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Wheel fitment advice


Ekona

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It's no secret the wheels on the BMW aren't exactly hellastance fit: "More tuck than Caitlyn Jenner" has been used to describe them. So I want new ones, however before I push the button can I just run a sanity check past you all please? Long post ahead...

 

Current wheels:

18x8.5J ET45 all round, 245/45/18 tyres

25mm spacer on the front (so essentially ET20)

30mm spacer on the rear (so essentially ET15, extra 5mm needed to clear new suspension)

 

Wanted wheels:

18x8.5J ET25 front 245/45/18

18x9.5 ET22 rear 275/40/18

 

 

Now, on the current setup if I take a straight edge from the tyre lip (two points of contact, top and bottom) to the arch lip I get the following:

10mm gap at the front

15mm gap at the rear

 

In theory then, I can come out an extra 10mm at the front and 15mm at the rear, yeah? So I could run the following:

 

18x8.5J ET25 front with a 15mm spacer (so ET10)

18x9.5 ET22 rear with a 20mm spacer (so ET2)

 

HOWEVER

 

I'm now wider by an inch on the rear, so according to here they would stick out 25mm more than before. Basically, 10mm more than I have space for.

 

For those that have experience, is this something you can overcome by raising the car (temp solution), arch rolling, or even by running more camber? I run very little at the rear, the tyres are pretty much stood upright. If this isn't doable, then I'll just run 8.5J all round and accept I can't really run wider at the rear.

 

What I don't get is that OEM (option) fit on mine is 18x9J ET18, so my puzzle factor is huge here. Shame the BC suspension sit 5mm wider at the rear, but hey ho. As always, thoughts and opinions muchly welcomed. :)

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I'm a bit confused. You want to go from 8.5" ET15 to 9.5" ET2. That's an extra 13mm due to offset, and 12.7mm due to wheel width, so a total of 25 extra mm on the outside, compared with your current set up. So what don't you get?

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Simple option I noticed when considering new wheels for the M6, the "perfect" wheel setup for the Zed is pretty much perfect for the M6, but of course 5x120. 19x9.5/10.5 et20.

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I'm a bit confused. You want to go from 8.5" ET15 to 9.5" ET2. That's an extra 13mm due to offset, and 12.7mm due to wheel width, so a total of 25 extra mm on the outside, compared with your current set up. So what don't you get?

Whether I can lose the extra width via raising the car, or by arch rolling, or by camber.

 

Don't run a huge spacer at the rear, can you reduce it by 10mm? Or are you running that big because of the suspension??

Cannot go any smaller sadly, not even by a single mm. 20mm spacer is nothing, I'm on 30mm as it is!

 

Simple option I noticed when considering new wheels for the M6, the "perfect" wheel setup for the Zed is pretty much perfect for the M6, but of course 5x120. 19x9.5/10.5 et20.

Agreed, but I don't want to move to 19" wheels as it means another outlay on tyres as well as adding weight, even over the spacers.

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I'm a bit confused. You want to go from 8.5" ET15 to 9.5" ET2. That's an extra 13mm due to offset, and 12.7mm due to wheel width, so a total of 25 extra mm on the outside, compared with your current set up. So what don't you get?

Whether I can lose the extra width via raising the car, or by arch rolling, or by camber.

 

Don't run a huge spacer at the rear, can you reduce it by 10mm? Or are you running that big because of the suspension??

Cannot go any smaller sadly, not even by a single mm. 20mm spacer is nothing, I'm on 30mm as it is!

 

Simple option I noticed when considering new wheels for the M6, the "perfect" wheel setup for the Zed is pretty much perfect for the M6, but of course 5x120. 19x9.5/10.5 et20.

Agreed, but I don't want to move to 19" wheels as it means another outlay on tyres as well as adding weight, even over the spacers.

