My cars have worn separate sets of summer and wheels & tires for about the last 15 years, so I'll report my history / experiences.... Best time to swap them is around Halloween and Easter for prairie winters IMHO.
All were worn on A2 VW Jetta ('86, '92) unless specified:
175/75-13 Goodyear F32-S, in 1st and 2nd gear the car would pull through a deep snow-covered field with 3 of my younger siblings as passengers. Excellent traction. Would buy again, except for the fact that snow tire technology started improving and becoming more commonly available....
175/75-13 Dunlop Graspic (can't remember the specific model) - studdable winter tire, square tread blocks, I ran them without studs, noisy and crude but moderately effective, could be unaffectionately called "dumb-lumps". I purchased 2 to replace the worn-out Goodyear's. Would not recommend.
14" Toyo Observe G-02, my brother had a set of these on his Plymouth Sundance Turbo and took me out to show me what they could do. I almost lost my last meal when he merged onto a busy icy street in front of another car, the driver looked like he was in full-panic mode but my brother goosed the throttle and caught up with the traffic faster than the guy behind him could have stopped. Extremely aggressive tread pattern, although not as noisy as you might expect. I don't recall how well these tires wore but when new they sure were effective on icy streets.
155/80-13 (4.5x13 rabbit steel wheels... narrow!) - Nokian Hakkapeliitta Q, an awesome tire that lasted me 4 winters with proper rotation and seasonal changeover. My sister's husband used them temporarily after I was done with them and remarked that they still provided acceptable winter traction.
155/80-13 (5x13 Audi steel wheels) - Nokian Hakkapeliitta RSi, I was undecided between another set of Hakka Q's or the new RSi, decided on the RSi because of the cool tread pattern and tread wear indicator, also higher speed rating? My subjective opinion (from memory), I recall being more impressed with the Q as it seemed to grip and wear better. Very subjective opinion, could have been accelerated tire wear due to worn suspension parts or driving conditions (less snow).
