Coincidentally I was just thinking about that on my way home last night. It was a light rain, and I still haven't placed a fender section over the top of the front tire. I was watching the spray, and wondered why I'd never noticed it that clearly before. Duh, it's because I'd never had the light on the fork, underneath it. It's a fountain lit up from below and you can clearly see where all the water goes. Almost all of it is straight out from the outer circumference and there's a smaller amount at angles, but still coming off from the outer surface. It might vary with tire shape, and with knobbies or deep tread who knows, but anyone curious can see for themselves just by strapping a light down there and riding a rainy night!