OEM

[Vondelta]

What is the size of the widest tires that will fit on OEM size Z4MC rims without having a rubbing or spacing problem?

[Finnegan]

Originally Posted by Vondelta

What is the size of the widest tires that will fit on OEM size Z4MC rims without having a rubbing or spacing problem?

Simple answer is that you can go up to 245 in the front and 275 in the rear with stock wheels (based on the wheel size). Seems like a lot of folks here have/are running this and I haven't found posts noting rubbing issues, although obviously non-OEM springs might create more potential for issues. But there are pros and cons to going "max" on the stock wheels. My M3 has 265mm tires stock on 9.5" rims. Go max on the 9 in stock ///M wheels and you lose some sidewall stiffness. If you're in a really wet region there's increased chance of hydroplaning (I just learned these two things today).

Here's a good tool... http://www.1010tires.com/TireSizeCalculator.asp which I used to populate the following grid.

EDIT: Jragan also put together this grid for our car which is super-cool. Lots of folks are running max rubber (per this chart)....I've decided not to since we'll probably be going with an alternate set-up for "off road use".

OP, sorry if I've hijacked your thread...it seemed like this might be the direction your thoughts were heading so I tried to pick things up...

[ANILE8]

275's on stock 9" rims is a little too wide IMO. Dunlop recommend a maximum of 265's for 9" rims and a maximum of 245's for 8" rims.

Use a race tyre not a hard as nails road tyre if you want the best performance. Dunlop DZSPZ1 are ok but far from a race tyre capable of ultra highend performance. The difference is stupid.

Before you all start, yes I do use them on the street come rain/shine and without issues.

I use Dunlop Racing DZ02G - 245/40 R18 for the front and Dunlop Racing DZ02G - 265/35 R18 for the rear on stock rims.

[Finnegan]

Originally Posted by ANILE8

275's on stock 9" rims is a little too wide IMO. Dunlop recommend a maximum of 265's for 9" rims and a maximum of 245's for 8" rims.

Use a race tyre not a hard as nails road tyre if you want the best performance. Dunlop DZSPZ1 are ok but far from a race tyre capable of ultra highend performance. The difference is stupid.

Before you all start, yes I do use them on the street come rain/shine and without issues.

I use Dunlop Racing DZ02G - 245/40 R18 for the front and Dunlop Racing DZ02G - 265/35 R18 for the rear on stock rims.

Thanks! No braking or other issues with the 265/35 R18 on the rears with the 2.8% diameter difference from stock? How do you find the understeer situation with this (less) staggered set-up?

[ANILE8]

Originally Posted by Finnegan

Thanks! No braking or other issues with the 265/35 R18 on the rears with the 2.8% diameter difference from stock? How do you find the understeer situation with this (less) staggered set-up?

I have not noticed any ill effects at all to speak of running a 245/265 ratio.

The limits are so much higher with genuine Dunlop competition tyres that understeer becomes a non issue. Running this type of tyre redefines what is considered humanly possible for a particular vehicle.

After a while the performance and confidence a full on competition tyre installs into the driver becomes so addictive you will not accept anything less and you will want to run them all the time on your street car. That's why I cannot go back to a street tyre even for my everyday use like so many on this board.

[Finnegan]

Thanks for the follow-up input.

I'm going to view the R-compounds as something to aspire to for now. I really need to work on my skills and for me there's something to the idea of staying with something that points out my errors initially (more street-based tires). We have very heavy rainfall where we live Sept - April--enough that driving even with wet-weather-oriented tires can be a challenge at times. So that's another reason for us not to go that route for street use.

If I end up with another set of wheels, which I probably will, R-compounds may be a consideration a few seasons in the future, assuming my driving level is worthy of them.