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[thez99]

So right now I'm just running the stock setup on my 13' 135i, 18x7.5F at 215/40/18 and 18x8.5R at 245/35/18. I've been looking for a set of wheels I love at a staggered setup but I just can't seem to find one. I had a set of vmr 701's on my previous 1er but I ran into rubbing issues with them being 9.5" in the rears, not to mention theyre not cheap and they're heavier than the stock rims. I'm not looking to beat my fenders up nor will I be modding the suspension at all except for possibly upgrading to M3 front upper lower control arms.

So I'm looking at a square setup but I need some tips on making it work correctly with no rubbing. There's a few rims I've seen I could run square on, one is an 18x8.5 43et (konig freeforms) and I'd assume a 235/40/18 tire, I wouldn't want to run anything less on the rears especially. Curious if this would run no problem, would I have any room to spare front or back?

To be honest I would rather run a staggered setup on a RWD car but you also lose the ability to property rotate your tires with that, and also obviously preferable rim setups are hard to find. Is there any other real benefit to the staggered setup we run? I'm also def wanting a wider tire up front vs stock setup to somewhat undo the understeer.

[b1aze]

https://support.apexraceparts.com/hc...-Fitment-Guide

Very thorough guide to each fitment type.

[ShocknAwe]

Huge variety of fitments can be had with apex fitments or custom wheels.

For reference, I have 275/35 out back on stock 135i rear fenders with a tire that runs wide. You could fit a 245 up front or even 255 if you wanted to fiddle with settings and shoehorn it in.

Square, it depends. I'd probably shoot for 245 on stock fenders or 255 if you're willing to accept stock body and suspension modifications, or 275+ if you're willing to do some combo of widebody parts and suspension work.

[thez99]

So you're saying I could work an 18x8.5 43et wheel with a 245/40/18 front and back with no mods and no rubbing?

Wheels are Konig freeforms btw

[Tuxedo]

Originally Posted by thez99

So you're saying I could work an 18x8.5 43et wheel with a 245/40/18 front and back with no mods and no rubbing?

Wheels are Konig freeforms btw

I would recommend going 235/35R18 or 245/35 Square. The diameter of 40 aspect ratio is more than 3%

The amount of understeer going to a square set with that much sidewall you also might find feels sloppy

[thez99]

Originally Posted by Tuxedo

I would recommend going 235/35R18 or 245/35 Square. The diameter of 40 aspect ratio is more than 3%

The amount of understeer going to a square set with that much sidewall you also might find feels sloppy

235/35 spec tires are basically non-existent...

Also I don't understand your statement about the sloppiness of a 235/40 tire

Going from a staggered to a straight setup should balance things out anyways, not to mention a wider tire up front will help the understeer. Also the stock tire spec up front is already a 40 spec sidewall tire, so what are you trying to say??

[lowside67]

245/40/18 is a very tall (and somewhat unusual) tire size that is not a good choice for the front of your 1 series. Tire fitment is extremely limited on the front of these cars and going with a taller that necessary tire is just making it harder on yourself for no reason.

To make sure you are 100% clear - "40" sidewall is not a size, but rather a percentage. A 215/40/18 is a much shorter tire than a 245/40/18 despite the fact they are both "40" sidewalls.

I ran 235/40/18 square on my car with 18x8.5s all around but this requires a good bit of camber in the front to make sure it doesn't rub. Upgrading to M front control arms will actually make tire fitment worse so no help there.

IMO if you are going to stay stock suspension, stock camber - staggered is the way to go. Yes, the car will continue to understeer, but that is largely due to the close to 0 degrees of front camber and going up a tire size or two will not fix that in any meaningful way.

Not sure why you'd give up rear tire size just for the ability to rotate tires, to me that seems like an inefficient tradeoff.

-Mark

[thez99]

Upgrading to the M3 control arms actually gains -.75 camber so that would help the situation. Check out HPAs site, quite a bit to see about their kits and the benefits.

Also, not sure what offsets you're running with your square setup but 18x8.5's with 235/40 tires are supposed to be basically the perfect setup for this car. No rubbing and no modifying. Offset can't be much below 45.

