Bigger wheels ??

[highway1]

I have a 2007 Coupe on 17 inch wheels as it's an SE spec. Since purchase I have refreshed and slightly upgraded the suspension with Suplex springs front and rear ( m-sport equivalent this time) and Bilstein B4 all round, as well as Poly bushes on front and rear anti-roll bars and a proper performance alignment .
This has made the car much more dynamic and planted when driving (alignment probably made most difference).

For looks, I am thinking about new wheels and fitting 18 inch.

What concerns me is I know dynamically it will be a downgrade in some respects as- slightly slower acceleration, turn in maybe not as good and what worries me the most is that it will just feel heavier and not as alive and responsive. ( probably why when the Coupe was new, BMW supplied mainly 17 inch wheel cars to the motoring press for testing, here and overseas).

I know when I changed to wider tyres (not bigger wheels) on a pickup I used to own it was noticeably less lively. (obviously much less power).

I would like to hear from people who have changed from 17 to 18 inch wheels ( and wider tyres on back as well) and there experience of this "mod" . If its only a slightly heavier feel to the car, I can probably live with that but any more and I think i'll stick with the 17's!

 

[Ducklakeview]

18"s were optional, and suit the car well. There will be no difference to acceleration and turn in will be quicker due to the lower profile rubber.

The factory 18"s were also staggered, wider wheels and tyres at the rear, and with differing offsets, this gives a wider rear track I believe.

Mike

 

[cj10jeeper]

18"s were optional, and suit the car well. There will be no difference to acceleration and turn in will be quicker due to the lower profile rubber.

The factory 18"s were also staggered, wider wheels and tyres at the rear, and with differing offsets, this gives a wider rear track I believe.

Mike

Not quite right Mike as although the rolling radius will be similar for 18's given they have a lower profile tyre the rotating mass will be further from the centre of the rim and thus will have a detrimental effect on acceleration steering and braking. Will it be noticeable - highly unlikely given the power of the engine and small increase in size

I'd agree re the point that the lower profile tyres will improve the turn is with less side wall flex

 

[patriot66]

My Zed is a 2003 SE and had the standard 17" 103 alloys with diabolical Bridgestone RFTs all round when I bought it. I changed to a staggered set of 18" MV3s with non-RFTs, 225/40 front and 255/ 35 rear. At the same time I fitted Sport springs and had a full Hunter 4 wheel alignment carried out.
The improvement in all aspects of handling, dynamism and ride quality was enormous. The looks and stance of the car are also vastly improved. I have no regrets whatsoever in changing to 18" wheels and would thoroughly recommend it !

 

[cj10jeeper]

My Zed is a 2003 SE and had the standard 17" 103 alloys with diabolical Bridgestone RFTs all round when I bought it. I changed to a staggered set of 18" MV3s with non-RFTs, 225/40 front and 255/ 35 rear. At the same time I fitted Sport springs and had a full Hunter 4 wheel alignment carried out.
The improvement in all aspects of handling, dynamism and ride quality was enormous. The looks and stance of the car are also vastly improved. I have no regrets whatsoever in changing to 18" wheels and would thoroughly recommend it !

This is all so true. Removing RFT's changing springs and alignment are all real great changes. Looks without doubt improve too and would be reason enough for me to ditch 17's

 

[coaldust]

interesting thread, ive just fitted a set of gunmetal 19in cades tyrus, and eibach pro kit, i had 108's before, i know the purists say stick with 108's 107's etc but there really is no comparison, i was a bit nervous getting them fitted cos i was worried how they would look, but wow, i will tell you something, when viewing pics etc of z4's on deep dish rims etc the pic does no justice, you have to see the car on the wheels irl to get the real effect.

drop the hood now and im getting attention prolly not far off of a ferrari, maybe a bit to many looks lol, ill put some pics up soon

forgot to add they 19x8.5 19x9.5 staggered so you got that 4in polished lip. do have some front rubbing issues over speed bumbs etc but nothing that aint gonna be sorted with the old dremmel, and ride quality is firm but like its on rails, so cant understand why ppl say avoid 19in, they fill the arch proper.

