Will M2 competition 788M fit E86M?

[Mos6689]

Sorry I’m useless with this, no matter how much I read I can’t get my head around calculating this myself.

Car is stock at the moment but will probably be going down the Bilstein B12 route at some point. Will these wheels fit now and after suspension change? Found a spec sheet on the M2 19” wheels below, someone please help me work this out and possibly give me a dumbed down explanation if you have time.

Thanks

 

[Ed Doe]

https://www.willtheyfit.com/index.php?width=225&aspect=45&diameter=18&wheelwidth=8&offset=42&width2=245&aspect2=35&wheel_size=19&wheel_width=9&offset2=29

Fronts will poke out more but rolling radius looks very similar and clearance between inside face of the alloys and the strut is unchanged vs stock.

Hang on I'll check rears now
Edit:

Rears look like an issue in terms of clearance between inner face and strut. They don't 'poke' out of the arches as much as oe in fact, so you may be able to run spacers to get them fitting right.


If you can hang on till the morning I'll run my apex ec-7 specs as a comparison and show you what you can fit - or if you want you can run the numbers :.
My setup fits fine, but the rear arches are slightly tickled I think - 18x8.5 ET35 with 245/40/18 on the front and 18x10 ET25 with 265/40/17 on the rear.

Few pics of mine to show the fitment:

 

[Mos6689]

https://www.willtheyfit.com/index.php?width=225&aspect=45&diameter=18&wheelwidth=8&offset=42&width2=245&aspect2=35&wheel_size=19&wheel_width=9&offset2=29

Fronts will poke out more but rolling radius looks very similar and clearance between inside face of the alloys and the strut is unchanged vs stock.

Hang on I'll check rears now
Edit:

Rears look like an issue in terms of clearance between inner face and strut. They don't 'poke' out of the arches as much as oe in fact, so you may be able to run spacers to get them fitting right.


If you can hang on till the morning I'll run my apex ec-7 specs as a comparison and show you what you can fit - or if you want you can run the numbers :.
My setup fits fine, but the rear arches are slightly tickled I think - 18x8.5 ET35 with 245/40/18 on the front and 18x10 ET25 with 265/40/17 on the rear.

Few pics of mine to show the fitment:
IMG_20200503_162627.jpg
IMG_20200503_162548.jpg
IMG_20200503_162605.jpg

Thanks Ed. I found a “calculator” online and put in the specs. Not quite sure what to make of it though. The fronts say they poke out 25mm further. Worried this will mean it rubs on the arch?

Rears look like they’re very close to the strut but as you said a spacer could solve that but then does that mean it’s going to poke out and rub the arch as well? I’m leaning towards saying no as everyone tends to run 10/12 or 10/15 spacers. My main concern now is once lowered on eibachs is it going to cause a big issue? Front gets lowered by 20mm and rear 10mm.

 

[Ed Doe]

Ok, so I'm using my wheels as a reference point becuase I know they fit (bear with me here).

I plugged my specs vs OE wheels into the willtheyfit calculator.

My Rears (18 x 10J) poke out 18mm more than stock, and the inner face is 8mm closer to the strut, and they fit fine with minor rolling of the inner lip of the arch. So with the M2 Comp 19s, if you ran a 15mm spacer at the rear, you'd end up with similar overall offset to my rear setup - ie. inner face would then be 7.7mm closer to the strut, and wheel would 'poke' out of the arch 17.7mm more than before. So that should fit but I do think you'd probably need to just get the inner lip of the arch rolled so it's not a sharp edge.

Fronts I think may be the issue.....
My Fronts (10 x 8.5J) poke out 14mm more than stock wheels. The inner face is further away from the strut than stock too (by 0.7mm).
Currently on the road I get (with pretty firm coilovers) no contact between tyre and arch liner, however on track where corner loads are higher, I did notice a bit of rub I think, just behind that stupid fragile bumper clip that always breaks when you try and remove the bumper - so it looks like the tyre is contacting the arch liner a little there under heavy corner loads.

I am currently considering running 10mm spacers but have yet to take the plunge as I'm worried they wont fit, or will rub lots on track....

