I sorta disagree. I have toured on both mountain bikes and road bikes. I’ve toured through Europe and along Highway One on a road bike and in Hawaii and Northern California on a mountain bike, and the differences I found are such: 1) Lower back pain — I found that I was a lot more comfortable over the long haul on a road bike. I was stretched out more, which is much better for cramping and for general muscle fatigue. Mountain bike frames are generally made for riding single track, or at least on the dirt; if you are touring on dirt roads, then this works fine, but the tube angle and the short top tube length will definately affect you after about mile # 90.
If you look at the geometry of the classic touring frames, you’ll find much more relaxed angles than say a Klien Quantum. This is to provide the rider with the maximum comfort for the times he/she spends 8 or 9 hours in the saddle. 2) Availability of parts — This far too often overlooked, but in this case I found that a mountain bike is far better off than a road bike. Bike shops are full of mountain bike parts due to the popularity of mountain bikes. Since I now tour on a road bike, I stick with VERY available run of the mill, high quality parts; you just can’t always replace the esoteric. 3) Skinny tires — This isn’t exactly true. The last time I toured I bought Continental 35mm touring tires, and barely felt the road. The other benefit from those “skinny” tire is that they raise your low riders up front (If you are touring with a full set of panniers) high enough that they don’t rub when you corner. When I toured around the Big Island, I almost wore my front panniers through from them rubbing. When I toured along Highway One, I was on a road bike, and those “skinny” tires raised the panniers up high enough that it wasn’t a problem. 4) Triple rings — Touring bikes have had triple rings for years; these did originate with the advent of the mountain bike. As a matter of fact, you can buy Shimano 105′s now that accomodate a triple ring, and the STI road bike system will work with triple rings. I was going to switch over to triple rings on my last tour, but it wasn’t worth it to me.
I just got the biggest rear cluster Ultegra could handle on the rear and used a 39 chainring on the front, and I had pretty near a one to one ratio. I didn’t feel at all bent out of shape on the ride down Highway One. If I was in much steeper invironment, I would have had to make the switch. 5) Road bike market shrinking — Yes, I suppose it probably is, and this is a shame. Some of the old classic frame builders (Bob Jackson comes to mind) are still around, but too many of them have gone by the wayside. But I think this comes from the idea that a mountain bike gives the IMPRESSION of being more comfortable. A touring frame is a specialized bike; it is made with the specific purpose of providing you the most comfort for the longest period of time. A subsequent post to the original post speaks about touring being an incredible experience, regardless of what you ride. I thoroughly agree with this sentiment of not confusing the dancers with the dance. Touring is an incredible, intimate way to see the world; it’s a shame that not more people get out an do it.