I don't have 'm on stock, but I have them myself, and can only agree with what Cliff advised. They are very warm, but are very, very bulky to use on a bike. Changing gears is a PITA, either you change the position of the gear pedal, either you change gears up using the side of the boot, instead of trying to fit the boot underneath the pedal.
If you're looking for something to keep you warm, no matter what, they're the boots you need. If you don't really need the warmth, but are just looking for something else to use, I'd look elsewhere.
Grtz, Philip!