That being said, I do know in the US with the help of camber adjustable top mounts, and possibly modification/removal of the front arch liners, they do run 9.5j fronts on our cars... Pic below for proof! So it has to be possible, I guess it just boils down to how much you want to muck around modifying the car to make them fit?


One question from me - do you think the M2 Comp wheels will look good on the Z4 - with no dish at all? The offset numbers imply they'll be quite 'flat faced', which might not suit the Z4... Style is totally subjective I fully appreciate that, just a thought though!

 

[Mos6689]

Thanks again Ed. Appreciate you taking the time to check that, huge help having someone to reference off.

It looks like I’m going to have deal with rubbing of some sort if I went for these. I know it can be sorted but I don’t want to start rolling the arches & playing with camber to fit them.

In regards to the design. Yea I get what you’re saying completely and it does make me think twice everytime I look at a set but CSL’s have been slaughtered, for good reason because they sit perfectly on this car but I like having something different. Hence getting an E86 in the first place. Not sure what else to go for? Wanna stay BBS or BMW for build quality ideally.

 

[Ed Doe]

Thanks again Ed. Appreciate you taking the time to check that, huge help having someone to reference off.

It looks like I’m going to have deal with rubbing of some sort if I went for these. I know it can be sorted but I don’t want to start rolling the arches & playing with camber to fit them.

In regards to the design. Yea I get what you’re saying completely and it does make me think twice everytime I look at a set but CSL’s have been slaughtered, for good reason because they sit perfectly on this car but I like having something different. Hence getting an E86 in the first place. Not sure what else to go for? Wanna stay BBS or BMW for build quality ideally.

Pleasure chap, glad I could help!

Yeah I know what you're saying re CSLs - they do look great but been done to death!

I'm completely biased but I do like Apex alloys - the cut a nice 'oem+' look if that makes sense? Arc-8s look similar-ish in design to CSLs I guess, and they've been done a lot on BMWs recently, but EC-7s (the ones I have) are fairly rare on Z4s, and I don't think I've seen any wearing SM-10s!

Otherwise, wierdly I think there are some Japanese alloys which do work with the Z4 - take a peek at the alloys on driftworks - I reckon some of the work ones would look ace!

 

[Mos6689]

Update which may come in useful for anyone who may consider putting these wheels on in future. A friend who works at a dealership got an M2 Comp in this week, with the 788M wheels I was considering. Had a chance to try them and it won’t work. Rears ware very tight, as Ed said above. Not massively but arches may well need rolling depending on if I lowered I think. Fronts are just not gonna work period.

Looks like I’m going down the CSL path after all. Wanted something different but there isn’t really anything else out there that these cars can sit on that looks as clean & well suited. Found a place called CS wheels in the UK and they do ultra concave 10J rears for the M which should look awesome & the offset allows me to put them on without worrying about spacers. Something I’d ideally like to avoid because I just don’t like using spacers. I just feel like it compromises something somewhere, having a metal plate between wheel and hub just screams stress on the hub/suspension components which must have some sort of an effect on handling in some way (I have limited knowledge so is probably just ocd kicking in).

The setup im now going for on the rear looks like the pic below. Pokes out a couple mm more than the M2 rims but offset is pretty much spot on. Ed you mentioned you’re on coilovers, how much lower than stock are you?

 

[Darkangelv2]

Update which may come in useful for anyone who may consider putting these wheels on in future. A friend who works at a dealership got an M2 Comp in this week, with the 788M wheels I was considering. Had a chance to try them and it won’t work. Rears ware very tight, as Ed said above. Not massively but arches may well need rolling depending on if I lowered I think. Fronts are just not gonna work period.

Looks like I’m going down the CSL path after all. Wanted something different but there isn’t really anything else out there that these cars can sit on that looks as clean & well suited. Found a place called CS wheels in the UK and they do ultra concave 10J rears for the M which should look awesome & the offset allows me to put them on without worrying about spacers. Something I’d ideally like to avoid because I just don’t like using spacers. I just feel like it compromises something somewhere, having a metal plate between wheel and hub just screams stress on the hub/suspension components which must have some sort of an effect on handling in some way (I have limited knowledge so is probably just ocd kicking in).

