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A question for the wheel/tyre gurus........

Alloy wheels and tyre discussion
Z43.0Si
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A question for the wheel/tyre gurus........

Post by Z43.0Si » Mon May 15, 2017 12:32 pm

I'm about to purchase some Michelin PS4s's for my e86 which is running 19" wheels.

My choice for the front is a 235/35/19 but I'm struggling to decide between a 255/35/19 or a 265/30/19 for the rear.

The wheels are 8.5j at the front and 9.5j at the rear.

Your thoughts and advice please.

Thanks in advance

Z43.0Si

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vester86
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A question for the wheel/tyre gurus........

Post by vester86 » Mon May 15, 2017 3:06 pm

i would say 255 for the rear to keep understeer minimum. perfect fit on the 9,5 rim also and the 35 sidewall gives a little more comfort then the 265/30

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A question for the wheel/tyre gurus........

Post by mr wilks » Mon May 15, 2017 5:50 pm

Id agree with the above 100% , i always run 255 35 19 rears on 9j or 9.5j widths as opposed to 265 30
Fronts i would be wary of 235 35 on your 8.5j if the offset is low & the ride height is also non standard .
You may be getting away with it at the mo with worn tyres on 3mm but throw some 8mm tread on & you may find they catch at times :?
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A question for the wheel/tyre gurus........

Post by Z43.0Si » Mon May 15, 2017 9:11 pm

mr wilks wrote: Mon May 15, 2017 5:50 pm Id agree with the above 100% , i always run 255 35 19 rears on 9j or 9.5j widths as opposed to 265 30
Fronts i would be wary of 235 35 on your 8.5j if the offset is low & the ride height is also non standard .
You may be getting away with it at the mo with worn tyres on 3mm but throw some 8mm tread on & you may find they catch at times :?

Thank you for the gen mr Wilks.

I'm currently running a 225/35/19 on the front and a 255/30/19 on the rear.
I'm trying to loose the stretch on the front hence considering going up to a 235.

I'm still running the standard m-sport suspension currently but with track use in mind there may be a suspension upgrade in the future.

What would you recommend?

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mr wilks
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A question for the wheel/tyre gurus........

Post by mr wilks » Mon May 15, 2017 9:39 pm

Z43.0Si wrote: Mon May 15, 2017 9:11 pm
mr wilks wrote: Mon May 15, 2017 5:50 pm Id agree with the above 100% , i always run 255 35 19 rears on 9j or 9.5j widths as opposed to 265 30
Fronts i would be wary of 235 35 on your 8.5j if the offset is low & the ride height is also non standard .
You may be getting away with it at the mo with worn tyres on 3mm but throw some 8mm tread on & you may find they catch at times :?

Thank you for the gen mr Wilks.

I'm currently running a 225/35/19 on the front and a 255/30/19 on the rear.
I'm trying to loose the stretch on the front hence considering going up to a 235.

I'm still running the standard m-sport suspension currently but with track use in mind there may be a suspension upgrade in the future.

What would you recommend?
What offset ?
3 ZMRs
3 E89s
5 Si coupes
5 Si roadsters
997 C4
TTRS
F82 M4
MK7 Golf Gti
current Bmw 6 Gran Turismo

Z43.0Si
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A question for the wheel/tyre gurus........

Post by Z43.0Si » Mon May 15, 2017 11:40 pm

mr wilks wrote: Mon May 15, 2017 9:39 pm
Z43.0Si wrote: Mon May 15, 2017 9:11 pm
mr wilks wrote: Mon May 15, 2017 5:50 pm Id agree with the above 100% , i always run 255 35 19 rears on 9j or 9.5j widths as opposed to 265 30
Fronts i would be wary of 235 35 on your 8.5j if the offset is low & the ride height is also non standard .
You may be getting away with it at the mo with worn tyres on 3mm but throw some 8mm tread on & you may find they catch at times :?

Thank you for the gen mr Wilks.

I'm currently running a 225/35/19 on the front and a 255/30/19 on the rear.
I'm trying to loose the stretch on the front hence considering going up to a 235.

I'm still running the standard m-sport suspension currently but with track use in mind there may be a suspension upgrade in the future.

What would you recommend?
What offset ?
I have no idea sadly. I guess I will have to remove the wheels in the hope the ET is marked on them.

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A question for the wheel/tyre gurus........

Post by bmwaddict » Mon May 15, 2017 11:52 pm

If not you can measure the offset mate, some guides online. Not easy all this, I'm struggling with my own wheel/tyre conundrum.
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Z43.0Si
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A question for the wheel/tyre gurus........

Post by Z43.0Si » Tue May 16, 2017 9:55 pm

mr wilks wrote: Mon May 15, 2017 9:39 pm
Z43.0Si wrote: Mon May 15, 2017 9:11 pm
mr wilks wrote: Mon May 15, 2017 5:50 pm Id agree with the above 100% , i always run 255 35 19 rears on 9j or 9.5j widths as opposed to 265 30
Fronts i would be wary of 235 35 on your 8.5j if the offset is low & the ride height is also non standard .
You may be getting away with it at the mo with worn tyres on 3mm but throw some 8mm tread on & you may find they catch at times :?

