At a time when carbon super bikes (including our own 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, when we get on a steel frame, are we instantly transported back to that first bike we 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 our 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 SIR 9 – all the fun, all the advantages, all the steel.
NEW TUBESET WITH AWARD WINNING NINER GEOMETRY
All steel is not created equal. The SIR 9 tubing is a custom-selected set that utilizes the best tube options for each application within the frame.
For the front triangle, we employ the new Reynolds 853 DZB (Double Zone Butting) tubing. Developed for mountain bikes, and specifically 29ers, Reynolds 853 DZB offers two significant advantages:
Downtube fork clearance in 29ers is tricky because of the relatively high HT-to-BB 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 desired strength. The Reynolds 853 DZB tube overcomes these limitations by incorporating two different butting profiles on the same downtube– extra strength at the headtube combines with a butting profile in the rest of the tube that maintains ride quality and avoids weight penalties – strong where we need it, compliant where we want it.
Another advantage and a significant first for this 853 DBZ tube is the proprietary bend. We worked with Reynolds to shape this tube for the SIR 9 so the tube can attach lower on the headtube, reducing front end torsional flex, increasing steering precision and adding strength.
For the stays, we 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, provides superior power transfer while preserving the compliant ride quality you want in a steel frame.
When combined with Niner’s hardtail geometry expertise, the result is a new frame that is sure to win as many Rider’s Choice awards and great reviews as has the first SIR 9.
The new SIR 9 is now able to utilize tapered (or 1-1/8") steertube fork technology. The increased surface area of a tapered headtube allows for a larger downtube, increasing strength and rigidity at this critical intersection. Tapered fork steerer tubes measurably reduce fork deflection, which means your Niner tracks straight and true. The full spectrum of riders from XC racers to All Mountain shredders benefit from these features which is why we incorporate the technology in all our new frames. The SIR 9 lets you take full advantage of increased steering precision as you carve a corner and descend toward the finish.
BIOCENTRIC II BOTTOM BRACKET SYSTEM
The Niner BioCentric II makes adjustments easy across a wide range of gears and eliminates the need for adjustable dropouts, giving the cleanest possible solution for singlespeed use. No bolt on hubs, no chain tensioner cluttering your ride, no brake adjustments with gear changes.
Greater Range - The BioCentric II offsets the bottom bracket spindle 8.5mm from center, offering greater range of adjustment compared to a more traditional EBB setup. More offset is a boon when changing gears without having to change chain length and it allows riders to make more noticeable changes to frame geometry via BB position.
Reliable Function - Traditional EBB units are held in place with set screws that can become difficult to finely adjust over time, or expansion wedges that can deform the bottom bracket shell of the frame. Split BB shells that clamp an EBB can stretch or ovalize. The BioCentric II avoids these troubles by using two bolts to apply a clamping force on the outside edges of the BB shell, eliminating the possibility of ovalizing or indexing the shell itself. Field tested for over 18 months and 7000 miles, secure, quiet, easy to install and adjust, the BioCentric II will change your ideas about singlespeed drivetrain setup and maintenance.
ATTENTION TO DETAIL
While tubing upgrades are the focus of this new design, we haven’t forgotten the details. The new the SIR 9 uses 142x12 spacing with an included maxle for added rear-end torsional stiffness, post mount brake bosses between the chain and seatstay for braking precision, and, of course, the Niner headbadge and two great color options for that finishing touch.