I have an 09BoxS with 19" summer tires on Turbo wheels. I thought that circa 50 degrees F (road temp, however you figure that out) I should be very cautious driving that configuration but a service guy told me they should be OK down to freezing. Any comments? This week it is colder than normal in Chicago!

Also, any opinions on 17" vs. 18" wheels/winter tires. I already have a set of 17" (Box II wheels) from a prior car that was totaled in a flood (very sad). The 17" should in principle cut through snow better. I drive the car in winter sometimes (can't go all those months w/o it!) but admittedly not through snow. In principle I would get better performance with 18" but does it matter for relatively cautious winter street driving?

 

First off, summer tires will NOT perform well at all down to freezing. They will become hockey pucks and slide all over the place. The "service guy" that told you that should be shot.
As for winter wheels...driving in Chi-town I would stick with 17s. Yes, 17s will handle better in the snow but more importantly they will withstand Chicago's winter potholes much better due to the added sidewall. If you dont think youll have it in much snow I'd opt for a performance winter tire...such as a Michelin Pilot Alpin 3. GREAT tire that will still perform in dry....but able to handle cold and snow as well. Good luck!

 

Thanks that is very helpful. I'll pass it on to the service man. I used to be a decent hockey player but never tried it on frozen tires...

And I did not consider your point regarding the 17" tires. Very helpful too; greatly appreciated.