The setup im now going for on the rear looks like the pic below. Pokes out a couple mm more than the M2 rims but offset is pretty much spot on. Ed you mentioned you’re on coilovers, how much lower than stock are you?

If you used the tyres that come on the M2 wheels, you're right, there's no way.

I've got identical wheels (437M) and they fit lovely on the rear (255/35) and are a bit pokey/stretched on the front (225/35). I'm going to change to 235 on the front which should remove the stretch and am trying to find a machine shop to take 3-5MM off the inside face to make them just right.

That said, they absolutely do fit without rubbing at the moment (I run BC Coilovers slightly lowered with CSL alignment).

 

[Ed Doe]

Update which may come in useful for anyone who may consider putting these wheels on in future. A friend who works at a dealership got an M2 Comp in this week, with the 788M wheels I was considering. Had a chance to try them and it won’t work. Rears ware very tight, as Ed said above. Not massively but arches may well need rolling depending on if I lowered I think. Fronts are just not gonna work period.

Looks like I’m going down the CSL path after all. Wanted something different but there isn’t really anything else out there that these cars can sit on that looks as clean & well suited. Found a place called CS wheels in the UK and they do ultra concave 10J rears for the M which should look awesome & the offset allows me to put them on without worrying about spacers. Something I’d ideally like to avoid because I just don’t like using spacers. I just feel like it compromises something somewhere, having a metal plate between wheel and hub just screams stress on the hub/suspension components which must have some sort of an effect on handling in some way (I have limited knowledge so is probably just ocd kicking in).

The setup im now going for on the rear looks like the pic below. Pokes out a couple mm more than the M2 rims but offset is pretty much spot on. Ed you mentioned you’re on coilovers, how much lower than stock are you?

Hi Mate,

Sorry didn't see your latest post till just now!

I'm not entirely sure how much lower I am than stock but it's certainly not obscene - there's still plenty of clearance for speed bumps etc. Can't really help beyond that sorry! Pic below if it helps!



Out of interest, fitting spacers does have advantages but also disadvantages - generally they can increase load on the wheel bearings, and on the front modify the scrub radius which can introduce some undesirable handling traits, but correspondingly increasing track does improve grip at the corrseponding axle.

All of this is relative though - if you fitted 10mm spacers I highly doubt you'd notice any distinct negatives, and wouldn't place much additional load on the bearings - I ran 10mm spacers on the front of my 3.0si coupe for years (needed to clear the upgraded brake kit), including on several trackdays and never noticed any negative effects on the handling!

The dishy 10j's you've found sound very tasty, got any pics?!

 

[Mos6689]

Yea I get what you mean regarding spacers and I’ve used them in the past when I’ve had no choice. But ideally always try to avoid using them if possible.

Just fitted the tyres on the wheels today after letting the ceramic coat cure. Went for 265/35 on rears & 235/40 on the fronts. Went for these sizes for three reasons. Firstly it’s the closest to OEM in regards to rolling radius & speedo error. Secondly, it raised the car a few mm’s, rather than lowering it because I plan to lower it in the future. Finally I didn’t want to go down to 35 & 30 profiles because I’m worried the ride will be unbearably harsh. I’m used to stiff feeling cars & don’t mind them but the Z4 in general is close to my tolerance of how stiff I can go for a DD, without adding low profile tyres to completely kill it.

Fronts rub when on full lock, literally just, against the back on one side & front where the removable hatch for the headlights are. Looked again at the other two options, which were 275/30 or 265/30 on the rear & 245/35 or 235/35 fronts. The difference to OEM spec is what’s putting me off. It may sort out the rubbing, but I think I can live with it and just not go full lock by a quarter turn to prevent rubbing. Let alone having to fork out for a new set of tyres again. Rears are tight as hell but I didn’t experience any rubbing on the drive home. Will take it for a longer blast tomorrow and see.

The only thing that is annoying is unless I go low profile on the tyres next time around, I don’t think I can lower the car. My main reason for wanting to lower the car was to change the awful OEM springs they came with. I’m pretty sure the answer is no but is there an aftermarket upgraded set of springs that don’t lower the car & are more reliable than BMW?

