Niner SIR 9 Frame - 2016

Niner SIR 9 Frame
Shown for color reference only. Price is for frame as defined in specifications.
  • Shown for color reference only. Price is for frame as defined in specifications.
  • Color: Blaze Yellow
  • Color: Blaze Yellow
This item is currently not available.


Niner’s SIR 9 is a savvy reminder why every great bicycle comes down to three things: good ideas, good workmanship, and good materials. If any of these are missing, you cannot have a great bike. The SIR 9 combines these qualities in a soulful ride that reminds you of every great day you have spent on a mountain bike.

Niner worked with Reynolds to produce a 853 DZB (Double-Zone Butting) steel tubeset that uses multiple wall thicknesses and a Niner-specific down-tube bend to maximize strength and torsional rigidity at the head tube-down tube intersection while maintaining adequate clearance between the down tube and front tire, a tricky balance for 29ers often requiring the addition of gussets (and weight) or sacrificing strength and safety. Another great, function-first idea is Niner’s Biocentric II eccentric bottom bracket with an 8.5mm spindle offset for a dramatic range of adjustability with absolute reliability thanks to the two bolts it uses to apply a clamping force on the outside edges of the BB shell, eliminating the possibility of ovalizing or indexing the shell itself. The Biocentric II allows clean, rock-solid single-speed setups, manual multi-gear swaps without chain length or brake adjustments, and BB position adjustability for fine-tuning your geometry.

The use of a tapered head tube offers multiple advantages, not the least of which is the reduction of fork deflection. This keeps the front end tracking true when the trail throws everything it has at you. The tapered head tube also allows for a larger contact area at the critical head tube-down-tube intersection, contributing to the increased torsional rigidity and added strength that every rider can appreciate. The SIR 9 also employs through-axle rear dropouts to better take advantage of custom-bent stays and investment-cast bridges that culminate in better power transfer and more responsive handling. Reignite your purist mountain biker soul on Niner’s SIR 9.

The frame comes with derailleur hanger, single speed insert, cable retention hardware, BioCentric II bottom bracket shell, headset, YAWYD top cap, seat collar, and rear through-axle. Build it any way you like for a beautifully-riding bike that is yours and yours alone.


Frame Reynolds 853 DZB steel w/142 x 12mm through-axle
Headset Included, w/ YAWYD top cap
Bottom Bracket BioCentric II shell
Seat Binder Included

* Subject to change without notice.

Part Numbers

Option UPC MPN
Blaze Yellow / Small 010011403554 01-001-14-03-55
Arctic White / Small 010011203307 01-001-12-03-30
Blaze Yellow / Medium 010011404551 01-001-14-04-55
Blaze Yellow / Large 010011405558 01-001-14-05-55
Blaze Yellow / X-Large 010011406555 01-001-14-06-55
Arctic White / Medium 010011204304 01-001-12-04-30
Arctic White / Large 010011205301 01-001-12-05-30
Arctic White / X-Large 010011206308 01-001-12-06-30