bfloyd

I tried a search for this but didn't come up with much (maybe I searched wrong). Anyone try one if these yet? What's the purpose behind the larger wheel up front? Are the geometries different or can any mtb frame work with the correct fork length? Thanks.

stet

the geometry is pretty specific to the bike so it's not such a good idea with just any ole frame. the idea with 29'ers in general is that bigger wheels means a bigger contact patch with the trail which means more traction. the larger circumference of the wheel means that it will roll over rocks and ruts without being impeded as easily as a 26" wheel. the larger volume tire means a plusher ride and a bike that is less dependant on suspension. the larger wheel also means more rotational mass which is nice once you get the bike up to speed (it takes less effort to keep it up to speed). the downside is that 29'ers handle a bit more sluggish on tight singletrack and they don't accelerate as quickly. so a 69'er is kind of a compromise between the two bikes. it accelerates well because of the smaller wheel up front, the handling isn't as slow, and you get the roll over anything momentum and traction of a bigger front wheel.

NormanF

It works with any classic mtb frame geometry. I installed a Bontrager Race 26" race fork with disc brake along with a 29" wheel. The frame geometry was changed very little. After taking my 94 'Gary Fisher Aquila 69er out for a spin, I can see the bigger front wheel just makes the bike roll faster. It reduces overall riding effort. This is a sweet setup- as long as you use the correct fork.