Help! Which tyres for 8.5 front wheel?

[inkey$]

After looking more online across various other forums etc, I think for a 8.5 front wheel the 235/40/18 looks and feels like it could be the correct setup to ensure fit and aesthetics.

If anyone else is reading this and runs a non-M car with 8.5 front wheels can you help or post pictures of your setup please?

Many thanks.

[Haggisman]

After looking more online across various other forums etc, I think for a 8.5 front wheel the 235/40/18 looks and feels like it could be the correct setup to ensure fit and aesthetics.

If anyone else is reading this and runs a non-M car with 8.5 front wheels can you help or post pictures of your setup please?

Many thanks.

Hi Inkey$ More photos of my front 225 x 40 x 18 et 38. The 235 x 40 just rubbed where the blue tape was in previous photo. The et40 on your wheels may give enough clearance as they are 2 mm further in. Some extra camber could help if there is any rubbing.. My car is at standard non M suspension height
The 235 ‘S look better but didn’t work for me as I’m about to lower my car 30mm on Eibachs. I believe the PS4 tyres have quite square shoulders which don’t help.
I would say the 225’s are a safe bet but fortune favours the brave. Be good to see what you do. Cheers

[Pbondar]

Just ordered a pair of 255/35/18’s for the fronts, so will be running square wheels and tyres front and rear with the new setup

That's a lot of tyre for the front of an E85?

Clearances work out and its minimal speed and arch gap change, so should be fine.
(And its an E86)

Hello..my comment was in part addressed to the handling side of those changes..

225 to 255 is regarded as a big change for the steering to cope with..just pondered how this would affect steering and handling in the broader sense?

I know early Porksters had square set ups on those sizes but they always seemed to have their steering and handling better sorted?

[inkey$]

That's a lot of tyre for the front of an E85?

Clearances work out and its minimal speed and arch gap change, so should be fine.
(And its an E86)

Hello..my comment was in part addressed to the handling side of those changes..

225 to 255 is regarded as a big change for the steering to cope with..just pondered how this would affect steering and handling in the broader sense?

I know early Porksters had square set ups on those sizes but they always seemed to have their steering and handling better sorted?

Yes, sincere apologies Pbondar. My humour (or lack thereof) doesn’t always come across in forum posts.
After your post it got me thinking so thanks. Cancelled the 255’s as the clearance and handling issues started to worry me at those sizes. At the moment I think I’m leaning towards 235/40/18.

[brillomaster]

if you're only going up by 10mm of width, surely you might as well at least try the 225/40 tyres you already have? then you can check the level of stretch and clearance, and then decide if you do want to go wider after all.

actually, i'm running a 225/40 GY on an 8.5" rim right now on my e90, and you might think it ok... the rim protector still protrudes 5mm out from the rim itself.

EDIT if Haggisman is getting rubbing with a 235/40 and his wheels are only 2mm different to yours, i wouldn't risk a 235/40 personally.

[enuff_zed]

I guess the other question is why have you gone up to 8.5 on the front?
Can you not get 8" in that style?

[Haggisman]

if you're only going up by 10mm of width, surely you might as well at least try the 225/40 tyres you already have? then you can check the level of stretch and clearance, and then decide if you do want to go wider after all.

actually, i'm running a 225/40 GY on an 8.5" rim right now on my e90, and you might think it ok... the rim protector still protrudes 5mm out from the rim itself.

EDIT if Haggisman is getting rubbing with a 235/40 and his wheels are only 2mm different to yours, i wouldn't risk a 235/40 personally.

I’m with you on the 225’s. Tried and tested

[Pbondar]

Clearances work out and its minimal speed and arch gap change, so should be fine.
(And its an E86)

Hello..my comment was in part addressed to the handling side of those changes..

225 to 255 is regarded as a big change for the steering to cope with..just pondered how this would affect steering and handling in the broader sense?

I know early Porksters had square set ups on those sizes but they always seemed to have their steering and handling better sorted?

Yes, sincere apologies Pbondar. My humour (or lack thereof) doesn’t always come across in forum posts.
After your post it got me thinking so thanks. Cancelled the 255’s as the clearance and handling issues started to worry me at those sizes. At the moment I think I’m leaning towards 235/40/18.

No apology needed..

I spent alot of time on my E89 on handling related matters so just aware that some even small changes can make a big impact..

FWIW the E89 uses 225 and 255..I'm running 235 and 265 but that's as big as I would want to go.

[inkey$]

I guess the other question is why have you gone up to 8.5 on the front?
Can you not get 8" in that style?

Correct. 8.5 was the minimum.

[inkey$]

if you're only going up by 10mm of width, surely you might as well at least try the 225/40 tyres you already have? then you can check the level of stretch and clearance, and then decide if you do want to go wider after all.

actually, i'm running a 225/40 GY on an 8.5" rim right now on my e90, and you might think it ok... the rim protector still protrudes 5mm out from the rim itself.

