Originally Posted by
JeremyZ
You made a lot of good points about the versatility of a mountain bike, but this bit is totally false. There is a HUGE speed difference between a fat knobby MTB tire at 35 psi and a skinny, slick road bike tire at 120 psi.
For me, that difference is 20 mph on the mountain bike, and 30 mph on the road bike. Those knobbies are like fan blades at higher speeds. I could actually hear the wind they were moving when going down a hill at probably 17 mph. On the road bike, cruising at 17 mph is normal for me, and on the MTB with the same effort, probably 14 mph. That's only 3 mph, but if you're going to ride more than a couple miles at a time, it really adds up quickly.
I've been riding mountain bikes for 30+ years and haven't found the speed differential to be that high. I commute on a mountain bike often and even with riding off-road, it only takes me 10 minutes longer to cover the same distance.