Tyre Size Recommendation for 8.5 x 18 Rims - E86 Coupe

Alloy wheels and tyre discussion
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rally-chris
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Tyre Size Recommendation for 8.5 x 18 Rims - E86 Coupe

Post by rally-chris » Wed Sep 13, 2017 10:53 am

Hi,

Please could you give me some advice on what sensible tyre size to run on a square set 8.5 x 18 ET35 rims on an 08 E86 Coupe (std Sport suspension)? I'm looking at getting a used set of Team Dynamics Le Mans rims for daily use, whilst I get my 108s refurbished and kept for summer/show use.

The new wheels are the same width as standard rears, albeit set 15mm further out (ET35 vs ET50), so will I be OK with standard tyre size, i.e. 255/35 18?

The fronts will be wider than standard (8") and by my calcs the outside of the rim will be nearly 25mm further out (ET35 vs ET47 + extra 12.7mm width), so will I need to be careful about tyre size? Will I get away with the standard size of 225/40 18 or will this look stupid on the wider rim anyway? I'm not a fan of the stretched look and I would prefer some tyre to protect the rim, so what else would fit?

Many Thanks!

Chris
08 Z4 3.0si Sport Coupe in Montego Blue

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jamie_z4
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Tyre Size Recommendation for 8.5 x 18 Rims - E86 Coupe

Post by jamie_z4 » Wed Sep 13, 2017 10:58 am

rally-chris wrote:
Wed Sep 13, 2017 10:53 am
Hi,

Please could you give me some advice on what sensible tyre size to run on a square set 8.5 x 18 ET35 rims on an 08 E86 Coupe (std Sport suspension)? I'm looking at getting a used set of Team Dynamics Le Mans rims for daily use, whilst I get my 108s refurbished and kept for summer/show use.

The new wheels are the same width as standard rears, albeit set 15mm further out (ET35 vs ET50), so will I be OK with standard tyre size, i.e. 255/35 18?

The fronts will be wider than standard (8") and by my calcs the outside of the rim will be nearly 25mm further out (ET35 vs ET47 + extra 12.7mm width), so will I need to be careful about tyre size? Will I get away with the standard size of 225/40 18 or will this look stupid on the wider rim anyway? I'm not a fan of the stretched look and I would prefer some tyre to protect the rim, so what else would fit?

Many Thanks!

Chris
hi Chris, a 225 isnt daft at all, ive run 225 40 on an 8.5 and its barely any stretch if anything, i think a 255 35 is 'over tyred' for a 8.5j rim, for example, the m135i (with all that power) runs a 245/35 on a 8.5j rear wheel out of the box, so with a 225/40 front and 255/35/18 you'll be fine and not encounter any rubbing , presuming your at std height?
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rally-chris
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Tyre Size Recommendation for 8.5 x 18 Rims - E86 Coupe

Post by rally-chris » Wed Sep 13, 2017 11:09 am

jamie_z4 wrote:
Wed Sep 13, 2017 10:58 am
rally-chris wrote:
Wed Sep 13, 2017 10:53 am
Hi,

Please could you give me some advice on what sensible tyre size to run on a square set 8.5 x 18 ET35 rims on an 08 E86 Coupe (std Sport suspension)? I'm looking at getting a used set of Team Dynamics Le Mans rims for daily use, whilst I get my 108s refurbished and kept for summer/show use.

The new wheels are the same width as standard rears, albeit set 15mm further out (ET35 vs ET50), so will I be OK with standard tyre size, i.e. 255/35 18?

The fronts will be wider than standard (8") and by my calcs the outside of the rim will be nearly 25mm further out (ET35 vs ET47 + extra 12.7mm width), so will I need to be careful about tyre size? Will I get away with the standard size of 225/40 18 or will this look stupid on the wider rim anyway? I'm not a fan of the stretched look and I would prefer some tyre to protect the rim, so what else would fit?

Many Thanks!

Chris
hi Chris, a 225 isnt daft at all, ive run 225 40 on an 8.5 and its barely any stretch if anything, i think a 255 35 is 'over tyred' for a 8.5j rim, for example, the m135i (with all that power) runs a 245/35 on a 8.5j rear wheel out of the box, so with a 225/40 front and 255/35/18 you'll be fine and not encounter any rubbing , presuming your at std height?
Thanks Jamie - yes, I'm on standard (Sport) ride height and no plans to lower it (or else I might not get out of my driveway!).
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patriot66
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Tyre Size Recommendation for 8.5 x 18 Rims - E86 Coupe

Post by patriot66 » Wed Sep 13, 2017 6:26 pm

My Zed's a roadster with Sport springs fitted and I'm running 255/35 18 rear and 225/40 18 front mounted on MV3s, rear ET37 and front ET34. The rears are absolutely fine and never catch or rub. The fronts catch slightly on the top leading outer edge of wheel arch liner but ONLY when the car goes into some high speed compression bumps, no other time. :thumbsup:
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1doohan
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Tyre Size Recommendation for 8.5 x 18 Rims - E86 Coupe

Post by 1doohan » Sat Oct 21, 2017 12:34 pm

Running 255/40 18 on rear
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Buckz
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Tyre Size Recommendation for 8.5 x 18 Rims - E86 Coupe

Post by Buckz » Sat Oct 21, 2017 12:38 pm

patriot66 wrote:
Wed Sep 13, 2017 6:26 pm
My Zed's a roadster with Sport springs fitted and I'm running 255/35 18 rear and 225/40 18 front mounted on MV3s, rear ET37 and front ET34. The rears are absolutely fine and never catch or rub. The fronts catch slightly on the top leading outer edge of wheel arch liner but ONLY when the car goes into some high speed compression bumps, no other time. :thumbsup:
I'm running et30 8.5 with 225 on front on my other set and the exact same thing, catches a tiny bit on high speed bumps but 99% of driving it doesn't rub at all.
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rally-chris
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Tyre Size Recommendation for 8.5 x 18 Rims - E86 Coupe

Post by rally-chris » Sat Oct 21, 2017 5:55 pm

Follow up to the OP - I went with standard Z sizes on the 8.5” ET35 Le Mans rims and all seems well so far.
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08 Z4 3.0si Sport Coupe in Montego Blue

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