I'm upgrading to aftermarket wheels with summer tires on my new '11 CS and since the OEM 18's are probably worthless, I'm thinking of slapping a set of mud and snow tires on them so occasionally I can take the car off road and go play in the snow during winter (I'm in Socal and I walked around outside in short sleeves). I searched and saw some recommendations but most of the off road tires would have much bigger overall diameter than the stock tire/wheel's 29". What is the best mud/snow offroad tire for the stock 18's out there?

 

Try Dunlops or Pirellis, I have had very good exp with Dunlops on snow and ice

 

I run TOYO Open Country A/Ts in 255/55R18 because the OEM Pirelli Scorpions ATRs couldn't handle the ranch road I drive regularly. Getting about 30K miles per set --on set #2.

The TOYOs are not much better offroad, although they do get me through the mud that stopped the Pirellis. They are okay in snow, and not bad back on the pavement.

I too would like to find a more competent off road tire that doesn't make the S feel like my F250 on the highway.