I run Continental Top Contact Winter 37 x 700 front and rear studless during the winter here in arid Colorado, but recently bought one Schwalbe Winter 30 x 700C for the front with studs for use when things get more nasty. Mounted it on a spare rim. I thought I'd work my way into studs gradually, just use when necessary, and so far this is working. But then, my rear tire is not a summer tire, it's a Continental Winter. For me, the purpose is same as some others, to limit the huge weight and rolling resistance penalty from studs.