17" wheels for Z3- what offset?

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torrente
Joined: Fri 09 Oct, 2015 19:07
Posts: 7

  Z3 roadster 1.9

17" wheels for Z3- what offset?

Post by torrente »

Hello,

I'm running on 225/50 r16, 7J, ET 40...wheels that I want to put on are 9,5 x17 (front) and 10,5x17 (rear), with 225/40/17 (front) and 245/40/17 (rear)

Offsets for 9,5" are 12, 20 and 2 mm, and for 10,5" are -10, 0 and 2 mm

which offsets should I choose? Are all the offsets good, or some will not fit maybe? (I've been on willtheyfit, it just calculates how much the rim will stick out, but I dont know if the tires will rub the fenders or something)

p.s. car is lowered 30 mm front and rear
deni2s
Joined: Mon 25 Mar, 2013 22:02
Posts: 761

  Z3 roadster 2.8

Re: 17" wheels for Z3- what offset?

Post by deni2s »

Any of these offsets will stick out too much with these widths.

P.S. Don't lower your car until you know which offsets you need.
Brian4
Joined: Mon 19 Dec, 2011 19:02
Posts: 541

  Z3 roadster 3.0i
Location: Hinckley

Re: 17" wheels for Z3- what offset?

Post by Brian4 »

You can use this to see what effect changing wheels does to the outside position of the tyre.

I your example the fronts will stick out 52mm more than now with the 20mm offset and the others will be worse the rears are 75mm stick out with the 10mm offset.

http://www.willtheyfit.com/index.php?wi ... 10#content
Brian
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torrente
Joined: Fri 09 Oct, 2015 19:07
Posts: 7

  Z3 roadster 1.9

Re: 17" wheels for Z3- what offset?

Post by torrente »

ok can someone please explain me how much can tire stick out of proportions, which dimensions would you use to get the widest wheel and still not sticking too far out (how far is too much?)
Antm72
Joined: Fri 01 May, 2015 13:53
Posts: 75

  Z3 roadster 2.8

Re: 17" wheels for Z3- what offset?

Post by Antm72 »

Standard offset is 41 front wheel a 7.5 j normally , you can stretch as far as an 8j front but not much lower than a 35 offset at this you may need to put a little stretch on the tyres.
I run 7j all round with a 35 offset it is about 12mm further out but tyre tread still under the arch.
The rear depending on model of zed has a little more scope i run the same 35 offset with a 20mm spacer on a widebody prefacelift and they fit under the arch now lowered and just out side again tread in on standard suspension.
The lower the offset number the further out the wheels will sit you must take into account rim width too as its equally important.
If you stick the stock measurements onto the calculator in the link then add your new fitment you will see the effect it will have.
Image
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Inferno
Joined: Sun 30 Sep, 2012 07:35
Posts: 277

  Z3 roadster 1.8
Location: Athens

Re: 17" wheels for Z3- what offset?

Post by Inferno »

Antm72 wrote:Standard offset is 41 front wheel a 7.5 j normally , you can stretch as far as an 8j front but not much lower than a 35 offset at this you may need to put a little stretch on the tyres.
I run 7j all round with a 35 offset it is about 12mm further out but tyre tread still under the arch.
The rear depending on model of zed has a little more scope i run the same 35 offset with a 20mm spacer on a widebody prefacelift and they fit under the arch now lowered and just out side again tread in on standard suspension.
The lower the offset number the further out the wheels will sit you must take into account rim width too as its equally important.
If you stick the stock measurements onto the calculator in the link then add your new fitment you will see the effect it will have.
I agree, i run 8J ET35 - 225/45-17 at front and it is pretty much on the edge.
torrente
Joined: Fri 09 Oct, 2015 19:07
Posts: 7

  Z3 roadster 1.9

Re: 17" wheels for Z3- what offset?

Post by torrente »

I haved narrowed my search to these dimensions: 8.5x17 (front) and 9.5x17 (rear)...front tires: either 215/40 for stretched look or 225/40...rear tires: 235/40 or 245/40....would that be ok to fit? would those dimensions be too streched on those tires (215 front, 235 rear), aka poor ride?
Antm72
Joined: Fri 01 May, 2015 13:53
Posts: 75

  Z3 roadster 2.8

Re: 17" wheels for Z3- what offset?