EDIT if Haggisman is getting rubbing with a 235/40 and his wheels are only 2mm different to yours, i wouldn't risk a 235/40 personally.

True and maybe thats the way forward. Try the 225s I have and see what it looks and feels like first. From what Ive been reading, Goodyears are one of the more forgiving tyres.

[sars]

That's a lot of tyre for the front of an E85?

Clearances work out and its minimal speed and arch gap change, so should be fine.
(And its an E86)

Hello..my comment was in part addressed to the handling side of those changes..

225 to 255 is regarded as a big change for the steering to cope with..just pondered how this would affect steering and handling in the broader sense?

I know early Porksters had square set ups on those sizes but they always seemed to have their steering and handling better sorted?

That’s the thing, if you keep the standard set up off 225 front and 255 rear the car will tend towards an understeer characteristic (based on the zed’s 50/50 mass balance), increasing the front tyre width will obviously increase grip and thus pushes the car towards an oversteer characteristic. Also increasing front tyre width will also increase the stress on all the steering components, joints and arms. The G29 M40i setup for winter tyres is a square of 255 as I’ve just found out

[Pbondar]

Clearances work out and its minimal speed and arch gap change, so should be fine.
(And its an E86)

Hello..my comment was in part addressed to the handling side of those changes..

225 to 255 is regarded as a big change for the steering to cope with..just pondered how this would affect steering and handling in the broader sense?

I know early Porksters had square set ups on those sizes but they always seemed to have their steering and handling better sorted?

That’s the thing, if you keep the standard set up off 225 front and 255 rear the car will tend towards an understeer characteristic (based on the zed’s 50/50 mass balance), increasing the front tyre width will obviously increase grip and thus pushes the car towards an oversteer characteristic. Also increasing front tyre width will also increase the stress on all the steering components, joints and arms. The G29 M40i setup for winter tyres is a square of 255 as I’ve just found out

Hi Sars..cars seem to get bigger n bigger rim diameters and widths over time it seems..

The G29 steps up its sizes over the E89.

When you factor various sizes and wheels sizes it gets all interesting..these two videos from Tyre Reviews are really interesting to (to me )

https://www.youtube.com/watch?v=mPyg3ilw3KU

https://www.youtube.com/watch?v=Bgz0qF3CuNA

[sars]

Hello..my comment was in part addressed to the handling side of those changes..

225 to 255 is regarded as a big change for the steering to cope with..just pondered how this would affect steering and handling in the broader sense?

I know early Porksters had square set ups on those sizes but they always seemed to have their steering and handling better sorted?

That’s the thing, if you keep the standard set up off 225 front and 255 rear the car will tend towards an understeer characteristic (based on the zed’s 50/50 mass balance), increasing the front tyre width will obviously increase grip and thus pushes the car towards an oversteer characteristic. Also increasing front tyre width will also increase the stress on all the steering components, joints and arms. The G29 M40i setup for winter tyres is a square of 255 as I’ve just found out

Hi Sars..cars seem to get bigger n bigger rim diameters and widths over time it seems..

The G29 steps up its sizes over the E89.

When you factor various sizes and wheels sizes it gets all interesting..these two videos from Tyre Reviews are really interesting to (to me )

https://www.youtube.com/watch?v=mPyg3ilw3KU

https://www.youtube.com/watch?v=Bgz0qF3CuNA

Tyre Reviews is a great place for anything tyre related and knowledge, the recent one with OEM PS4S was a real eye opener. I’m of the opinion that the tyre width increase over the e89 is purely cosmetic and nothing much to do with how much grip the car needs, however more rubber in contact with the road is better excepting if it’s very wet or on snow and of course higher noise?

[Pbondar]

Sars, yes I was suprised both at the lengths that Michelin/BMW had gone to on that tyre plus the real world effects..

Fortunately for me (E89)..I won't be troubled with that choice as I can't see anyone making an E89 version..and the Potenza is now very very long in the tooth...

As I said, for me, with the mods I made, for summer 235/40 18 on 8.8j and 265/35 18 on 9.5j works very well..I tried recommended factory pressures but found for Scottish use, the rears especially, were over inflated.

Enjoy the new M40i when it arrives..will be interesting to see what you think of it compared to other cars..

[inkey$]

Right. An update…

Took my 4 x 8.5 wheels to my local trusted tyre fitter and asked for the 225/40/18 fronts and 255/35/18 rears to be swapped over from my staggered MV2s.

They did it and it looks perfect! I’m so pleased. No clearance, speed or handling issues - the Goodyear Eagle F1’s even stretched 0.5 of an inch still provide a slight amount of rim protection and it only cost me £60 to switch over. With the new front ET40 and rear ET33 they also fill out to the arches perfectly.

Very happy indeed and thanks to you all for the advice and help on this thread

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