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I have a 1985 635csi and I am looking at 18" wheels, 8 inches wide front and 9 inches wide rear. 120x5 with 35mm offset.
My current wheels are 16" diameter x 7 inches wide with 20mm offset Style 5 BMW wheels.

Any advice as to whether the 18" I am looking at? What if anything do I do so they will fit?

Thanks.

Try the website ‘willtheyfit.com’

Hi,

https://www.willtheyfit.com/ is cool, however i use https://www.wheel-size.com because of detailed options and visual explanation.

One of my an earlier fitment calculations is over here: https://www.wheel-size.com/calc/?wheel1 ... 0mm&sr=0mm, just replace the numbers for your parameters.

/Peter

35mm off set will be close you will probably need a 20mm spacer in the front so they don't rub inside on the strut tube.


18" are a little big for these cars in my opinion. It will ruin the geometry, But people do it.

Read , Read, Read there are quite a few posts in this forum on guys using 18" wheels.

My M6 came to me with 18's. to make things work well, I made custom roll center adapters for the front, made custom spherical bushings, and welded in adjusters to the rear control arms.

Even with all the mods., I can only run 225/35-18 tires up front or things rub. The front tire is too thin to my eyes, but in the rear, I was able to get 275/45-18's spooned on. The thicker sidewall really is the key to make the wheel/tire combo. look right for the body.

I agree that 17's are really the biggest wheel that still looks "right" on a 6er.

Jose

I have 17 inch Style 32's on my E24, the 17 inch fit perfectly in my opinion.

When mated with correct size tires, the 18" wheel look just as proper as 17". It depends on the stance of the suspension and the type of wheel.

Here is my 87 m6 with 17's and H&R lowering springs. I really like the setup, after I learned the wheels needed a hubcentric ring because they were from an e39 and the hub is slightly larger.

I think 18 just passes the threshold of too modern for this body style.

16 or 17 is just right IMO. With Vogtland lowered springs.

16 17

To my eyes, 17" is the ideal wheel size for an E24; mine are RS 198s (17 X 8.5, ET13) with 245/40 tires. Next time tires are due, I think I'll switch to a slightly less aggressive, more "typical" upgrade size of 235/45. I'd like a slightly larger sidewall for a better ride and to reduce suspension wear.

However, I also own an E28 and I feel that with the taller/narrower sedan body 17s appear a little bit too large. For that car I'm using E28 M5 wheels (16 X 7.5, ET20) and they're about the perfect fit.

Perfect fit, looks great Larry.

LarryM wrote: ↑Sun Apr 18, 2021 7:05 am To my eyes, 17" is the ideal wheel size for an E24; mine are RS 198s (17 X 8.5, ET13) with 245/40 tires. Next time tires are due, I think I'll switch to a slightly less aggressive, more "typical" upgrade size of 235/45. I'd like a slightly larger sidewall for a better ride and to reduce suspension wear.

However, I also own an E28 and I feel that with the taller/narrower sedan body 17s appear a little bit too large. For that car I'm using E28 M5 wheels (16 X 7.5, ET20) and they're about the perfect fit.

It looks great; proportions are just right.

Do you ever have any issues with front tires rubbing the fender? Currently seeking front tires for my 16x8.5 wheels, et11. Fender rub is my biggest stress point.

L.Tigre wrote: ↑Tue Sep 13, 2022 5:42 pm

LarryM wrote: ↑Sun Apr 18, 2021 7:05 am To my eyes, 17" is the ideal wheel size for an E24; mine are RS 198s (17 X 8.5, ET13) with 245/40 tires. Next time tires are due, I think I'll switch to a slightly less aggressive, more "typical" upgrade size of 235/45. I'd like a slightly larger sidewall for a better ride and to reduce suspension wear.

However, I also own an E28 and I feel that with the taller/narrower sedan body 17s appear a little bit too large. For that car I'm using E28 M5 wheels (16 X 7.5, ET20) and they're about the perfect fit.

It looks great; proportions are just right.

Do you ever have any issues with front tires rubbing the fender? Currently seeking front tires for my 16x8.5 wheels, et11. Fender rub is my biggest stress point.

My car is lowered on Eibach springs, about 1 1/2". With 17" X 8.5" ET13 wheels and 245/40-17 tires I've never had any interference with the fenders but the tires are VERY close to the struts. (Next time I'm due for tires I'll be switching to 235/45s not just for the extra bit of clearance but also for a little extra sidewall.)

