So I bought a Bianchi '04 Pista a week a go to use to haul the kids around in the Burley. I've been using a 42x18 freewheel. My road bike is down due to the fact that the rear wheel is in for service and Tuesdays are my TT night. So although I had the brakes removed from the Pista (I took them apart to clean them) I took it out as a fixie (48x16). I've got a great 8.9mile TT loop right outside my neighborhood. It's a pretty tough loop with lot's of rollers and a stiff head wind on the out section of the lap. My best time on my road bike is 20:32, last night I dropped 57 sec off that time! Now the head wind was only about 15mph last night and usually it's in the higher teens or low twenties so that helped but it can't be the only reason. It must be that I've been "cheating" in my pedal stroke with the road bike, something you can't do on fixed bike. Me thinks that Santa might be bringing me a really nice track bike for Christmas!