flip03 said:
How fast do you think a 29er with cross tyres set up tubeless could be? Now i have not spent a great deal of time on a 29er but have spent a lot of time riding a cross bike places you shouldnt be riding a cross bike and the more upright flat bar position and proper brakes and suspension forks would have made that a lot easier.
IMO it's a misconception that narrow cross tires (and tubulars for that matter) are "faster".
You'll have a hard time beating the 'cross pro showing up to your MTB race with his UCI spec cross bike. That's not because the bike is fast (take it for a lap), it's because the rider has built the skills needed to pilot such impractical machines at top speed, off-road no less.
The rolling resistance on smooth trails is what simple people see as the thing where 29" is supposed to blow away 26". As correctly pointed out above, the size difference is not significant enough. And, I'll add, bigger might well be better, when executed properly. Wider hubs, more spokes, etc.
IMO, truth is, 29" gives a rider the greatest performance boost (and certainly greater than the realistic 350-400g weight penalty) comes from grip, comfort, braking traction and climbing traction, roughtly in that order.
The difference over a lap obivously is not 9.4% due to the 9.4% larger wheels. But riders know. Like me, I can now drop on tight singletrack the guys whom I before could not stay with. Oh, the powerful feeling of pulling away from a good bike handler on his own favorite tight winding trail...