Zero fork rake (offset) results in longer trail and sluggish handling.

Framebuilder Dave Moulton says in one of his blogs on rake and trail that for a road bike with a 73 degree head angle the optimum trail seems to be around 2 to 2 ½ inches (5 to 6.3cm.).

From the diagram below, you can see that zero rake on a bike with a 73 degree head tube angle and 700C x 25C tires, the trail would be a whopping 103.3 mm (10.33 cm).