Last week I reported mounting 700x38 cyclocross tires on the Gary Fisher Superfly to get better roll on the road, while still maintaining enough off-road-ness to ride the HD Bluff trails occasionally. I have about 75 miles on the set-up.
The road performance is outstanding. These tires are light and give good traction with little rolling resistance or noise. They make the carbon fiber mountain bike feel almost like a road bike and a lot of fun to ride on the road. I also did a test run across the bluff on dry trails to test the off-road capabilities.
The tires performed well for climbing, stopping and maneuvering on the dry trails. The were also fast rolling and improved the flick-ability and quickness of the bike. I did notice that the rear would break free if I hit a berm while carrying a lot of speed, but is was nothing unmanageable.
The big difference was the feel of the ride itself. Going from high-volume, tubeless tires with 30 psi to low-volume 80 psi meant for a lot of chatter when riding over the rocks. I pumped them to the maximum pressure for the road and to ensure I did not get a pinch flat over the rocks. It was not the end of the world, but you could definitely feel the difference.
Overall, I think the ride quality is worth the trade-off for speed and noise since I mostly ride the bike on the road for now. The wheels are still set-up for tubeless tires, so I may just find a tubeless cross tire to see how low I can go with the pressure and still keep a fast rolling tire.
Now if I could just get that trail of soap bubbles to stop following me around.