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Changing tire profile
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- Newbie
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Changing tire profile
Hi all,
I have a Z4M Roady, and need to change the tires. The stock sizes are RIDICULOUSLY expensive (255/40/18 and 225/45/18), and the sales dude suggested that I go to 255/35/18 and 225/40/18. The price difference is about 60%.
I understand that the speedometer will over read by about 4%. The diameter difference is about 4% smaller too.
Will there be any other adverse effects (other than the speed overread)?
Thanks!
I have a Z4M Roady, and need to change the tires. The stock sizes are RIDICULOUSLY expensive (255/40/18 and 225/45/18), and the sales dude suggested that I go to 255/35/18 and 225/40/18. The price difference is about 60%.
I understand that the speedometer will over read by about 4%. The diameter difference is about 4% smaller too.
Will there be any other adverse effects (other than the speed overread)?
Thanks!
- M@r]{
- Senior Member
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- Location: East Midlands
Re: Changing tire profile
It'll handle better, slightly harsher ride, you'll have a larger gap in the arches (excuse to buy some Eibach lowering springs) and accelerate better
If it were me I'd do it
If it were me I'd do it
2006 Lotus Exige S
2006 E61 535d M-Sport Touring
2006 E61 535d M-Sport Touring
- M@r]{
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Re: Changing tire profile
BTW I'm no expert so wait for other advice before taking the plunge, thats just my take on it and what I'd do
2006 Lotus Exige S
2006 E61 535d M-Sport Touring
2006 E61 535d M-Sport Touring
- ga41
- Senior Member
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Re: Changing tire profile
I wouldn't, partly because I think my speedometer is already not that accurate but mainly because I think it would make the tires look too skinny in the wheel arches. If it was a track set of wheel/tires then I wouldn't care but not for a daily driver.
The pictures below work?
The pictures below work?
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- geepee
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Re: Changing tire profile
I thought that these are the stock sizes?BDO wrote:the sales dude suggested that I go to 255/35/18 and 225/40/18.
Thats what mine are anyway.
- ga41
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Re: Changing tire profile
Stocks are 225/45/18 and 255/40/18geepee wrote:I thought that these are the stock sizes?BDO wrote:the sales dude suggested that I go to 255/35/18 and 225/40/18.
Thats what mine are anyway.
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- Lifer
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Re: Changing tire profile
So did Igeepee wrote:I thought that these are the stock sizes?BDO wrote:the sales dude suggested that I go to 255/35/18 and 225/40/18.
Thats what mine are anyway.
- WLH
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Re: Changing tire profile
225/40-18 front and 255/35-18 rear are the stock size for non ///M E-85 roadster with staggered size tire setup. Stock size for the ///M is 225/45-18 front and 255/40-18 rear.
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Re: Changing tire profile
Yep the pics work, but I don't think that they are very accurate, since the rim itself is smaller in the second pic. Don't think the difference would be quite as dramatic visually.ga41 wrote:I wouldn't, partly because I think my speedometer is already not that accurate but mainly because I think it would make the tires look too skinny in the wheel arches. If it was a track set of wheel/tires then I wouldn't care but not for a daily driver.
The pictures below work?
- ga41
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Re: Changing tire profile
Well go by the pure numbers then, there's a 1.2cm difference in sidewall height...
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- M@r]{
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Re: Changing tire profile
If the OP is ok with a 4% inaccuracy in his speedo, which he has already mentioned he is, the only other thing imo is the gap in the arches, nothing a 10-20mm drop wouldn't sort out.
A 60% saving in tyre cost can't be ignored.
Could put it like this; whats better, going for premium band tyres with a lower profile, or going for a higher profile but on a budget tyre?
A 60% saving in tyre cost can't be ignored.
Could put it like this; whats better, going for premium band tyres with a lower profile, or going for a higher profile but on a budget tyre?
2006 Lotus Exige S
2006 E61 535d M-Sport Touring
2006 E61 535d M-Sport Touring
- Dreamer
- Senior Member
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Re: Changing tire profile
I have the lower profile rubber on my M wheels and they look much better. The car sits lower too remember. Go for it.
///M Interlagos. Champagne leather