[NGR]

My front tyres were nearing the tread wear indicators and unfortunately I had a puncture on one of them so thought I'd get a pair and try wider tyres on the standard rims - I don't know if anyone has confirmed this before but the 245/40/20 Bridgestone Potenza S001s fit fine on the front 7.5" rims They're replacing the original 215s - no rubbing, funny noises etc... I think this size is the normal for the rear on the thinner wheels?

I wanted to stick with the Potenza S001 as it's the 'chosen' compound from BMW and I think quite soft.

Initial thoughts: the steering feels noticeably heavier (which I like) and more positive - I haven't driven it far yet though. It also looks fine, the tyre sticks out a little further offering more protection for the rim, again a good thing.

I'm hoping it will reduce the TC kicking in on the front axle in the wet, I don't expect the car to stick like shit to a blanket but any improvement will be welcome Also, my old tyres had likely "gone off" as tyres often do when they're wearing down - I might be comparing apples to oranges here.

My rears are quite new but I'm tempted to go up a notch with a wider pair of those as well.

[iHyperMiler]

On the inside there is only about 12 mm space between the 215 tire and the suspension at the top. Unless you are using a 10 mm spacer your 245 is very close to touching there.

[NGR]

Originally Posted by iHyperMiler

On the inside there is only about 12 mm space between the 215 tire and the suspension at the top. Unless you are using a 10 mm spacer your 245 is very close to touching there.

Yep - it's a bit tight but I'll check the insides of the tyres after a few miles. Any sign of contact and I'll add a spacer.
So far, no weird noises but I haven't "bottomed" the suspension yet on any big bumps.

Traction definitely improved in the wet.

[MKSixer]

I run 255s in the front and 275s in the rear with no problems.

[Nachbar]

Originally Posted by MKSixer

I run 255s in the front and 275s in the rear with no problems.

On OEM Rims? Could you post some pics please?

[MKSixer]

Originally Posted by Nachbar

On OEM Rims? Could you post some pics please?

Yes. On OEM wheels with no problems, whatsoever. I can try to post some tomorrow.

Cheers-mk

[NGR]

Originally Posted by MKSixer

Yes. On OEM wheels with no problems, whatsoever. I can try to post some tomorrow.

Cheers-mk

I checked the inside of my 245s on the front, stock wheels - no signs of anything rubbing - after approx 50 miles of driving.

Just realized my rears are only 245s - for some reason I thought they were wider. I think I'll go up to 275s as well now they're a verified successful fit

[JasH]

Originally Posted by NGR

Just realized my rears are only 245s - for some reason I thought they were wider. I think I'll go up to 275s as well now they're a verified successful fit

Which tyres though, to mix with the OEM rubber on the fronts?

Interesting experiment

[NGR]

Originally Posted by JasH

Which tyres though, to mix with the OEM rubber on the fronts?

Interesting experiment

Haven't checked sizes in the Bridgestones but prefer to stick to s001 compound if available in that size...

[SteveB_UK]

Originally Posted by NGR

Haven't checked sizes in the Bridgestones but prefer to stick to s001 compound if available in that size...

There's a 275/35/20 s001 which has almost as good a wet grip rating as the BMW 245:

https://www.mytyres.co.uk/rshop/Tyre...2Y-XL/R-233092

And I will very likely be getting a pair of these soon and moving my rears to the front as my fronts are almost shot.

[JasH]

Originally Posted by SteveB_UK

There's a 275/35/20 s001 which has almost as good a wet grip rating as the BMW 245:

https://www.mytyres.co.uk/rshop/Tyre...2Y-XL/R-233092

And I will very likely be getting a pair of these soon and moving my rears to the front as my fronts are almost shot.

Looks good


But might these not be best of all? https://www.pirelli.com/tyres/en-gb/...et/p-zerocorsa

These precise ones: https://www.mytyres.co.uk/cgi-bin/rs...m_s=3&profil=P ZERO CORSA&search_tool=standard

[NGR]

Originally Posted by SteveB_UK

There's a 275/35/20 s001 which has almost as good a wet grip rating as the BMW 245:

https://www.mytyres.co.uk/rshop/Tyre...2Y-XL/R-233092

And I will very likely be getting a pair of these soon and moving my rears to the front as my fronts are almost shot.

Might give those a try.
Just playing with the 245's on the front (and on the back!) I still get understeer (with much less TC intervention).
This tells me that:
(1) I'm probably too heavy footed coming out of bends (I was trying to test the limits though
(2) Wider rears might not really make a difference?
(3) The front e-motor has plenty power/torque (at least in the corners)

Steering definitely "heavier" - I like this.

Any thought ladies and gents - anyone running wider rears getting similar feedback?

[iHyperMiler]

Originally Posted by NGR

I checked the inside of my 245s on the front, stock wheels - no signs of anything rubbing - after approx 50 miles of driving.

