This is the second version of a 650b mountain bike from Ritchey -- Tom started to design his first in 1977. Even back then, Tom had a feeling that there was an advantage to the "middle" wheel size, but it took the rest of the cycling world three decades to figure it out: a 650b (or 27.5") wheel provides the bump-eating smoothness of a 29er, with the light, responsive feel of 26" wheels. Finally, the era of the 650b wheel is here.
Strengths: I have the frame and fork with my own build of parts, very light for steel ride quality is outstanding and its not too expensive. Cheaper than a custom made steel frame so excellent value.
Weaknesses: none! Though the lack of a decent fork (I'm using a fox 2012 RLC F32) if you want suspension is the only issue. a 26' fox will fit but only with a 2.1 tire or smaller.
My build comes in at 10.5kg but I have seen one that is 9.25kg with XX1 and the ritchey carbon fork.
I am running hope pro 2 evo hubs/race x2 brakes/ 160mm saw tooth rotors. Enve seat post Pro XCR carbon bars & stem. M980 11-36 cluster, M770 180 cranks CK ceramic BB, m980gs rear d, dura-ace front d with spleen adaptor, 26/38 rings.
This is a g8 bike and very rare here in NZ, it gets lots of attention but most of all it is a g8 ride. I have a series of pics of the build on the 27.5 forum.