I have the 400 g Mtn Extremes for over a year now. At least 200 miles on mine. They are the comfiest, best fitting boots I've ever used. As long as I don't climb hills. The second I start hitting any sort of incline these boots destroy my heels. I've tried different lacing techniques. Ive tried 5 insoles now. My sheepfeet from my Crispis, Superfeet orange and trailblazers, and the Sole thick and medium insoles. I've tried different socks, 2 socks. Absolutely everything I could think of and as soon as I hit an incline my heels get obliterated. It sucks because the last and general shape of the boot fits me so good. I'm throwing in the towel with these. They just don't work for what I need them for. Anyone else find a possible solution?