 

[Ed Doe]

Yea I get what you mean regarding spacers and I’ve used them in the past when I’ve had no choice. But ideally always try to avoid using them if possible.

Just fitted the tyres on the wheels today after letting the ceramic coat cure. Went for 265/35 on rears & 235/40 on the fronts. Went for these sizes for three reasons. Firstly it’s the closest to OEM in regards to rolling radius & speedo error. Secondly, it raised the car a few mm’s, rather than lowering it because I plan to lower it in the future. Finally I didn’t want to go down to 35 & 30 profiles because I’m worried the ride will be unbearably harsh. I’m used to stiff feeling cars & don’t mind them but the Z4 in general is close to my tolerance of how stiff I can go for a DD, without adding low profile tyres to completely kill it.

Fronts rub when on full lock, literally just, against the back on one side & front where the removable hatch for the headlights are. Looked again at the other two options, which were 275/30 or 265/30 on the rear & 245/35 or 235/35 fronts. The difference to OEM spec is what’s putting me off. It may sort out the rubbing, but I think I can live with it and just not go full lock by a quarter turn to prevent rubbing. Let alone having to fork out for a new set of tyres again. Rears are tight as hell but I didn’t experience any rubbing on the drive home. Will take it for a longer blast tomorrow and see.

The only thing that is annoying is unless I go low profile on the tyres next time around, I don’t think I can lower the car. My main reason for wanting to lower the car was to change the awful OEM springs they came with. I’m pretty sure the answer is no but is there an aftermarket upgraded set of springs that don’t lower the car & are more reliable than BMW?

Looking very smart!

What width are those alloys front and rear?

I'm surprised you're getting rubbing at the front, I'm running 245/40 profile on the front, and mine is lowered with only minor rubbing as I said on track really.... are you planning to get the car aligned? If so I recommend getting rid of the camber pins on the top mounts and getting a bit more camber adjustment at the front. CSL Alignment is a lovely setup for fast road driving in my experience, and might well help with any rubbing.

In terms of Aftermarket springs - I think Suplex are the choice for OE ride height, but I don't have much experience in that department!

 

[Mos6689]

Thanks, they’re 8.5J front 235/40 and 10J 265/35 rear. Are your running the same width on the front without rubbing? If so I definitely need to get that csl alignment done! I see you mentioned TWG in camberely in another post for CSL alignment. I’m in Guildford so that’s not too far at all to travel. I don’t mind the way the car handles now, apart from the harsh ride, which even then is a lot better on the new tyres. So am I going to dislike what the csl alignment gives?

Was thinking to add 5mm spacers but if alignment can sort it out that’d be great.

Yea I did find suplex mentioned in another post but they only do replacements for non M Z4’s. Not M’s.

 

[Ed Doe]

Thanks, they’re 8.5J front 235/40 and 10J 265/35 rear. Are your running the same width on the front without rubbing? If so I definitely need to get that csl alignment done! I see you mentioned TWG in camberely in another post for CSL alignment. I’m in Guildford so that’s not too far at all to travel. I don’t mind the way the car handles now, apart from the harsh ride, which even then is a lot better on the new tyres. So am I going to dislike what the csl alignment gives?

Was thinking to add 5mm spacers but if alignment can sort it out that’d be great.

Yea I did find suplex mentioned in another post but they only do replacements for non M Z4’s. Not M’s.

I'm running 8.5j fronts with 245/40 tyres, and no rubbing! Mine has adjustable camber top mounts and a little more camber than OE though that's the only thing!

Didn't realise you're in Guildford, so am I :lol: If you fancy coming over to actually have a look at mine and/or go for a spin you're more than welcome

Yeah Will @ TWG has always been brilliant for me, I've used him for my si coupe and then my M since 2014 - he's a lovely chap and very knowledgeable
In terms of alignment, it makes it a bit pointier at the front end, and gives less tendency to understeer near the limit, so makes it more neutral and enjoyable to drive. It's not like a WILD difference from OE, it just makes the car more neutral, which (in my opinion) is more pleasant to drive quickly

Didn't realise Suplex didn't do springs for the M's - shows what I know about OE springs :lol:

 

[Mos6689]

I thought I recognised that background in that side profile pic you posted earlier in the thread. Looks like screwfix in slyfield small world! I might take you up on that offer when I come to do the alignment. Need to refresh my bushes first. Going to go down to Ross at RBM soon hopefully. Getting a very faint steering wobble/vibration at motorway speeds which is bugging me.