Thank you for the gen mr Wilks.

I'm currently running a 225/35/19 on the front and a 255/30/19 on the rear.
I'm trying to loose the stretch on the front hence considering going up to a 235.

I'm still running the standard m-sport suspension currently but with track use in mind there may be a suspension upgrade in the future.

What would you recommend?
What offset ?
I managed to get the offsets today. Front 38, Rear 40

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mr wilks
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A question for the wheel/tyre gurus........

Post by mr wilks » Tue May 16, 2017 10:15 pm

235 35 19 on 8.5j et 38 on a E86 is most likely going to rub on compression in the bends when cracking on , normal roads following the speed limits you may be ok / its a very fine line you are treading but expensive if you have to change the new tyres again :cry: what tyres are you on at the mo ? A 225 35 in a different brand may not look as stretched :? or as i did with my Stratus grey Si roady
a 225 40 19 on the front ? Slightly round the shoulders with a little more height , not ideal though if you plan to drop

standard springs

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3 ZMRs
3 E89s
5 Si coupes
5 Si roadsters
997 C4
TTRS
F82 M4
MK7 Golf Gti
current Bmw 6 Gran Turismo

Z43.0Si
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A question for the wheel/tyre gurus........

Post by Z43.0Si » Tue May 16, 2017 10:43 pm

mr wilks wrote: Tue May 16, 2017 10:15 pm 235 35 19 on 8.5j et 38 on a E86 is most likely going to rub on compression in the bends when cracking on , normal roads following the speed limits you may be ok / its a very fine line you are treading but expensive if you have to change the new tyres again :cry: what tyres are you on at the mo ? A 225 35 in a different brand may not look as stretched :? or as i did with my Stratus grey Si roady
a 225 40 19 on the front ? Slightly round the shoulders with a little more height , not ideal though if you plan to drop

standard springs

Image
I'm currently running continentals, conti sport 5s I believe if my memory serves me correctly. As I mentioned, I'm looking to order some Michelin pilot sport 4s's.

I drive the car hard on track at times so I've got to get this right! I appreciate all your help :thumbsup:

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A question for the wheel/tyre gurus........

Post by z4pilot » Wed May 17, 2017 10:16 am

mr wilks wrote: Tue May 16, 2017 10:15 pm 235 35 19 on 8.5j et 38 on a E86 is most likely going to rub on compression in the bends when cracking on , normal roads following the speed limits you may be ok / its a very fine line you are treading but expensive if you have to change the new tyres again :cry: what tyres are you on at the mo ? A 225 35 in a different brand may not look as stretched :? or as i did with my Stratus grey Si roady
a 225 40 19 on the front ? Slightly round the shoulders with a little more height , not ideal though if you plan to drop

standard springs

Image
My experience mirrors the advice here. 19 inch 8.5 width with ET38, on Eibach springs and standard M-Sport shocks rubbed frequently with 235's, which forced me to drop to 225 width Uniroyal Rainsports. This reduced the rubbing by 90%, but it would still rub with full compression of the suspension on spirited drives. In the end it spoiled the experience for me and I swopped back to 18's with slightly more conservative offsets...
Now Gone - 2008 Coupe, Montego Blue, Champagne leather and Piano Black interior, Eibachs & Koni Sport shocks, Style 230 19s, Eisenmann Quad - approaching perfection...

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A question for the wheel/tyre gurus........

Post by Z43.0Si » Wed May 17, 2017 12:01 pm

It's good to get some personal experience feedback for this, so thanks for that.

Looking at the amount of stretch I currently have on a 225 I'm amazed at just going to a 235 caused so much issues, it just doesn't look right with a 225 fitted. I'm really at a loss now as to what to do???

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A question for the wheel/tyre gurus........

Post by vester86 » Thu May 18, 2017 8:59 am

tyre stretch is fairly different with different brand&types of tyres. michelin PS4 looks slightly stretched on my car (225/40/18 on a 8J rim)
only thing to solve this is to look for another set of wheels (with an higher offset OR a smaller wheel ( 8J in stead of 8.5J for example).

some wheels you can machine a couple mm so you change the offset.

notting wrong with a small amount of tyre stretch though, gives more feeling with the road, less vague handling

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A question for the wheel/tyre gurus........

Post by STUBOY2UK » Thu May 18, 2017 1:14 pm

I have ET38 8.5j on the front (lowered on eibach). I initially fitted 225s and didn't like the stretch. Now on 235s and it only catches when going over speedhumps to quickly etc, never noticed it catch at all when cornering.
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A question for the wheel/tyre gurus........

Post by Z43.0Si » Thu May 18, 2017 3:31 pm

STUBOY2UK wrote: Thu May 18, 2017 1:14 pm I have ET38 8.5j on the front (lowered on eibach). I initially fitted 225s and didn't like the stretch. Now on 235s and it only catches when going over speedhumps to quickly etc, never noticed it catch at all when cornering.
This is good news for me as I'm still running the standard m-sport suspension.

Decision time for me then! Put up with the 225's or go for the 235's.......?

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