As stated by others in the above posts, a mountain bike, or it's cousin the hybrid bike, are both capable to ride on a paved surface; aka road. Tires, saddle, gearing, geometry, manufacturer, bike fit along with a host of other details will make a difference in the enjoyment of your ride. Ya pays your money and makes your choice. I rode the LACBC River Ride, 36 mile loop, this past weekend on my factory stock Specialized Hardrock Disc 26er. Overall I had no major problems. Comfort was good until the last 3-4 miles since the saddle is a little too narrow for longish in-the-saddle riding; but for trail riding, it works very well. Yes, I was slower than most folks on a road/race bike but I did finish and passed a number of roadies mending a flat tire along the route. Felt like the tortoise from the tortoise and the hare fable. Just my $0.02. PG.