Just got back from the tire shop, where they mounted 225/45/18 Dunlop SP Winter Sport M3 snow tires on my spare set of stock 18" rims, and put them on my car. Both the tires and rims were acquired slightly-used through this site, BTW. No TPMS in my "winter wheels", and no problems in mounting and balancing.

Anyway, searching around this site, I noticed a reference to page 4-9 of my 2004 RX-8 manual, which specifies that snow tire pressures should be set 4.3 psi ABOVE the 32 psi recommended for the stock tires. Does anybody know the reason for this? And should a "performance" snow tire be any different? Is it strictly for traction on snow/ice, or would the recommendation be different for driving on dry roads at low temperatures? Thanks!

 

I believe it is has to do with the fluctuation in temperature. In the winter the tire temperature doesn't get nearly as warm as in the summer because of this the tire pressure does not raise as much.

I am running the Dunlop M3 Wintersports also. Ran them last year and was very pleased.

Mine are on 17" rims with TPMS. I had one day last year that it dropped down to 70 degrees below zero, Farenheit. The tire pressure management light kicked on when I first started driving because the low temp had lowered the tire pressure.