I run 23c on my commuter and they are ok for the smooth roads I travel on. nasty to get off if I need to change a flat though. 32c on my Soma Double cross and they are very nice. Potholes don't bother them all that much. I run 1.5 continental comfort contacts on my mtb in touring mode and they laugh at just about anything under a fire road. Speeds don't differ all that much. The commuter is faster but not by enough to justify the harshness of the tires.