Been banging my head as to how yours doesn’t rub on full lock. I can’t see how camber makes that much of a difference on full lock on the fronts when picturing it in my head. I very well may still not be getting it. Always just bought wheels, matched the stud fitment and chucked them on, never gone this in depth.

Only thing I was just drawn back to is the offset of the alloys, yours is ET35 & mine ET45. I think that 10mm is literally the difference between rubbing and not rubbing. Thinking the only way to stop it, is to use a 5mm spacer on the fronts & hope that’s enough. It’s hard to gauge if 5mm is going to be enough when looking at where it touches. I suppose even if it doesn’t stop the rubbing completely, it’ll still give me more clearance than it currently has. I think going 10mm is going to make the wheel poke out of the arch, because these new wheels already sit a further 14mm out vs the 224’s.

Must admit it I’m starting to regret this tyre size choice. Should’ve gone 245/35 & 275/30. Clearance wouldn’t of been an issue then, front or back. Mind you 275 would’ve had extra poke out of the arch, depending on tyre manufacturer. At the moment the poke on the rears is on the absolute limit of acceptable IMO. new wheels are supposed to be a joyous thing, this is just painful atm!

 

[Ed Doe]

Quick one cause I'll reply properly later but if you want to very quickly check if 5mm spacers will help I have some 5mm non-hubcentrics in the shed. You can't drive on them because you can't locate the wheel properly on the centre bore but you will know for sure if the wheels rub on lock? Pm me you're welcome to pop by and try them

 

[mr wilks]

Yea I get what you mean regarding spacers and I’ve used them in the past when I’ve had no choice. But ideally always try to avoid using them if possible.

Just fitted the tyres on the wheels today after letting the ceramic coat cure. Went for 265/35 on rears & 235/40 on the fronts. Went for these sizes for three reasons. Firstly it’s the closest to OEM in regards to rolling radius & speedo error. Secondly, it raised the car a few mm’s, rather than lowering it because I plan to lower it in the future. Finally I didn’t want to go down to 35 & 30 profiles because I’m worried the ride will be unbearably harsh. I’m used to stiff feeling cars & don’t mind them but the Z4 in general is close to my tolerance of how stiff I can go for a DD, without adding low profile tyres to completely kill it.

Fronts rub when on full lock, literally just, against the back on one side & front where the removable hatch for the headlights are. Looked again at the other two options, which were 275/30 or 265/30 on the rear & 245/35 or 235/35 fronts. The difference to OEM spec is what’s putting me off. It may sort out the rubbing, but I think I can live with it and just not go full lock by a quarter turn to prevent rubbing. Let alone having to fork out for a new set of tyres again. Rears are tight as hell but I didn’t experience any rubbing on the drive home. Will take it for a longer blast tomorrow and see.

The only thing that is annoying is unless I go low profile on the tyres next time around, I don’t think I can lower the car. My main reason for wanting to lower the car was to change the awful OEM springs they came with. I’m pretty sure the answer is no but is there an aftermarket upgraded set of springs that don’t lower the car & are more reliable than BMW?

A 225 40 18 front tyre will most likely cure your problem with virtually no visual difference , adding a spacer of any size will only worsen your predicament .
Once you have reached the point of contact its literally down to a matter of mm's between no rub & contact .
Even the new rubber 8mm+ against part worn 5mm can be the difference as can tyre brand ( Michelin being fuller than say a Conti6 or new PZero which both seem to have a slightly rolled outer shoulder compared to PS4s )

 

[Ed Doe]

Having woken up a bit since my last reply, agree with Mr Wilks - adding 5mm spacers will push the wheels out more so increase the rubbing. I'm really confused as to why my setup works and yours doesn't, my tyre profile is taller, width is greater, and offset is 10mm more aggressive, and there are no mods to the arches at the front, just the adjustable camber top mounts. I'll dig out my latest geo settings later to see if that sheds any light on it.