Tire Sizing for BMW Z4 M Roadster
I have gone through a number of sets of tires in my days. First with my ever hungry Mazdaspeed Protege, and now with my Z4 M Roadster. When it came time to replace my tires on the BMW, I had a general lack of information on sizing, through experimentation and research on the internet I have come up with the following sizing information that is known to work:
Stock Tire Setup
- Front: 225/45/18 – Continental ContSportContact
- Rear: 255/40/18 – Continetnal ContiSportContact
Known Working Tire Setup
- Front: 245/40/18 – Goodyear Eagle F1 Asymmetrical
- Rear: 275/35/18 – Michelin Pilot Sport PS/2
I am planning on going for the Goodyears in the rear once the Pilots wear out. However, due to a flat and limited tolerances for me to wait for a tire shipment, I had to get the Michelin’s in a last ditch effort to make it home.
For a time, I had the 275 pilots in the rear, and the 225 Continentals in the front, to say the least – the prodominant handling characteristic was understeer, unless you were very very aggressive and steering with the rear wheels.
This produced some unwanted wear characteristics on the front tires at trackdays. It shredded the outside of the front tires after a day at the track. Due to my lacking of bravery in some of the corners, catastrophic understeer was induced (for great safety).
