as my 2 F90s did, and obviously the M8, but it's a helluva lot closer now. Physics still rules when driving a 4800 lb boat rocket. Here's a couple pics:

[mikerx5]

Thats sits SOOOO nice

[IronFather]

Originally Posted by snowbimmer

You're thinking like I did. M850 tires and wheels are too small. After researching other forum members, I jumped up to a 9" front with a 255/35 and a 10.5" rear with a 285/30. But the M850 tire profile is one down from the M8 and the rears looked way stretched. So I went to a 295. Looks great. I think some members are running the 305.

Be careful to distinguish what an M8 owner says about their wheels. M8 offsets are completely different. M8 OEM offsets are 28 front and back. An OEM M8 wheel doesn't play well on an M850 - I've tried. Way too much poke. A custom wheel on an M8 may still not fit on an M850 if they don't have the right offset, although some wheels can be fully customizable where you can pick your own offset.

Our OEM offsets are 26 front and 41 rear. My Vossen HF5s have a 32 front offset that pushes the wheel out 7mm. Could probably have gone with their 25 offset for an additional 7mm, but I think it works as it is. The rears are a 45 offset and the wheels were pushed out 15mm. Just right, I think. With a 45 offset and an inch and a half wider wheel pushed the rim 23mm closer to the strut - so there seems to be plenty of room to screw around with back there.

Handling is right in there now. It's very confident and planted at high speeds. It still doesn't handle as well as my 2 F90s did, and obviously the M8, but it's a helluva lot closer now. Physics still rules when driving a 4800 lb boat rocket. Here's a couple pics:
Attachment 3361546Attachment 3361547

Thank you very much for the info. I will arm myself with the data you provided when I start to shop. I love the look of the Vossens on your 850. Beautiful ride!

[Moopai]

What size of spacers are you running now?

This coming summer I'm replacing the crappy Bridgestones with Michelin PS4s or P5s if available and I'm seriously considering to go with 285/30R20 on the rear on the M728 that I currently have as long as the tire does not extend outside the walls of the rear panel as I'm running 12mm spacers front and back. The current setup with 245 front 275 rear is giving me an almost flushed look but could extend a little more. I agree the M850 is a wide car and needs a wider rears than 275/30 but I'm sure BMW has a reason on why they use these sizes...

Curious to see what set up you will end up with :-) Good Luck!

Originally Posted by IronFather

Thank you for the compliment and the.02😁. I'm currently running spacers all the way around but would prefer having the wider stance without the spacers. 275 on the rear to me is just too skinny. I know having AWD negates some of need for thick rubber in the rear, but a 275 is just too thin for car as wide as the 850 in my opinion.

[IronFather]

Originally Posted by Moopai

What size of spacers are you running now?

This coming summer I'm replacing the crappy Bridgestones with Michelin PS4s or P5s if available and I'm seriously considering to go with 285/30R20 on the rear on the M728 that I currently have as long as the tire does not extend outside the walls of the rear panel as I'm running 12mm spacers front and back. The current setup with 245 front 275 rear is giving me an almost flushed look but could extend a little more. I agree the M850 is a wide car and needs a wider rears than 275/30 but I'm sure BMW has a reason on why they use these sizes...

Curious to see what set up you will end up with :-) Good Luck!

I'm running 12 up front and 18 on the rear. Car looks good but I can't stand looking at a skinny tire from the rear. I'm probably the only one who notices it, or thinks it's a issue. At least that's what my wife says lol.

[snowbimmer]

Originally Posted by IronFather

I can't stand looking at a skinny tire from the rear. I'm probably the only one who notices it, or thinks it's a issue. At least that's what my wife says lol.

You are not sick. And you are not alone. We're here for ya. 🤣🤣🤣

[dubbrand]

I've found the speedo to be off from the factory, on both my M850i and my wife's X7. Both are over by 2mph. There's three radar signs near my house and all show it over by 2. OEM wheels and my aftermarket 21s give same results. Drove a rental audi by them and mph matched. My 21s are 21x9.5 et26 front. 21x11 et36 rear. Sit flush once lowered on KW HAS. At factory height they poke out. Can post pics later from my desktop. Mobile gives me issues here.

[IronFather]

Originally Posted by dubbrand

I've found the speedo to be off from the factory, on both my M850i and my wife's X7. Both are over by 2mph. There's three radar signs near my house and all show it over by 2. OEM wheels and my aftermarket 21s give same results. Drove a rental audi by them and mph matched. My 21s are 21x9.5 et26 front. 21x11 et36 rear. Sit flush once lowered on KW HAS. At factory height they poke out. Can post pics later from my desktop. Mobile gives me issues here.

Good info. Would love to see the pics. Thank you.

[dubbrand]

Originally Posted by IronFather

Good info. Would love to see the pics. Thank you.

Here's a small gallery. Can send you more if you need

https://photos.app.goo.gl/mYeiUv1RoU3cdEGf9

[IronFather]

Originally Posted by dubbrand

Here's a small gallery. Can send you more if you need

https://photos.app.goo.gl/mYeiUv1RoU3cdEGf9

Link is not working.

[dubbrand]

Originally Posted by IronFather

Link is not working.

Try this

https://photos.app.goo.gl/yeEepthzLQ8guzyj9

[IronFather]

Originally Posted by dubbrand

Try this

https://photos.app.goo.gl/yeEepthzLQ8guzyj9

I'll try it on my pc when I get home. The only option I see is a copy and paste on my phone.

[dubbrand]

They both work for me so I dunno. If you just check out my old posts thru my profile you can see pics too

[IronFather]

Originally Posted by dubbrand

They both work for me so I dunno. If you just check out my old posts thru my profile you can see pics too

I finally got to take a look at your car pictures. Wow! What a slick ride. I really like those wheels. What brand/model are they? Thanks.