Winter Setup for 06 Z4 M Roadster

[DaveZ]

Yes, some of us do drive our roadsters year round! :) Anyway, time to buy a winter package for the new beast and I have been going over the Tire Rack recommendations, but having difficulty coming to a conclusion. First is the issue of minus-sizing. I always did this for my old Z3. But 90% of my driving is going to be wet and dry and I have a hard time believing that 225/45-17's will put enough rubber on the road to handle the massive power of this beast. That is why I think I should stick to the stock 18" sizes. Any comments on this?

Now, for actual tires I see a different selection available for the 17" vs. the 18" packages. For example, in 225/45-17 I have the option of the Dunlop M3 runflats or the Michelin PA2s. But, in 18" the Michelins are not available and the M3s come as non-runflats. I'm leaning towards the 18" Dunlop M3 package, but I want to verify that the runflat version is definitely not available in this size?

Thanks for your help!

[Gary@Tirerack]

Keep in mind that massive power will only make those rears spin in the snow, especially with very wide tires, so dial the beast back a bit in winter and use 225 width tires for best winter performance. Driving in the dry is easy, and most drivers can adjust their driving for wet. Its that "10%" of the time that you'll be in snow that will be your most challenging driving, so IMO prepare for that condition as best you can.

Correct that the M3 runflat is not available in 225/40R18.

http://www.tirerack.com/a.jsp?a=AB2&url=/winter/index.jsp

[DaveZ]

Keep in mind that massive power will only make those rears spin in the snow, especially with very wide tires, so dial the beast back a bit in winter and use 225 width tires for best winter performance. Driving in the dry is easy, and most drivers can adjust their driving for wet. Its that "10%" of the time that you'll be in snow that will be your most challenging driving, so IMO prepare for that condition as best you can.

Correct that the M3 runflat is not available in 225/40R18.

Thanks Gary, I have to give it some more thought before I order. Going the other way, is the M3 non-runflat available in the 17" sizes?

[Gary@Tirerack]

Thanks Gary, I have to give it some more thought before I order. Going the other way, is the M3 non-runflat available in the 17" sizes?

Non runflats are now the Winter Sport 3D.

[DaveZ]

Non runflats are now the Winter Sport 3D.

Okay, thx for the info! Sorry to keep bugging you, but one last (hopefully) question. I just ran some calculations and 225/50R17 is much closer to the stock diameters (speedo error of ~0.5% fast) vs. the 225/45R17 which you list as recommended. These come in at a bit small, giving a speedo error of ~3.8% fast. However, under "packages" you only list the 225/45R17's. Is it possible to configure a package with the 225/50s?

[Gary@Tirerack]

Absolutely. For some reason BMW recommends 225/45R17 for snows, but the 225/50R17 is closer to the stock diameter. Both work with no problem.

[samger2]

Hello...here's my 2 cents...

I work for a BMW dealership in Columbus, Ohio and 90% of the tire/wheel packages I sell come from Tire Rack. I did a set up very recently on an 06 Z4...we used 225/40R18 Blizzak LM25 tires with ASA JH8 wheels. The set up looks AWESOME. Also, the JH8 will accept an OEM BMW center cap so the fitment looks seamless. Attached here is a picture. I highly recommend the ASA wheel mainly because it is hub centric...no rings needed for a perfect fit.

Here's a picture of the tire and wheel.

http://i82.photobucket.com/albums/j275/samger2/Image009.jpg