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Niner SIR 9 Frame

ITEM NUMBER: 175 NINSF4
PRICE POINT:
$999.00

NINER TECHNOLOGY

For every model, whether it's their lightest cross country hardtail or the burliest full suspension bike, Niner considers how each angle or length will interact with big wheels to affect the finished build.

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The basic concept of the larger diameter is simple: it will keep your wheels on top of oncoming obstacles. Rather than riding IN the terrain, you'll be riding ABOVE it, gaining more control and stability on even the roughest trails.

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PRODUCT DESCRIPTION

Niner SIR 9 Frame

At a time when carbon super bikes (including Niner's flagship models) dominate the stage, why would Niner shine a spotlight on the SIR 9? Perhaps it’s better to ask “just what is it about steel bikes?” Why is it, when you get on a steel frame, your'e instantly transported back to that first bike you had as a kid? Why is steel just as relevant today as it was 50 years ago while other materials have come and gone?

There wasn't anything wrong with the SIR 9 – like other Ninerds we ride it and love it. But something about Steel being equated with Retro seemed almost unfair to such a great bike. There is simply no reason frames built with one of the best metals on the planet shouldn't benefit from and take full advantage of cool technologies like updated headsets standards, tapered forks and through axles.

Introducing the new S.I.R. 9 – all the fun, all the advantages, all the steel. All steel is not created equal. The S.I.R. tubing is a custom-selected set that utilizes the best tube options for each application within the frame. For the front triangle, Niner used the new Reynolds 853 DZB (Double Zone Butting) tubing. Developed for mountain bikes, and specifically 29ers. For the stays, they incorporate steel custom bent in 3 dimensions – with investment cast bridges and dropouts – for ride quality and tire clearance. This shaping is proprietary to Niner and is not found on other steel mountain bikes. When combined with the new dropout system, it provides superior power transfer while preserving the compliant ride quality you want in a steel frame.

  • Custom engineered steel tubeset
  • Custom bent double-butted Reynolds 853 DZB down tube
  • 44mm Reynolds 631 head tube (ZS44 top, EC44 bottom)
  • Niner BioCentric II Bottom Bracket (uses 73mm external cup)
  • 142x12 rear Maxle
  • 74mm Post Mount tabs
  • 27.2mm seatpost
  • 28.6mm front derailleur clamp
  • Replaceable derailleur hanger or SS insert

GEOMETRY

Geometry

Size

Small

Medium

Large

X-Large

A

Top Tube Length (mm)

592

609

628

647

B

Seat Tube (mm)

394

419

483

546

C

Chain Stay (mm)

440

440

440

440

D

Front Center (mm)

651

664

684

701

E

Wheelbase (mm)

1085

1096

1115

1135

F

Bottom Bracket Drop (mm)

49

49

49

49

G

Head Tube Length (mm)

100

110

125

145

H

Head Tube Angle

70

70

70

70

I

Seat Tube Angle

72

72

72

72

J

Standover (mm)

716

736

790

842

K

Reach (mm)

395

409

423

436

L

Stack (mm)

620

637

652

671


Geometry based on 100mm fork

Rider Height Bike Fit Chart

Height

Frame Size

5'3" - 5'9"

Small

5'8" - 6'

Medium

5'11" - 6'3"

Large

6'3" - 6'7"

X-Large

Please Note: These are only recommendations. Fit is also affected by inseam, torso length, reach, component selection and riding style.

Compatibility

73mm BB width (with BioCentric installed)

BioCentric is compatible with external bearing cranksets only

27.2mm seatpost size, 400mm length recommended

28.6mm front derailleur, high mount, bottom pull

29.6mm seat collar size

Tapered headset with internal (ZS) top cup and 1.5" external bottom cup. Cane Creek standard description: ZS44/28.6|EC44/40

Small has one bottle mount in the front triangle. Medium, large, and XL have two bottle mounts inside the front triangle

Replaceable derailleur hanger or SS insert

142 x 12mm Maxle rear spacing

Can fit up to a 2.4" tire (tire sizes vary by brand, some tires may not fit)

Compatible with standard 3x chainring systems

SRAM recommends 2x chainrings; 26/39T or lower

SRAM XX1 recommended max chainring: 36T with BioCentric forward Q-Factor: 168mm

Shimano XT recommended 2x chainrings: 28/40T or lower

Shimano XTR 2x is not recommended. Both versions (40t/48.8mm chain line and 38t/46.6mm chain line) position the large chainring in a way that in may contact the frame

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Awesome bike! - Apr 02, 2014

1 2 3 4 5
5 out of 5 stars
MARQUETTE, MI

Finally went back to steel after riding aluminum and carbon bikes for years. I cant believe the ride of this thing! Super plush! Combine this frame with the Niner seatposts and its almost as if you were riding a fully suspended bike (without the weight, maintenance, or pedal feedback issues). I built this up as a single speed with American Classic Terrain wheels and Maxxis Ardents. XX1 Crank, Carbon seat post, XTR Race Brakes, Fox 32 Fork. Everything else is midgrade components. Bike weighs around 21.5 lbs. Still lighter than most full carbon full suspension race bikes that the pros ride. and a heck of a lot more durable. If I ditched the wheels and made a couple other upgrades, this bike would easy be in the sub 20 lb range. Also, built it as a 1x10 for a while, wieghed around 23 lbs. Biocentric II works great on this frame. No slipping or creaking. biggest complaint is that in order to adjust chain tension, I have to remove the non drive side XX1 crank to get at the bolts. This is not a problem with Shimano drive trains. Should have gone with full XTR ;)

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