 

[bobo075]

It will be better with 18" wheels without runflat...
but I am surprise that you put some Biltein B4 on your car... specialy with shorter springs, B6 would have been much better and efficient...

 

[mr wilks]

interesting thread, ive just fitted a set of gunmetal 19in cades tyrus, and eibach pro kit, i had 108's before, i know the purists say stick with 108's 107's etc but there really is no comparison, i was a bit nervous getting them fitted cos i was worried how they would look, but wow, i will tell you something, when viewing pics etc of z4's on deep dish rims etc the pic does no justice, you have to see the car on the wheels irl to get the real effect.

drop the hood now and im getting attention prolly not far off of a ferrari, maybe a bit to many looks lol, ill put some pics up soon

forgot to add they 19x8.5 19x9.5 staggered so you got that 4in polished lip. do have some front rubbing issues over speed bumbs etc but nothing that aint gonna be sorted with the old dremmel, and ride quality is firm but like its on rails, so cant understand why ppl say avoid 19in, they fill the arch proper.

What et fronts & what size tyres ? Can probably be sorted without drastic Dremmel action

 

[kis]

interesting thread, ive just fitted a set of gunmetal 19in cades tyrus, and eibach pro kit, i had 108's before, i know the purists say stick with 108's 107's etc but there really is no comparison, i was a bit nervous getting them fitted cos i was worried how they would look, but wow, i will tell you something, when viewing pics etc of z4's on deep dish rims etc the pic does no justice, you have to see the car on the wheels irl to get the real effect.

drop the hood now and im getting attention prolly not far off of a ferrari, maybe a bit to many looks lol, ill put some pics up soon

forgot to add they 19x8.5 19x9.5 staggered so you got that 4in polished lip. do have some front rubbing issues over speed bumbs etc but nothing that aint gonna be sorted with the old dremmel, and ride quality is firm but like its on rails, so cant understand why ppl say avoid 19in, they fill the arch proper.

Let's see em

 

[highway1]

My Zed is a 2003 SE and had the standard 17" 103 alloys with diabolical Bridgestone RFTs all round when I bought it. I changed to a staggered set of 18" MV3s with non-RFTs, 225/40 front and 255/ 35 rear. At the same time I fitted Sport springs and had a full Hunter 4 wheel alignment carried out.
The improvement in all aspects of handling, dynamism and ride quality was enormous. The looks and stance of the car are also vastly improved. I have no regrets whatsoever in changing to 18" wheels and would thoroughly recommend it !

How much extra insurance do you have to pay, on average, for new alloys/increase in size?

Its not as if I am going up to 19" so in fact just going from SE spec to sport!

 

[patriot66]

No extra charge as the wheels are BMW OEM and were a factory option in the sizes I have. Likewise for the tyres as they are factory recommended sizes and non-RFTs all round and not a mixture.

 

[cj10jeeper]

Regardless, wheel or tyre changes have to be declared to your insurer. Even if you fit same size as a factory option then they are a change to how the car was delivered from the factory.
It affects many things from value to not least the perception that the car may be driven differently, or more desirable to steal. Just the same as sideskirts, diffusers, bumper covers , etc. All which can be factory options or aftermarket.

 

[GBZ4]

I think different insurance companies have different policies (pardon the pun) when it comes to how they handle changes such as wheels etc.

I've just taken delivery of a 440i M Sport with M Performnce goodies with 20" rollers. As all bits are identified on purchase contract the insurance company accepted as delivered. Can't quite figure at the moment I got a £25 refund for the 335d Xdrive


BTW I've stayed on 17" wheels on my Z roadster

 

[patriot66]

No extra charge as the wheels are BMW OEM and were a factory option in the sizes I have. Likewise for the tyres as they are factory recommended sizes and non-RFTs all round and not a mixture.

This is what Axa told me when I informed them of my changes.