Gear Stoke

Niner ROS 9 Custom Build

Niner ROS 9

Rollin’ With the Niner ROS 9

If the modern 6″ all-mountain enduro bike is to mountain biking what Black Sabbath was to music, than surely the steel single speed hardtail is the Muddy Waters of the sport. A raw and primal return to the roots and soul of trail riding. As such, I’ve been wanting to add a steel hardtail to the lineup. The rolling foothills of Park City’s lower elevation trail networks such as Glenwild & Round Valley are the perfect venue for such a machine. After purchasing the ROS 9 frame last fall, I slowly pieced together the parts throughout the winter until I had finally collected all the pieces necessary to complete the puzzle.

View Full Component Spec List

Niner ROS 9

Niner ROS 9

Starting with the frame which is a Niner ROS (roll over shit) 9. I knew I wanted a slack 29″ steel frame with clean, geometric lines and the ability to run it as a single speed out-of-the-box. From what I read prior to purchasing, Niner built the ROS 9 with an emphasis on fun. As a steel bike, it’s guaranteed not to be the lightest out there, and with a 67.5 degree head-angle + beefy 130mm fork combo, it’s certainly not as sprightly on the ascents as other bikes in it’s class. However, I’ve always approached bike buying with fun over fast in mind, and the ROS 9 seemed to fit the bill for my criteria perfectly.

Niner ROS 9

I’ve been running the MRP Stage on my trail bike for the past year or so, and couldn’t be more pleased with the results. Naturally, the Stage 29 seemed like the obvious choice given the ROS 9’s lineage as a roller-over and buster-througher of shit. Overkill for a hardtail 29er… probably, but who cares.

ROS 9 High Roller II

For socks and shoes I paired the Easton Haven’s with Maxxis High Roller II’s – again, the same combo I’m running on the trail bike. In terms of an all-mountain trail tire, I’ve yet to find rubber I like better than the High Roller. Eventually I’d like to get a pair of 27.5+ wheels that I can swap out for adventure rides.

Niner ROS 9

The drive-train is made up of XT cranks mounted to a 32t Wolf Tooth Components Drop-Stop Eliptical Ring up front with a Woolftooth 19t cog in back, and Time ATAC MX-4 pedals. I may have bitten off more than I can chew with a 32×19 ratio, so we’ll see how long before I swap out for a 20t or 21t. So far I’m digging the oval ring, however, I’d like to get a traditional circle ring so I can make a more direct comparison.

Chromag Trailmaster Saddle

Two of my favorite touches on the bike are the Chromag Trailmaster leather saddle and the frame’s internal dropper-post routing for the Reverb Stealth dropper. I would long give up a rear shock over a dropper-post, so it’s nice to see brands like Niner taking these details into consideration on their frames. It’s these little touches that separate brands like Niner from the rest of the pack.

Ergon Grips

Part of the beauty of a single speed is that it allows for a clean and minimal cockpit. This bike comes with two speeds – sit down & stand up. Additionally, after riding with Ergon’s shaped grips for some time now, anything else just doesn’t feel right anymore, so I went with the GE-1’s slipped over Easton Haven bars all held together with a Renthal Duo stem.

Pedal Damn It

Pedal damn it.

Niner ROS 9

Niner ROS 9

Niner ROS 9

Niner ROS 9


Wolftooth Drop Stop Eliptical Ring

Wolftooth Singlespeed Cog

Niner ROS 9

Niner ROS 9 Build Component Spec

About the author


Alex is a designer by trade & mid-grade adventurer by night who’s quite partial to knobby tired bikes, clean design, & dirty hands. When not updating this silly website, he's likely off exploring the nearby hills with a few of his favorite partners in crime.


  • So where’s the review? Or is this site just for looking at bikes and talking about what components we put on them? Kind of anticlimactic.

    • Wow… someone certainly has their panties in a bunch. The post is titled “Niner ROS 9 Custom Build” so yes, it is simply about looking at the bike and components spec. I don’t know about you, but it takes more than a ride or two to get to know a bike well enough to review it. Review will be coming soon, so check back, or don’t, I really don’t care as you sound like a real bundle of joy… PS: If you’re looking for climax, maybe go ride the bike yourself.

      • I am a bundle of joy, it’s just a well-salted bundle. I’ll keep an eye out for the review, I’m very interested in this bike. How do you like it so far? Your setup looks pretty sweet.

  • Great looking build. I have one on order and I am on the fence wether to build it SS or geared. What does your build weigh?

    • Hi Eric,

      No idea what the exact weight is, but it’s by no means light! Prob in the 28-30 lb range…

      In regards to the gearing, I love SS riding, however, I’m prob going to put some gears on it in the spring. Singlespeeding up and down mountains is just too much for my knees to handle – however, if you’re riding somewhere w/out much elevation change go for it!

      Thanks for reading!

  • Sweet hardtail, love my steel frame Honzo.

    Not sure if I like the bike more then seeing that it comes with Time Atac pedals, by far the best pedals especially if your ride anywhere in the PNW, you can always clip in

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