First we had 29"ers come along and mountain bikes gained another wheel size. Is mountain biking poised to gain another? I just recieved my newest "Dirt Rag" and there is a short article in it about Grant Petersen and his prototype "Bombadil" mountain bike with 650 B wheels.
650 wha...? Yeah, another wheelsize. It's not new either, no......not at all new! It gained noteriety in the 40's-early 60's as the standard sized wheel for French touring/camping bikes. It was ressurected for a very brief period during the earliest phases of the modern mountain bike back in the early 80's. An example would be the Raleigh Tamarack Mountain Tour. Now, it has regained a toe hold mostly due to Mr. Petersen's influence with his companies growing roster of 650 B wheeled rigs.
So, what's up with this 650 B stuff? Why do we need another wheel size? Well, it could be argued that the 650 B is better than a standard 26"er (larger diameter, with all of the attendant benefits) and smaller than a 29"er, (quicker acceleration, lighter). Maybe it's the best of both worlds that the "69er" guys are trying to acheive. Maybe it's not enough of a difference either way to make it worthwhile.
The main point behind it all anyway, in my opinion, is to develope a "do it all" bike that folks can use for real needs. Like commuting, running errands, and the like, but also be able to do road rides and light off roading. A practical bike in the sense that it can be a tool that does many jobs. Not unlike what the industry was trying to do with hybrid 700c wheeled bikes ten years ago, but left behind for their versions of couch bikes and status symbol fitness rigs.
From a bigger wheeled mountain biking perspective, will 650 B ever take hold? Will it become the "other" other wheel size? The answer from a reality based perspective? Ahhh..........probably, no. Too much already invested into 29"ers, and no huge benefit to going that direction will probably not get the manufacturers attention. Will 650 B mountain bikes never materialize? Not if Mr. Petersen has his way, and he has an amazing ability to get the seemingly impossible done. Look at what he's done in 650B already- a wheel size that was pretty much dead only five years ago- and you can see what I mean.
It'll be interesting to see if this "Bombadil" ever comes bounding down a trail someday, singing it's non-sensical tune, looking rediculous, but saving the day none the less.