I ride a single speed road bike when not on my mountain bike. Welcome! I am using a rear joytech wheel laced to a BMX hub and 17t freewheel, with Shimano 600 cranks and a 40t chinring. So, I am running a 40x17 setup. It is fast enough on the flats to go 30 miles in 1.75 hours, and climbing doesn't murder me.