I get what you're saying about the 245/40 being too tall though. I doubt I would go with 245's as I'd have to run 35 walled tires front and back, be even less shock comfort than stock there. I'm not a comfort hippy with tires but I'm certainly not the kind to run for the slimmest tire and the largest wheel possible either. I'm even considering running a 17.8.5 setup with 235/45 tires, less likely but it's a maybe

[thez99]

Also, tire rotation is very important to me. If I'm going to shell out $1800+ for a wheel tire setup i'm damn well doing so knowing I can rotate them and keep them for at least 40k miles. Shit is not cheap and I can't stand people who swap out random tires at random times because their oddly worn, makes no sense to me physically or financially. A true staggered setup to me really is only necessary if you're driving something like a modded V8 stang or something like that. I'm not running shitloads of power mods on this car, it doesn't need it. The 135i doesn't by any means need a tire wider than 245 on the rear unless you're pushing 450hp and spinning burning rubber every time you hit the pedal.

Also if you're a track devil than perhaps staggered is your thing, but again, that's not me. I'm in it for functionality, overall performance and comfort

[SKI-R]

You were pointed to this Square Setup previously (info is from ApexRaceParts.com), but maybe you missed it....it's pretty definitive.

Front & Rear: 18x8.5" ET45 with 235/40-18 tires
•Popular fitment.
•Available only in ARC-8 and EC-7 designs.
•Direct fit with stock suspension, lowering springs, and a variety of aftermarket coilovers. 5mm front spacers required for certain aftermarket suspensions, see below.
•245/35-18 tires can fit with 5mm front spacers and approximately -1.5 degrees of camber or more. Larger front spacers may be required for certain aftermarket suspensions, see below.
•255/35-18 tires can fit with 5mm front spacers and approximately -2.5 degrees of camber or more. Larger front spacers may be required for certain aftermarket suspensions, see below.
•For a spacer-free fitment, see alternate fitment below.

[thez99]

Yes that's partially the setup I'm referring too. Current wheels i'm looking at are Konig Freeforms that are 18x8.5 et43 front and back and I'd likely run 235/40's all around. Was initially curious if 245/40's would run but it looks like they would be too tall and/or wide for at least the front setup.

These Konigs really are sweet, I've chosen them over the Apex's and VMR's primarily as they're flow formed, lighter and have the sexy 43et perfect offset. Not to mention they're available with a almost pearl bronze finish.

https://www.carid.com/konig-wheels/f...447676955.html

[lowside67]

Originally Posted by thez99

Upgrading to the M3 control arms actually gains -.75 camber so that would help the situation. Check out HPAs site, quite a bit to see about their kits and the benefits.

This is not correct.

Adding negative camber by using camber plates to move the top of the tire inboard will help with fitment.

Adding negative camber by using M arms moves the bottom of the tire outward which makes fitment worse.

You might find this post on my build thread helpful about the impact of control arms on tire fitment:
https://www.1addicts.com/forums/show...5#post21782125

-Mark

255-40-17 RE71R on 17x9 +35 front, +50 rear


235-40-18 ECS on 18x8.5 +35 square

[thez99]

To be honest, I don't know how much stock I can take in your setup/experience versus what I'm speaking of. You have a non-m 128, I have a 13' N55 M sport, different suspension. You're running a much wider wheel and tire setup on the front than I ever would anyways and your build thread speaks to your tires rubbing right after installing your "custom" arms, did you get a correcting alignment done before noticing this? Also, you have custom arms made, are you positive these custom ones are completely different from the M3 ones sold by many including HPA? Did you install both new upper and lower arms?? Perhaps if not this is why you experienced "negative" negative camber??

This is the kit I'm looking at
https://www.hpashop.com/E82-1M-E9x-M...-E9xM3-FCA.htm

https://www.turnermotorsport.com/p-3...2-e9x/?pdk=AwE

[lowside67]

Man, I am trying to help and you are just not listening to me. The 128 and the 135 have the same fenders, uprights, control arms, and strut tower placement - the fact that I started with a 128 base and you have an M sport 135 is 100% immaterial to tire fitment.

Your M sport has stiffer springs/shocks and bigger swaybars from the factory, that is the only difference and neither of those two things make any difference at all to tire fitment.

Let's talk about what the "M control arms" actually do.
https://www.turnermotorsport.com/p-3...2-e9x/?pdk=AwE

That link has two sets of control arms - uppers ("tension arms") and lowers ("camber arms").

The tension arms are exactly the same between a non M and an M car, the only difference is that the rubber bushing at one end is much stiffer in the M version. Therefore, installing these has a near-0 impact on tire fitment since it doesn't actually move the upright differently through its range of motion. I had these exact TRW arms installed in my car to improve the feeling under braking.

The camber arms are the ones that add camber. The reason they do this is because they are LONGER than the non-M arms. Since these mount to the bottom of the upright, they push that upright at the bottom which makes more camber.

