My track bike handles best on a smooth track when it has the stock fork with a short 38mm rake. If I ride this same bike as a single speed on the road, it handles better with a 45mm road fork. This is assuming the same frame geometry, head tube angle, tires, etc.

A short rake increases trail and makes a bike track straighter hands-free, when ridden on an ideal smooth surface. Old time photos of track motor pacing show specially modified bikes with backwards forks (negative rake). I used to think this was to allow the bicycle to more closely follow the pacing vehicle, but it was most likely done to improve high speed tracking and stability.

Then why do road bikes have longer fork rakes and touring bikes have fork rakes that are longer still? My theory is that because of imperfections in the pavement, a longer rake (and thus shorter trail) makes the bike less "twitchy" because of decreased "bump steer". When the front tire hits a bump or crack in the road, the force is usually unevenly applied (more on one side of the tire than the other). This causes a slight deflection of the tire that changes steering (I am going to call this "bump steer", but that term may have different meanings in the motorcycle and auto industry). A bike with a long rake will have a shorter trail and thus a shorter lever arm in which a bump can change the steering. Thus a longer rake decreases the bump steer effect and a road bike will feel more stable and less twitchy than if this same bike had a short raked fork.

This would explain why my track bike handles best on the road when it has a 45mm road fork. It would explain the fork geometry trends of current and traditional track, road, and touring bikes. It would explain why a carbon fork feels better on the road as it absorbs some deflection energy and decreases bump steer, in addition to the vibration dampening effect. It would suggest that when we convert a track bike for road use (either fixed or SS), we should install a road fork if we want optimal handling.

Is my theory correct or is it a load of hogwash?