I thought I had wheel sizes figured out. 29in for cross-country hardtails and short-travel FS bikes, unless you're very short. 26in for piss-about hardtails and long-travel FS bikes. And 650b waiting in the wings, driven by some big brands. The 650b-specific forks and tyres that have showed their faces thus far suggested that the inbetweeny wheel size (and, to digress for a moment, I don't want to hear any more nonsense about how it's “halfway” between 26 and 29in – it's not, it's closer to 26 than 29, and very few “26in” or “29in” wheels are those diameters anyway. My 26in wheels are more like 27.2 and plenty of 29in setups are over 30. Er, where was I?) was destined for the kind of longer-travel, burlier applications for which 29ers present packaging and wheel strength issues.
And then the first round of the UCI MTB World Cup happened. No big name showed up on a 29in DH bike. So far so good. But Nino Schurter lined up for the men's XC race on a 650b Scott, and went and won it. The floodgates look likely to open. But is that a good thing?
There are some key differences between the 29in and 650b phenomenons. 29in wheels have been around for a long time – I rode a Willits in 1999 or so, and they've been available from mainstream brands for a decade. It's a mature technology, with forks and tyres readily available and geometry mostly sorted. But it took a while to get here, and that it did is in large part down to the persistence of the niche builders and early-adopter grassroots enthusiasts that just wouldn't let it go. Most of the industry was reluctant, to say the least. In that sense, the growth of 29ers has been from the bottom up, end-user-driven.
650b's not like that. Initially the inbetweeny wheel size looked set to follow a similar path to 29in, with a small but vocal band of (often bearded) enthusiasts pushing it and hoping enough people would listen to give them a choice of more than one tyre. It didn't work. 650b fizzled and all but went away.
But now it's back, but at the behest of some very big names. Scott's showed its hand and other big players have plans. The major fork and tyre manufacturers have 650b product lined up ready for 2013 ranges. And that's the difference – it's top-down, driven by manufacturers rather than riders.
That's not necessarily a bad thing, although there's no shortage of historical examples of things foisted upon a reluctant market that go on to vanish without trace. But you have to ask – does anyone actually want, let alone need, another wheel size?
Racers, of course, will latch on to anything that might give them an edge, however small. At World Cup level, every little helps. You can't argue with Schurter wanting bigger wheels but not wanting his bars at chest height. It really doesn't matter whether there's an real, physical performance advantage either – if you're more comfortable on your bike you're going to perform better. Hell, if you like the way your bike looks you're going to perform better. Funny things, brains.
Manufacturers clearly want something new to sell. It was ever thus, and more so in an essentially static mountain bike market. These days it's as much about selling more bikes to the same people as it is about bringing new people in. But this could backfire. Believe it or not, there's a limit to how many different bikes any one person can sensibly own (and yes, you may insert your own “n+1” line here). And the MTB marketplace is already quite bewildering, with suspension travel at every 20mm increment from 100 upwards, bikes with the same travel having wildly different geometry and being good at different things and two wheel sizes. Adding in a third is going to result in some pretty scary product matrices.
The other thing is that for most people, the people who don't race (or do, very occasionally and not particularly seriously) it really doesn't matter. Theoretical performance improvements don't matter when you ride for fun. Actual measured speed differences don't matter if you're always taking slower, more interesting rides or going the long way because the trails are more fun.
That said, I don't race and I'm sold on 29ers. On hardtails, at least. They're fun.
So there's my conflict. On the one hand, I like innovation. I very much appreciate the fact that the bikes we have today are better than the ones we had ten or twenty years ago (and it doesn't really matter what “better” means here either). I like freedom. The UCI deciding to legislate against a wheel size for racing or is not something I want to see. And I like choice. But only – and here's the rub – up to a point. Mountain bikes got popular in the first place because they were bikes that you could do pretty much everything on. Now we've got specialisms and niches all over the place. It's possible that 650b could represent a move back towards all-rounders, a kind of Goldilocks just-right wheel. Or it'll represent more fragmentation, more confusion and, ultimately, fewer sales. And that would do nobody any good.