Post by Antm72 »

A 225 on an 8.5 is a mild stretch, i had 225's fitted all round on a 7.5/ 8.5 staggered set up and it was fine at 8.5 front i would be looking at et 38 or higher. I fitted an 8.5 41 offset to the front of my zed was a bit on the edge for me but if a stance look and stretch is your aim you will be ok.
Image
torrente
Joined: Fri 09 Oct, 2015 19:07
Posts: 7

  Z3 roadster 1.9

Re: 17" wheels for Z3- what offset?

Post by torrente »

so 8.5 front and 9,5 rear I should fit in without problems? adjustments, offsets?

thank you all!
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Inferno
Joined: Sun 30 Sep, 2012 07:35
Posts: 277

  Z3 roadster 1.8
Location: Athens

Re: 17" wheels for Z3- what offset?

Post by Inferno »

No, imo 8.5 at front needs something like ET41 as antm72 said. An 8.5 with ET35 for example would be rubbing the tire to the arches perhaps even with a 215 (that also depends on how lowered the car is). If you want to put 8.5J at front you should really choose ET40

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c_w
Joined: Thu 19 Aug, 2004 16:50
Posts: 4032

  M roadster S50

Re: 17" wheels for Z3- what offset?

Post by c_w »

225/40/17 doesn't exist, but you can get 225/35/17 is some tyres.

I run a 215/40/17 on a 8.5J, here's how it looks;

Image
Wheel on the left is a 10x17 with a 245/35/17, the one on the right is 8.5x17 with 215/40/17. The 245/35/17 tyre is fractionally smaller in sidewall and can look a bit undertyred in the rear arch.

Image

Image

A 215/40/17 is actually "permitted" to fit on a 8.5J rim by tyre manufacturers so isn't extreme.

A 235/40 on the rear would be a better match on a 9.5J in terms of slight stretch.
torrente
Joined: Fri 09 Oct, 2015 19:07
Posts: 7

  Z3 roadster 1.9

Re: 17" wheels for Z3- what offset?

Post by torrente »

great post c_w, thank you!...so, 215/40/17 with 8.5" front and 235/40/17 with 9.5" it is....now just need to match right offsets, but that's a homework for my tuner :)
deni2s
Joined: Mon 25 Mar, 2013 22:02
Posts: 761

  Z3 roadster 2.8

Re: 17" wheels for Z3- what offset?

Post by deni2s »

IMHO perfect setup on wide body z3 on stock suspension is as follows:

8.5J et33 with 225/45 fronts
10J et33 with 245/40 rears

That is what Clauss from felgen-garage.de recommended me when I ordered my wheels and I am very happy with that advice. Wheels are a little bit stretched, but not very much.

Image

Flush with the arches, nothing sticks out, no rubbing or other issues.
Image

Lowered car might require even less ET.
torrente
Joined: Fri 09 Oct, 2015 19:07
Posts: 7

  Z3 roadster 1.9

Re: 17" wheels for Z3- what offset?

Post by torrente »

Car is not going to be on stock suspension, will be lowered soon with Bilstein B12 pro kit (30 mm front and rear)

looks great deni, sizing is good, 8.5 front and 10.0 rear is almost what i aim on, but I would like to have a bit more stretch, so that's why maybe would go with a bit narrower tyres, 215 front and 235 rear..also, trying to close the gap between tyres and the body as much as possible...

are those 17 or 18"?
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c_w
Joined: Thu 19 Aug, 2004 16:50
Posts: 4032

  M roadster S50

Re: 17" wheels for Z3- what offset?

Post by c_w »

I don't particularly like 225/45/17 tyres, they look a bit too tall sometimes, particularly when paired with the slightly smaller radius 245/40/17 tyre. I know 225/45 and 245/40 is stock BMW size, but they are actually not the same diameters - a 255/40/17 actually matches almost exactly a 225/45/17.

215/40 and 235/40 should suitably low profile but still fit right and not look daft IMO.
deni2s
Joined: Mon 25 Mar, 2013 22:02
Posts: 761

  Z3 roadster 2.8

Re: 17" wheels for Z3- what offset?

Post by deni2s »

torrente wrote:Car is not going to be on stock suspension, will be lowered soon with Bilstein B12 pro kit (30 mm front and rear)

looks great deni, sizing is good, 8.5 front and 10.0 rear is almost what i aim on, but I would like to have a bit more stretch, so that's why maybe would go with a bit narrower tyres, 215 front and 235 rear..also, trying to close the gap between tyres and the body as much as possible...

are those 17 or 18"?
17" ACS Type 1 wheels. I plan to lower it by 30mm, I will go with ACS sport suspension (Bilstein B8 + ACS springs), but probably next season.
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