I have the WinterSport M3 tires (225/55/17) for the 4th winter season and they seem to handle much worst in the ice this year. I probably have a bit over 12,000 miles on them. The treads look good.

What gives... I expected over 20k miles. Any experience with these tires?

 

How much tread is "good"? Winter tires depend on the sipes and tread depth for their performance, so they should not be used down to the same treadwear as normal tires. I think they are at the end of their life and you need new tires soon

 

Good guess. There is 5 to 6 mm tread left but the top of the tread is at almost the same height as the wear indicator (i think that is what it is). What is the original tread depth on these winter tires?

 

According to Dunlop, your M3's started at 11/32's (8.7mm) new.

Most winters have between 10/32 and 13/32 of tread when new and manufacturers recommend replacing them with at least 5 or 6/32 remaining. My Toyo Garit HT's (215/55-17 H-rated) were 12/32 (9.5mm) new and are into their third winter. When I took them off last spring they had logged 7,800km (4,800 miles) and had worn only half of 1/32.

On the other hand, my wife's Goodyear winters are wearing about twice as fast (1/32 in 6,300km) and my son's Nokian Hakka's are wearing half as fast, almost no measurable wear in 13,500km. Go figure.

 

I'm with everyone else on purchasing 17" rims with snow tires. I purchased mine used (around 6,000 miles) for $550. Doesn't look too bad either.