The Niner S.I.R. 9 SPX 2011 Mountain Bike is the most versatile bike in the Niner stable, fusing the "steel is real" feel of Reynolds tubing with the ability to run the frame as either a geared bike or single speed. The S.I.R. 9 uses the same custom drawn Reynolds 853 tubing as the M.C.R. 9 and combines it with Niner's ultra-light eccentric bottom bracket. Custom "breezer" style forged dropouts have a replaceable alloy derailleur hanger and come with an insert piece for running the bike as a single speed to eliminate the unnecessary derailleur hanger for a clean look.
Niner S.I.R. 9 SPX Mountain Bike