My set up is similar. E39 style 5s with H&R springs. I have run 225-45/17 since I got the wheels. The front spring perches stay polished where the tire juuuust contacts on occasion. Often enough not to rust, but not enough to show on the tire. I don't recall the wheel's offset right now. No fender rub with the various tires I've run over the years.

If you're wanting a good standard:

Diameter: 15, 16 or 17 inch rim
Width: 8, up to 10 rear
Offset: ET23 or down to ET15
Stud pattern: 5x 120

The rears have plenty of space and can take an 8", 9" or even a 10" rim with the proper offset and tires up to 255 or 265.
The fronts are more critical and 8" is generally the largest without a spacer or a small ET.

A typical replacement wheel & tyre combo is:

16" x 7" or 7.5" @ ET20 or less with a 225/50-16 tyre that has a rolling diameter of 24.85" (631.2mm)
/OR/
17" x 7.5" or 8" @ ET20 or less with a 235/45-17 tyre that has a rolling diameter of 25.32" (643mm)

Acceptable rolling diameters range from 24.8" to 25.4" (632mm to 645mm), without needing a speedo adjustment.

Factory rolling diameters:
TRX 390 = 24.88" (632mm)
TRX 415 = 24.84" (631mm)
14" x 6" = 25.30" (642mm)

Staggered vs Straight

Straight set:
235/45-17 all round = 25.3" (643mm) rolling diameter.

Staggered:
Fronts: 225/45-17 (25") (635mm)
Rears: 255/40-17 (25") (635mm)

The thing that dissuades me from running a staggered set is the tyre wear. The E24 typically wears the fronts on (both) the shoulders and the rears more in the middle of the tread.
The chassis is designed to have the tyres periodically rotated front to rear to even out the tyre wear.
With a staggered set you can't do that, and the result is that you might get as little as 1/3 life out of a set of tyres vs a square set.

TimU - This is a great summary and I've used it before in doing some basic planning/sizing.

One added complexity for those of us with 16" diameter wheels is there's virtually no availability of 235 width tires. The right 235r17 I can find all day long. And similar 225r16 has plenty of availability. But 2235r16 is quite rare unfortunately.

It's been made harder by the 8.5" wheel. Mating a 225 wheel to an 8.5" rim is technically a 'stretch' situation when you go by the tire installer guidelines. A few declined to do it. (I think it was a kind of liability / by-the-rules standpoint, more than any real risk). But I have an installer who said "just bring it all in and we'll make it work." So the tires are on their way, Continental 225/55r16s to match with ACT mesh wheels.

BTW these are the rims, see pic. I am like a kid before Christmas waiting to get them installed. Mid-next-week...

L.Tigre wrote: ↑Fri Sep 23, 2022 7:29 pm TimU - This is a great summary and I've used it before in doing some basic planning/sizing.

One added complexity for those of us with 16" diameter wheels is there's virtually no availability of 235 width tires. The right 235r17 I can find all day long. And similar 225r16 has plenty of availability. But 2235r16 is quite rare unfortunately.

It's been made harder by the 8.5" wheel. Mating a 225 wheel to an 8.5" rim is technically a 'stretch' situation when you go by the tire installer guidelines. A few declined to do it. (I think it was a kind of liability / by-the-rules standpoint, more than any real risk). But I have an installer who said "just bring it all in and we'll make it work." So the tires are on their way, Continental 225/55r16s to match with ACT mesh wheels.

BTW these are the rims, see pic. I am like a kid before Christmas waiting to get them installed. Mid-next-week...

IMG_5402.jpeg

Wow; those are awesome looking wheels. They look a lot like BBS RZs but I’m sure at a fraction of the cost. I love the combination of polished lips with the silver centers. Be sure to post a pic with them mounted on your car!

Haha, yeah thanks I am really fired up to get them on the car. I looked around at a lot of wheels. I mean, a lot. Basically I wore out the internet. These ACMs are classic and true OEM mesh wheels, but just a little something different. And yeah maybe half the price didn’t hurt-

The final outcome shown below. Thanks for all the input. (Let’s be honest: we basically know if they’re gonna rub or not, but we still need peer validation before making the investment. Or at least I did.)

Very nice!

Stunning yet elegant. Perfect complement to the E24's styling.

LarryM wrote: ↑Wed Sep 28, 2022 5:47 pm Stunning yet elegant. Perfect complement to the E24's styling.

+1

I would be extremely proud of that setup

Ralph