Winters aren't fitting! Any ideas?

I

ironictwist

Member
Evening!

Currently running a set of Falken 452's on 225/45/16's...I've nabbed a set of part worn Dunlop winters which are unfortunately 225/55/16's.

Now unfortunately because of the way the Z's setup apparently the tyres due to the increased profile are a) going to rub against the inside of the arch should you go full lock b) Due to the level of suspension travel (stock setup) the level of travel will be tiny/non existent (apparently) - As a result my local tyre guys arent keen on fitting & reckon they won't fit.

Friends of mine that own TVR's & the like suggest 5mm spacers which SHOULD sort it...But I'm unsure! Any thoughts?!

Thanks in advance chaps!
 
The issue is that the 225/55-16 tires have a running diameter of 25.7 inches. Non-M Z4's are designed for a 25 inch diameter tire. I know you can run a 25.4 inch diameter tire on both the front and rear of the Z4 without issues because I did on my 2 previous Zed's. My guess is that you likely would not have a problem on the rear but the front will be very tight. May or may not work and perhaps someone else here has more knowledge.

About the 5 mm spacers. That will move the tire (and the rims) out by 5 mm. I'm can't see how that would help unless you have an offset issue with your rims. If you are using stock BMW rims I can't see why that would be of any help.

Also, was just thinking... :smart:
If the tires you want to fit are worn down enough then perhaps it won't be an issue.
 
Ah WLH! Thats very handy, thank you!

The tyres are down to about 5mm all round...I may see if I can nab a pair of 225/50/16's for the front (Or may just get a fulls et if I can find some) which MAY just handle it for me (Seeing as 50's of that size appear to be one of the many recommended sizes for M+S tyres on the Z)
 
My winter tyres happen to be 1 profile up 255/40R18 and 225/45R18 which gives a wheel diameter of 26in and I don't have any problems with rubbing.

The speedo reads about 1 or 2 mph higher when checked against GPS but this just makes it read actual speed rather than a little low.
 
ironictwist, the standard size for a 16" wheel is 225/50 R 16. AT 225/45 R 16 your Falken's are actually 5% less than they should be :?
(there is a link to the owner's manual in my signature if you want to confirm for yourself).

So, if you went with the 225/55 R 16 you would be adding 5% (11.25mm) to the profile, not 10% (25mm) as your current setup would suggest, and what they tyre fitters would be working off. You may get away with this, essentially what Half Colin is doing with his setup.

However, what will cause you problems is adding spacers - this will probably cause the tyres to rub on the wheel arches / outer liner inside the arch - some people have experienced this running ///M wheels (with a wider offset) and profile tyres on a standard car, although I can't remember how much wider the offset is. If you're going to all that trouble just buy some new tyres! In the right size :P

You shouldn't have any problems selling your tyres and buying others - if you got them from a dealer see if they will do a swap and you pay the carriage... the smaller tyres should be cheaper. Just make sure you stick at around 5mm tread as winters run out of steam at 4mm - which is why you see so many part worn winter tyres on eBay with 4mm of tread, for normal tyres it sounds good but for winters is a waste of money.
 
For all your tire size calculating needs visit: http://1010tires.com/TireSizeCalculator.asp :thumbsup:

It wont tell you if it'll rub or not but it's very useful for calculating the size diffrence of various profiles and the speedometer difference as well.
 
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