The Niner SIR 9 demonstrates steel is real! Steel bikes are as relevant today as they were 50 years ago. With that said, all steel is NOT created equal. The Niner SIR tubing is a custom selected set that utilizes the best tube options for each application within the frame. The front triangle is comprised of new Reynolds 853 DZB (Double Zone Butting) tubing. Developed for mountain bikes, more specifically 29ers, Reynolds 853 DZB offers two significant advantages. Historically downtube fork clearance on 29ers has been tricky because of the relatively high head tube to bottom bracket height. A straight downtube needs to be welded high on the back of the headtube to achieve fork clearance, often requiring either a gusset between the headtube and the downtube or a thicker heavier downtube to achieve the desired strength. The Reynolds 853 DZB tube overcomes this limitation by incorporating two different butting profiles on the same downtube. The superior strength is combined with a butting profile in the rest of the tube that maintains ride quality, and keeps the weight down. Secondly, the 853 DBZ tube is the proprietary bend. Niner worked with Reynolds to shape the tube for the SIR 9 so the tube can attach lower on the headtube, which reduces front end torsional flex, and increases steering precision and adds strength.
Like the rest of Niner's bikes, the SIR 9 utilizes Niner's tried and true geometry. There are plenty of nifty features that you’ll find in the SIR 9. The Niner SIR 9 features the BioCentric bottom bracket system. The BioCentric makes adjustment easy across a wide range of gears and eliminates the need for adjustable dropouts. The BioCentric offsets the bottom bracket spindle 8.5mm from center, offering greater range of adjustment compared to a more traditional EBB setup. Not to mention, the ultra flashy head badge and dazzing paint is enough to make you swoon.
- 73mm BB width (BioCentric installed)
- BioCentric is compatible with external bearing cranksets only. Crankset sold separately.
- 27.2mm seat post
- 28.6mm front derailleur, high mount, bottom pull
- 29.6mm seat collar size
- 1 1/8" headtube
- Small has one bottle mount in the front triangle. Medium through extra large have two bottle mounts inside the front triangle
- 135mm rear axle spacing
- Can fit up to 2.4” tire
- Compatible with standard 3x chainring systems
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