Just realized my rears are only 245s - for some reason I thought they were wider. I think I'll go up to 275s as well now they're a verified successful fit

Can you please take a picture of the rod that wraps around the tire on the inside, and one from the outside at the top front fender edge?

Are you running 0 camber?

[NGR]

Originally Posted by iHyperMiler

Can you please take a picture of the rod that wraps around the tire on the inside, and one from the outside at the top front fender edge?

Are you running 0 camber?

Hopefully you can see the pics - not the best but I'll try later with some proper lighting.

And, no camber change, I just got my tyre depot to put new rubber on.

[SteveB_UK]

Originally Posted by NGR

Might give those a try.
Just playing with the 245's on the front (and on the back!) I still get understeer (with much less TC intervention).
This tells me that:
(1) I'm probably too heavy footed coming out of bends (I was trying to test the limits though
(2) Wider rears might not really make a difference?
(3) The front e-motor has plenty power/torque (at least in the corners)

Steering definitely "heavier" - I like this.

Any thought ladies and gents - anyone running wider rears getting similar feedback?

Understeer might just be your driving style. Also the factory camber could probably help being altered to give some neg camber at the front but from what's posted either on this thread or elsewhere there is very little clearance so putting some new camber on may require spacers.

I'm not a fan of spacers as they change the ET and the suspension geometry will have been specced around a specific ET. And there aren't enough people (any?) racing these for there to be good reliable alternative geo information.

[SteveB_UK]

Originally Posted by JasH

Looks good


But might these not be best of all? https://www.pirelli.com/tyres/en-gb/...et/p-zerocorsa

These precise ones: https://www.mytyres.co.uk/cgi-bin/rs...m_s=3&profil=P ZERO CORSA&search_tool=standard

I like the S001s TBO for the road. Nice amount of grip for a relatively well lasting tyre and those Corsas will last about 10 minutes so not really economical on a DD! I also fear that they will be too much for front S001s and change the balance to too much understeer.

I save the sticky tyres for my Elise

[NGR]

Originally Posted by SteveB_UK

Understeer might just be your driving style. Also the factory camber could probably help being altered to give some neg camber at the front but from what's posted either on this thread or elsewhere there is very little clearance so putting some new camber on may require spacers.

I'm not a fan of spacers as they change the ET and the suspension geometry will have been specced around a specific ET. And there aren't enough people (any?) racing these for there to be good reliable alternative geo information.

I don't really want to mess around with the geometry without more info, it is pretty tight under there and looks like a different setup other cars I've looked at. I might have to pull a wheel off and have a good look at what's in there.

The under-steer is noticeably reduced though and I only really get it if I provoke the car by accelerating too early through the bends. Cold, bumpy UK roads probably don't help either!

[SteveB_UK]

Originally Posted by NGR

I don't really want to mess around with the geometry without more info, it is pretty tight under there and looks like a different setup other cars I've looked at. I might have to pull a wheel off and have a good look at what's in there.

The under-steer is noticeably reduced though and I only really get it if I provoke the car by accelerating too early through the bends. Cold, bumpy UK roads probably don't help either!

Four wheel drive cars tend to understeer in general if pushed, unless you provoke them to oversteer - Scandinavian Flick!!

[iHyperMiler]

Thank you, great work!

I had been wondering specifically about the distance to the steering knuckle, i. e. the suspension rod ending above the tire. It clears the tire by about 15mm, so exactly the width you add on the inside when you go 30 mm wider from 215 to 245.




RE camber: There is a BMW -30 min top wishbone for these front axles (5 series etc) that will add a half a degree of negative camber (and should be within factory spec.).

[NGR]

Originally Posted by iHyperMiler

Thank you, great work!

I had been wondering specifically about the distance to the steering knuckle, i. e. the suspension rod ending above the tire. It clears the tire by about 15mm, so exactly the width you add on the inside when you go 30 mm wider from 215 to 245.




RE camber: There is a BMW -30 min top wishbone for these front axles (5 series etc) that will add a half a degree of negative camber (and should be within factory spec.).

Whoahhh, great picture!

The clearance you're talking about I checked the other day when I had the tyres fitted and I can get my finger in between it and the tyre (as far as my hand will go anyway!) That's even with the wider 245 tyres on (which are a touch taller than the standard 215s as well).

The suspension does look quite futuristic down there, the knuckle presumably moves with the wheel otherwise there would be contact.

[JasH]

Originally Posted by SteveB_UK

I like the S001s TBO for the road. Nice amount of grip for a relatively well lasting tyre and those Corsas will last about 10 minutes so not really economical on a DD! I also fear that they will be too much for front S001s and change the balance to too much understeer.

I save the sticky tyres for my Elise

Agree that if you did use the Corsa's they would definitely need to go on all 4 wheels. And would be uneconomical on a DD.

[iHyperMiler]

Yes the knuckle in fact carries the hub and turns with the wheel. It allows to direct the steering rotation much closer down the middle of the wheel.

Trying to figure out why my 215 is exactly as close as you describe. A half inch more would definitely touch the knuckle.