theyre not faster.

one gears the bike a little higher with smaller wheels to adjust for circumfrence.

go look at a 20" wheel folder. The guys riding those arent pushing 54 or 56 T chainrings because theyre olympians.... you make the gearing larger to accommodate the rev difference. :)

The key point is all other things being equal. If you want the same speed with a 26" wheel and a 700C wheel, you gear then 26" wheel slightly taller, so that the gear inches is the same, and wheel size stops being a concern. Having said that, 26" has some advantages, the slightly smaller wheel makes for a slightly stronger wheel under load. Wider rims and tires are easily obtained, the most common width for a 700C wheel is 25mm, the most common 26" wheel tire is 44mm (1.75"), given the same load that means not needing as high a tire pressure, and that means a more comfortable ride, without losing out on rolling resistance.

Well, I'm really liking the 29er size so far (Salsa Fargo). This is basically 700C, but with wider rims - so it's kind of like a cross between the 700C (in terms of diameter) and 26" (in terms of being able to use more beefy tires). To me, the ride just feels really, really nice. I believe that the larger diameter makes for a smoother ride than 26", and the big tires also help with that. The theoretical downside is that a 26" wheel will be stronger than a 29er, but in practice any well-built and stress-relieved wheel will probably not fail - especially if you use disk brakes (so no wear and tear on the rims).

The biggest practical downside to 29er is the lack of availability of spares in most of the world outside the USA (and many places in the USA, though bike shops are now starting to carry tubes in this size, and even tires). I have no idea what the real availability statistics are, but in any case if I were going on tour then I would probably be fitting some 700x50 Marathon XRs, and take one or two spare tires along for good measure (they are folding), and a few spare tubes too, and I'd be pretty ok with the risk mitigation there. With the large tires there is little chance of pinch flats, and with no rim brakes there's less chance of rim failure. There's a lot that can go wrong on a bike anyway that can leave you stranded in the middle of nowhere, so I'm not going to sweat the tire size too much if I have reasonable spares on hand (which I'd want anyway, since you never seem to break down in front of a bike shop - so I'd have the same spares even if I was using 26").

To me, performance wise, the 29er size gives the best of both worlds. You get a smoother ride than 26", and you get more beefy tires than 700C (which also adds to the smooth ride).

But hey, they all work. I don't get emotionally invested with stuff like this. I like 26" and 700C and 29er, they all have their good aspects. I'm currently in love with the 29er simply because I took a test ride and it kind of blew me away. But like I said, they all work fine, it's not like one's right and the other one's somehow wrong.

Neil

Read through this whole thread.
This is my conclusion.
The more you and the bike weigh,
the more air pressure you need to run.
Pump the tires up for speed(and traction?).
Period.
bill