Are my tyres too wide?

Calps · Post by **Calps** » Thu Apr 15, 2021 10:04 pm

I'm shopping for some new rims at the moment, and it prompted me to check my current wheels so I could input into willtheyfit.com.

I've got what I believe are genuine MV2s (so 8j front & 8.5j rear) but the tyre sizes seems to be more than what's needed based on the recommendations I've seen suggested for wider rims.

Front: 8j 225/40/R18
Rear: 8.5j 255/35/R18

I've usually seen widths of 225 suggested for 8.5j rims, and 255 for 9.5j so this makes me thin they're wider than needed, especially on the rear.

It's not a huge issue as I'll be changing them soon, but curious if anyone knows any reason why they'd be this size? Are there benefits to it? Do they come from BMW like this? Or has a previous owner not realised what they were doing/fitting?

Mr Tidy · Post by **Mr Tidy** » Thu Apr 15, 2021 10:14 pm

Those are the standard sizes used by BMW on staggered 18s for the E85/86.

To be honest I quite liked them being relatively wide - it gives a bit more protection for the rims!

M1k3yC · Post by **M1k3yC** » Thu Apr 15, 2021 10:26 pm

I have genuine MV2s, tyres fitted are:

Michelin Pilot Sport 2 Zero Pressure (BMW) 225/40 R18 W (88), front
Michelin Pilot Sport 2 Zero Pressure (BMW) 255/35 R18 W (90), rear

As Mr Tidy says, standard BMW fit.

Calps · Post by **Calps** » Thu Apr 15, 2021 10:28 pm

Mr Tidy wrote: ↑Thu Apr 15, 2021 10:14 pm Those are the standard sizes used by BMW on staggered 18s for the E85/86.

To be honest I quite liked them being relatively wide - it gives a bit more protection for the rims!

That solves it then, thanks folks!

brillomaster · Post by **brillomaster** » Sat Apr 17, 2021 11:20 am

Arguably, most z4s (with the exception of maybe z4ms) do not need a 255 rear, they just dont have the torque or weight. Bmw like it because wider rear tyres are perceived as being sporty and look better. The stagger also encourages nice, safe understeer.

You'll likely find a z4 drives and rides better with more neutral handling on the road on 225s all round, like the standard 17s.

When i tracked my car, i kept the 18s with a 255 rear, but upped the fronts to 245, again for more neutral handling and that worked well for me.

Calps · Post by **Calps** » Sat Apr 17, 2021 12:16 pm

brillomaster wrote: ↑Sat Apr 17, 2021 11:20 am Arguably, most z4s (with the exception of maybe z4ms) do not need a 255 rear, they just dont have the torque or weight. Bmw like it because wider rear tyres are perceived as being sporty and look better. The stagger also encourages nice, safe understeer.

You'll likely find a z4 drives and rides better with more neutral handling on the road on 225s all round, like the standard 17s.

When i tracked my car, i kept the 18s with a 255 rear, but upped the fronts to 245, again for more neutral handling and that worked well for me.

Thanks brillomaster. I'm switching to a square 8.5j setup with 235 all round, so happy to hear that a similar setup improves the experience for you.

Z4-forum.com

Z4-forum.com