Z4 roadster 2003 square set up

streetcar · Post by **streetcar** » Thu Feb 23, 2017 9:03 am

Hi all, seeking advice on tyres and in particular running front and rear tyres of the same size.
This is not just for winter / bad weather as I would run this set up regardless of weather conditions.
I have previously received advice from a much respected forum member (on wheels and tyres) that a
245/40/18 set up would be a good neutral/ starting point for all round use and I like the idea of the increase in side wall thickness this size gives.
I'm running standard 108s without spacers on stock suspension ( at least I think it's stock)
Has any member tried this size set up and if so what were the results.
Cheers in advance.
Rgds sd

Scooba_Steve · Post by **Scooba_Steve** » Thu Feb 23, 2017 10:06 am

Bit big up front, as you can't rotate the wheels around I'm not sure what benefit you'd get.
If you are using in all weather then a decent set of winters is a must in my mind.

Marius · Post by **Marius** » Thu Feb 23, 2017 12:19 pm

Mine had 108's with 245/40 pirellis all round. It was OK, car handled good on the track, managed 8:30 on the ring

Scooba_Steve · Post by **Scooba_Steve** » Thu Feb 23, 2017 12:37 pm

Why not just get some equal width wheels? Drop to 17" if you want a bigger sidewall?

Marius · Post by **Marius** » Thu Feb 23, 2017 4:08 pm

Scooba_Steve wrote:Why not just get some equal width wheels? Drop to 17" if you want a bigger sidewall?

There's not much difference better 8 and 8.5 245 tyre sits exactly the same on both.

Scooba_Steve · Post by **Scooba_Steve** » Thu Feb 23, 2017 4:32 pm

But you can't swap front to rear, and if a chunkier sidewall is wanted then why not drop to 17?

streetcar · Post by **streetcar** » Thu Feb 23, 2017 10:29 pm

Hi guys thanks, All comments appreciated the more the better.
My main aim was to run 4 tyres of the same size, i never said bigger side walls was a priority I only meant that the bigger side walls that this size tyre gives would not be unwelcome, I just don't see the point of fitting two different tyre sizes.
I've never understood why BMW chose a staggered wheel set up in the first place, the benefits it gives seem a bit remote and it seems quite a few people on here run four fronts or four rears at both 18" and 19" rims with no loss of performance.
My main concern was going bigger on the front rather then reducing the rear size as I was concerned this would make the steering slow or make it feel heavy

Cheers once again
Sd

vester86 · Post by **vester86** » Fri Feb 24, 2017 1:41 am

To overcome this "issue" i mounted the (correct) 225/40/18 on front & (not correct) 235/40/18 on the back. I have. Set of style 135m wheels. (mv2) so the wheels are 8"/8,5" anyways. Closed to a sqare setup but with the different wheel width in mind

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