Just got my first SS (GT Peace 9r), and had my first ride yesterday thru the snow. The ride along the dirt snow in packed snow was fine, but when I hit a flat trail that was semi-packed from walkers and skiers, I had a heck of time. The gearing on the bike is 36x18. I think if I switch to a 22 cog it would help in the slow going of the snow trails. I have an old cassette in the parts box, just wondering if I can take the cassette apart and use a cog from there? Its a 9 speed cassette, so I figure the teeth of the cog will be narrower. Or should I just go buy a SS cog in 22 size. Given the position of the axle, I think I'll need to buy a new chain to handle the new cog, so I need to place an order anyway.