In my car, I was not allowed for classing reasons to install the M camber arms. However, by taking my bushing and moving the pivot point, I am effectively doing the same thing which is why adding those arms gave me camber in the same way that adding M arms normally would have. While these are not the same arms, they have the exact same effect.

If you move the bottom of the wheel out (longer camber arms), without moving the top of the wheel in (camber plates), you end up with more of the wheel outside the wheel well, which means you have more tire available to hit the fender lip.

It's not to say it will or will not make the difference between fitting, but the point is M arms add camber which is a good thing for handling, but do not give you more tire clearance.

I hope this helps,
Mark

[thez99]

Yes that makes sense. Hence why some regard this upgrade as the better alternative to simply adding wheel spacers in the front. I'm not planning on pulling the pins or modding/adding camber plates, just not something I feel the need to do. I can understand how some may feel it necessary to achieve better handling for track use, etc. but this is my daily, I don't track the car nor will I ever. The control arm wishbone upgrade would be to plant the car more in braking like you said and in turns, etc. also alleviating some of the hop at higher speeds and correcting some of the understeer.

[thez99]

As it comes to tire fitment, based on reviews and seeing what others have posted, I'm sure the set i'm looking at will fit well. If I stay at 235/40 tires in the rear with a 8.5" wide wheel at 43 offset, I'll more than likely have enough room to add maybe a 3-5mm spacer in the back. Probably a 5mm as they don't make 3mm hubcentric which is a big deal for me, I can't stand using hub rings

[Tuxedo]

Originally Posted by thez99

As it comes to tire fitment, based on reviews and seeing what others have posted, I'm sure the set i'm looking at will fit well. If I stay at 235/40 tires in the rear with a 8.5" wide wheel at 43 offset, I'll more than likely have enough room to add maybe a 3-5mm spacer in the back. Probably a 5mm as they don't make 3mm hubcentric which is a big deal for me, I can't stand using hub rings

I think Mark covered the question on understeer, camber very well in post seven, I also agree there's no need for RWD BMW to have rotations.

And once again I do not recommend 40 aspect ratio for a square set and increasing the size of the tire, go with 245/35 probably won't need spacers however you do have to worry about speed bump, RR track or pothole OEM suspension rebound. Update or upgrade suspension and springs would minimize the issue.

[thez99]

What could anyone's justification be that this car does not need proper tire rotation???

To me that make no sense at all, if you're fine with paying for new tires every 10-15k miles and wearing your current tires all to hell on the outsides screwing up your handling then I guess, but I've still seen no healthy reason why not to have a straight setup and rotate..

Point of my going with a 235/40 is I DONT want to have to worry about my tires beating the hell out of my suspension anytime I go over a bump, nor will I ever max out my front camber by removing the pins and buying expensive camber plates for no reason. Also not sure what site you're getting those numbers from but the two tires I'm looking at do not match those estimates, yes the 40 is a taller tire than is found stock in the rear but there's no reason this wouldn't work, if so why would Apex have this setup at the top of their long loved tire fitment layout?

A 245 could work however yes I would have rubbing issues up front, less shock resistance and absorption all around. It's not that I'm just trying to fight every option known to man, it just seems the two of you can't over this idea of running wider tires than can be had without modifying your fenders and suspension. And again as far as what the car needs for power handling, etc. a 235 wide tire on a 8.5" wheel is more than capable. This has kind of turned more into a battle between modding the fenders and suspension and not.

[thez99]

Also how is it that the 245/35 has a larger section width and tread width but a smaller overall diameter than a 235/40??

[lowside67]

Originally Posted by thez99

Also how is it that the 245/35 has a larger section width and tread width but a smaller overall diameter than a 235/40??

Not sure if serious... I posted this above.

The first number is the width. 245 is bigger than 235, therefore it is wider (in both section width and tread with typically).

The second number is the sidewall height is a % of the width.

245x35% is a smaller number (and therefore is a smaller sidewall, and therefore a smaller overall height tire) than 235x40%.

-Mark

[thez99]

Ok so, fucked on 235/40, and likely fucked on 245/35 for varied rubbing reasons unless I camber the hell out of the front. Right?

Also, still waiting on any great reasoning behind this loyal "no rotation" rule some of you abide by for this car

[lowside67]

It's not that tire rotation is bad, not at all. It's just that the car benefits from more rear tire, it's already easy to overwhelm the rear tires with the power from the turbo - reducing tire width just to be able to rotate the tires isn't a good tradeoff for most people.

-Mark