 

Buy M6 wheels then, they'll be lighter than the Rotas and throw the tyres on eBay :p

Edited by KyleR
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I think if you go higher it will look like a monster truck, and if you do the arch rolling and camber you'll be getting a call from Stance Nation. Not sure if that's your aim, but I've never had you down as that type :)

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I'm really not :lol:

 

I've been chatting with Grundy tonight about this, and something here doesn't add up at all. The size of the spacers I have on doesn't join up with me measuring them, the OEM wheel options and widths offered along with their offsets... Something is definitely wrong numbers wise.

 

If you ignore all the guff I posted above and look at the M6 for example, stock wheels there are 19x9.5J ET17 on the rear. Work on the basis I need an extra 5mm clearance due to the suspension and you end up with me needing ET12 on the back: With the new wheels at ET22, I can get that with just a 10mm spacer and even then that puts me at OEM-style wheel fitment! No, this makes zero sense. As such, f*ck it, I'm going to go with my gut and just see what happens.

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So do you need an extra 5mm from standard, or from where you're at at the moment? 9.5" ET22 is more than 5mm clearance for suspension from 8.5" ET45. In your first post you said you needed a further 5mm clearance for suspension, which would mean the new kit would need 35mm over stock suspension as you already have 30mm spacers. How bloody fat are these coilovers?!

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My head hurts. :headhurt:

 

First thing - dont assume that an M6 has the same clearance as you do, it probably has wider arches. Also bear in mind that lower offset means more inner clearance on the same width wheel, so you can reduce the spacer you need to clear the shocks. Finally, arch rolling will grab another 5-10mm of clearance, flaring will add another 5-10mm on top of that, camber maybe 5mm, maybe 10 depending on what you run.

 

The best advice I can give anyone in this situation is to see what others have done and then try a few things yourself, and to that end Turner Motorsport reckon a 9.5 ET22 will go on the back of an E63 .......... :)

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Spacers are not that expensive so worst case you sell the ones you have and buy a different set, as above there are other ways to make them fit unless you go too wide in which case *see below*, that will they fit website is pretty good but can't account for real life suspension/brake snagging issues.

maxresdefault.jpg

Edited by evilscorp
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My head hurts. :headhurt:

 

First thing - dont assume that an M6 has the same clearance as you do, it probably has wider arches. Also bear in mind that lower offset means more inner clearance on the same width wheel, so you can reduce the spacer you need to clear the shocks. Finally, arch rolling will grab another 5-10mm of clearance, flaring will add another 5-10mm on top of that, camber maybe 5mm, maybe 10 depending on what you run.

 

The best advice I can give anyone in this situation is to see what others have done and then try a few things yourself, and to that end Turner Motorsport reckon a 9.5 ET22 will go on the back of an E63 .......... :)

Mine still hurts a day later :lol:

 

Apparently the M6 has the same arches, but a narrower rear track: How that affects clearances etc I don't know. That said, if Turner reckon that'll fit then I can't see I'll have any problems :) Cheers matey!

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My head hurts. :headhurt:

 

First thing - dont assume that an M6 has the same clearance as you do, it probably has wider arches. Also bear in mind that lower offset means more inner clearance on the same width wheel, so you can reduce the spacer you need to clear the shocks. Finally, arch rolling will grab another 5-10mm of clearance, flaring will add another 5-10mm on top of that, camber maybe 5mm, maybe 10 depending on what you run.

 

The best advice I can give anyone in this situation is to see what others have done and then try a few things yourself, and to that end Turner Motorsport reckon a 9.5 ET22 will go on the back of an E63 .......... :)

In simple terms....well I say simple I think I'm going to complicate things.

 

Withs Dans Current - 8.5J ET 45 - He HAS to run a 30mm spacer on the rear to clear the suspension thus ET 15.

 

So he's going up to a 9.5J ET22. - So in theory it he only needs to add 7mm however it's gone up to a 9.5J (extra inch) So that adds 15mm (half inch to rear) closer to suspension.

 

 

 

Okay I complicated things and now my head hurts.

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In my experience this is the best way to do wheels. Take measurements, do your research, ponder for a while then sod it all off, buy the wheels and make them fit.

 

My 350Z was never supposed to be widearch you know ............ :surrender:

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