If you are coming from riding a CX bike on the road you should be looking to get a road oriented SS or geared bike (or possibly another wheelset with 23-28mm tires_ if you want to increase your average speed on longer road rides. When I compare my road oriented ss and geared bikes I don't notice any meaningful difference in average speed.
Last edited by Charlie_Zulu; 11-30-11 at 08:21 PM.
Reason: extra info