I bought started wearing my first pair of Span Triax when I was training for my first marathon. I initially had problems with blisters, but when I switched to Wrightsock double layer socks, I was OK. My first pair made it through the marathon and I logged over 600 miles on them while at an average of 190 lbs. I trained more intensely for a second marathon with my second pair, and so far they've carried me through almost 500 miles. Excellent stability running shoe, even for bigger runners.