Z4-forum.com

I’m the proud owner of a 2009 Sdrive 35i..... and absolutely loving the experience 4 weeks in.

I have a probably stupid question about wheel sizes, that hopefully someone can answer.

I’m currently running 326s, as a staggered set, with the following configuration

Fronts - 225/35/R19
Rears - 255/30/R19

The wheels need to be refurbished, and I’ve been thinking of putting some ‘winter’ wheels and tyres on whilst they’re being done, leaving me to use her deeper into the winter.

I’ve been looking around and am looking at 17s or 18s, mostly non staggered. I’m aware that the tyre sizes will change as the rim sizes do.

My question is, if I buy a set of straight wheels and tyres, will they be a straight replacement, or will there be something else i need to consider?

I’d be aware of the size of the front brakes, 17’s might not have enough clearance for the caliper
Rob

All wheels should be straight, or round, depending on how you look at it.

The term you are looking for is Staggered setup vs. square setup.

Are you thinking less width at the rear or more width at the front? Neither should cause any issues depending on the severity or the difference.

I’ve gone up an inch front and back and have less rubbing than I did before!

Thanks for the responses.

I guess that’s probably the question I’m asking Steve. I’d figured I’d end up with a set of ‘square setup’ wheels and tyres, in whatever size they come.

Had a look at one of the tyre size calculators on Kwikfit and it gave me several sizes that could fit on the car.

It’s more about what the implications are for putting narrower wheels on the rear I suppose?

Check the label in the drivers door frame. It will list the tyre sizes for your car, and from that you can see is staggered or square are ok.

AFAIK you can fit BMW OEM Z4 17" wheels on the 3.5i.

In the states and other countries 17" square set of wheels was commonplace, in part to get over the MSPORT suspension ride issues..

The calipers on the 3.5i are smaller than the 3.5is.

I'm running asymmetric summer wheels and square winter wheels all 17"

In theory a good supplier of after market wheels should be able to tell whether they will fit or not to your specific model..

Pbondar wrote: ↑Sun Nov 19, 2017 1:24 pm AFAIK you can fit BMW OEM Z4 17" wheels on the 3.5i.

In the states and other countries 17" square set of wheels was commonplace, in part to get over the MSPORT suspension ride issues..

The calipers on the 3.5i are smaller than the 3.5is.

I'm running asymmetric summer wheels and square winter wheels all 17"

In theory a good supplier of after market wheels should be able to tell whether they will fit or not to your specific model..

I was under the impression 17’s wouldn’t fit the 3.0si, thought the brakes on a 35i would be larger than those?
Rob

It depends on the wheel surely?

There is no problem running a square (or non-staggered) set-up with winters on OP.

My E46 Sport Compact runs 17 inch rims on summers - 7.5J front with 225/45 tyres and 8.5J rears with 245/40 tyres, but a 16 inch square set of 7J rims in winter with 205/55 tyres (which is what SE models had as standard anyway).

I don't know what will work on a 35is, but as has been said you need enough diameter to clear the front brakes - and equally crucial is that the offset (or ET) needs to be somewhere close to original to avoid any rubbing on suspension or wheel-arches.

326 wheels seem to be 8J fronts with ET29 and 9J rears with ET40 so I'd probably be looking for 18s with offsets as close to those as possible.

The 2012 BMW UK price list shows the 3.5i sold with 17” staggered alloy wheels as standard..

17" light alloy Turbine-spoke style 292

Pbondar wrote: ↑Sun Nov 19, 2017 1:24 pm

The calipers on the 3.5i are smaller than the 3.5is.

Don.t think this is true On Euro cars all the twin turbo 35s have same brakes . Think earlier Se 35i US models may have had discs + calipers from the Na 30i .

If the offsets are right I see no issue fitting 17inch alloys on 35i or 35is whether square or staggered .

mr wilks wrote: ↑Mon Nov 20, 2017 11:20 am

Pbondar wrote: ↑Sun Nov 19, 2017 1:24 pm

The calipers on the 3.5i are smaller than the 3.5is.

Don.t think this is true On Euro cars all the twin turbo 35s have same brakes . Think earlier Se 35i US models may have had discs + calipers from the Na 30i .

If the offsets are right I see no issue fitting 17inch alloys on 35i or 35is whether square or staggered .

Mr Wilks is correct it would appear...

Real EOM for a 2009 US 3.5i Z4
Front brakes
330x24 Disc RH Caliper 34116769094
Rear Brakes
300x20 disc RH caliper 34206786058

Real OEM says for a UK 2012 Z4 model
Front brakes
3.5i
348x30 disc RH caliper 34116773202
3.5is
348x30 disc RH caliper 34116773202

Rear Brakes
3.5i
324x20 disc RH caliper 34206786068
3.5is
324x20 disc RH caliper 34206786068

So if you can fit 17" wheels to a 3.5i then a 3.5is can have 17" wheels too it would appear...

It would appear that you could add the 3.5i/3.5is brake bits to a 4 pot Z4 if you wanter more brakes too?

Firstly, thanks once again for all of the responses. It’s great to belong to a forum where newbies aren’t ridiculed for asking questions.

I’ve read and reread the posts above, and think that, in summary, there’s nothing preventing me from running my Zed on 17’s.

I’ve been offered a set of alloys from an F30 3 series. They’re a set of 396’s running 225/45/18 tyres. I can see these tyres listed on the sticker inside the door, so the tyres are good.

The wheels are 8jx18’s with an offset of 34. I’m a little confused with the offset requirement. As my current wheels have a staggered offset (ET29 and ET40), when choosing a straight set would these wheels with an ET34 offset be ok, or would I have problems?

Many thanks again in advance.....

You might need a small spacer on the front presuming the wheels are the same width.