I always thought single speed was just for BMX and kid's bikes. I could definitely see switching to 1x9, but I use like 4 gears just on the relatively flat 1/2 mile between home and work and 7 of them on the trail (I never shift the front). However, I've read more than enough about people's SS bikes to make me wonder. Is it really that good even on a fair mix of up and down? I noticed even the TransAM comes in SS flavor. Do you folks with SS bikes ever ride all mountain?