Yet Another Wheel / Tyre Question

TheDan · Post by **TheDan** » Thu Sep 22, 2022 11:44 am

Hi all,

I know we get a lot of wheel and tyre fitment questions, but I am looking for quite a specific use case and have searched and can only find a few posts with similar but not the same sizes, so I thought I'd ask.

I am going to be purchasing a set of Protrack One wheels to replace my buckled MV2s. I'm choosing Protracks because they are definitely capable of dealing with our terrible roads without buckling/cracking as they're battered around the ring by the Apex guys day in day out (brutal kerbs) and I love the look of them.

Here is my current setup:

Front: 18x8J ET47 + 12mm spacers (225/40/18)

Rear: 18x8.5J ET50 + 12mm spacers (245/35/18)

Below are the setups I am considering:

Front: 17x7.5J ET30 (235/45/17)

Rear: 17x9J ET38 (255/40/17)

.

Front: 17x9J ET38 (235/45/17)

Rear: 17x9J ET38 (255/40/17)

.

Front: 18x8J ET45 + 12mm spacers (235/40/18)

Rear: 18x9J ET50 + 12mm spacers (255/35/18)

I know that the 18s above will fit because they're very similar to my current setup. However, I would like to run 17s for the extra sidewall and lower weight.

If I were to run the 17x7.5J on the front, the setup would be "over tyred" which I am pretty sure would destroy the sidewalls on track. What are people's thoughts on this?

I have played about on willtheyfit.com to get "acceptable" offsets and tyre fitments, but what I am mainly looking for is to see if anyone here has run a 9J on the front with a 235 tyre on an E85/E86 and whether they experienced rubbing or not.

TheDan · Post by **TheDan** » Mon Sep 26, 2022 1:51 pm

I know its very specific, but anyone use similar size fronts?

Pondrew · Post by **Pondrew** » Mon Sep 26, 2022 2:06 pm

www.willtheyfit.com
Excellent tool for comparing wheel sizes, offsets etc. Gives lots of data.

TheDan · Post by **TheDan** » Mon Sep 26, 2022 2:11 pm

Pondrew wrote: ↑Mon Sep 26, 2022 2:06 pm www.willtheyfit.com
Excellent tool for comparing wheel sizes, offsets etc. Gives lots of data.

I guess you didn't read all the first post

I checked willtheyfit.com and while its a great tool for checking offsets and poke, it really doesn't have enough information for whether a tyre will rub or not as it can't generate an accurate diagram for the tyre edge/corner.

This is why I am looking for a few (if they exist lol) first hand experiences of people using 9J fronts with 225-245 tyre sizes.

Pondrew · Post by **Pondrew** » Mon Sep 26, 2022 2:32 pm

TheDan wrote: ↑Mon Sep 26, 2022 2:11 pm I guess you didn't read all the first post

Nope, obviously I didn't. Sorry.

Note to self: pay more attention Pond!

Mr Tidy · Post by **Mr Tidy** » Mon Sep 26, 2022 8:29 pm

I haven't run 9J fronts but when I got my MC it had CSL Reps on the front that were 8.5J with 235/35x19 MPSS tyres and they didn't rub at all - well not once I got rid of the spacers and got the coil-overs to a sensible ride height!

If it helps the rears were 9.5J with 265/30 x 19 tyres and they didn't rub either, although all the tyres were about half worn with 4mm of tread - new tyres would obviously be a few mm bigger.

Jellyfishfields · Post by **Jellyfishfields** » Mon Sep 26, 2022 11:19 pm

You've maybe seen this already and it's a different make, but the Apex fitment guide may offer some help with what you're looking for.
https://support.apexraceparts.com/hc/en ... ment-Guide

Good you mentioned the Protracks, I'd not heard of them but they look really good.

brillomaster · Post by **brillomaster** » Tue Sep 27, 2022 8:52 am

my standard ride height E85 3.0i ran a 245/35/R18 front tyre on a standard 8" front wheel with standard offset, that didnt have any rubbing...

TheDan · Post by **TheDan** » Wed Sep 28, 2022 12:45 pm

Jellyfishfields wrote: ↑Mon Sep 26, 2022 11:19 pm You've maybe seen this already and it's a different make, but the Apex fitment guide may offer some help with what you're looking for.
https://support.apexraceparts.com/hc/en ... ment-Guide

Good you mentioned the Protracks, I'd not heard of them but they look really good.

Thanks for this, I did reach out to them asking about their 17x9J square setup and here was the reply:

"Thank you for reaching out in regards to your non-M Z4. With the 17x9" ET30 square setup, the most ideal tire size would be 245/40-17s at all four corners. While that setup will be a complete direct fit in the rear, the front will require a bit of work to fit without rubbing. Typically, depending on your ride height and specific tire selection, around -2.0 to -2.5 degrees of front camber will be required to fit this setup."

brillomaster wrote: ↑Tue Sep 27, 2022 8:52 am my standard ride height E85 3.0i ran a 245/35/R18 front tyre on a standard 8" front wheel with standard offset, that didnt have any rubbing...

This is useful, thanks. I was slightly aware you were running a 245 on track from other posts you've made, but it gives me confidence a 235 tyre on a 9J should also be fine.

I am going to try to find someone nearby or at my next track day using a 9J (or 8.5J) with a 235 tyre to check fitment. Hopefully someone will be using this wheel/tyre combo.

Z4-forum.com

Z4-forum.com