I added a longer mudflap to the front raceblade and it works well enough for keeping the spray off myself and off the drive train. It won't keep grit out of your front brake mechanism or headset.

It's probably worth mentioning though that the cantilever brakes that you often find on bikes with clearance for wider tires aren't protected even by full fenders. In fact, fenders probably end up directing even more crap at them.