Carcass is hella thick, if you air them down you'll see how thick this tire is. You can't air them down like a Skat Trak and they sure don't expand like a Skat Trak when racing the hills. I tried both sets of paddles on one trip, ST will out perform them, they will hook and go! I think SH would be a good buy for those who rarely visit sand but I'll never cheap out on paddles again. I put good $'s in my motor and would hate if cheap paddles would rob performance.