On This Page
Build Overview
This project started as another one of our “bikes we ride” experiments—taking bikes we already own, moving parts around, and seeing what interesting combinations we can come up with. This one uses a previous-generation Niner RKT 9 RDO full-suspension XC frame and converts it into a drop-bar monster-cross style gravel bike.
We’ve done this concept before with Lynn’s Niner Air 9 hardtail, and because SRAM AXS components communicate wirelessly across road and mountain groups, it’s incredibly easy to build a drop-bar setup around a mountain drivetrain. This RKT has been one of our favorite XC bikes, and with leftover parts from other builds and a little creativity, it made a perfect candidate to convert.
Video
Full Build Specs
- Frame: Niner RKT 9 RDO (previous-generation)
- Fork: Fox 32 (120mm travel)
- Drivetrain: SRAM AXS — Force road shifters paired with XX1 Eagle AXS rear derailleur
- Rear Derailleur: SRAM XX1 Eagle AXS
- Cassette: SRAM GX Eagle
- Crankset: SRAM Force Wide road crank
- Chainring: 36T (with previous testing using 42T)
- Bottom Bracket: SRAM DUB with mixed spacers for chainline correction
- Handlebar: Easton AX aluminum drop bar
- Stem: Currently 70mm (likely moving to 60mm)
- Seatpost: Niner carbon seatpost
- Saddle: Prologo
- Wheels: Reserve 28 XC with DT Swiss 350 hubs (from a ZFS build)
- Tires: Current: MTB tires shown.
Previous setups: Vittoria Mezcal/Barzo combos for gravel. - Weight: ~26 lbs 6 oz (with pedals)
Build Notes
This RKT 9 RDO originally came as a 3-Star GX mechanical build with either Stan’s or DT wheels. Like many bikes over the past few years, upgrade kits made it cheap and easy to convert to AXS wireless shifting. That upgrade opened the door for fun experiments—like converting an XC race bike into a drop-bar gravel bike.
Because this is the previous-generation RKT, the brake line runs externally along the frame, making bar swaps extremely quick. The drop-bar setup (levers, brakes, and calipers) came directly off the Air 9 drop-bar project, already connected and ready to bolt on. We can now switch this bike between flat bars and drop bars in about 20 minutes.
The drivetrain uses a mix of SRAM’s ecosystems: Force AXS road shifters paired with an XX1 Eagle AXS rear derailleur and a GX Eagle cassette. The crank is a Force Wide road crank that fits the frame with only minor spacing adjustments. We’ve tested 42T and 36T rings—42T works better for fast gravel, while 36T is ideal for rowdy singletrack and technical riding.
The wheels are Reserve 28 XC on DT350 hubs—brought over from a ZFS XC build. Paired with the carbon Niner post and a Prologo saddle, the bike ends up surprisingly comfortable. Fit-wise, this is a Medium frame, and while it worked great with 70–80mm stems as a flat-bar XC bike, the drop-bar version feels better with a slightly shorter stem. We’ll likely settle around 60mm.
Riding impressions are interesting: with flat bars, the bike feels snappy and agile—exactly what you’d expect from a full-suspension XC bike. But the moment you put drop bars on it, your brain switches to “gravel mode,” and it feels different, even though it’s the same bike. It accelerates a bit slower, but once rolling it’s incredibly smooth. You can hit washboard and chattery gravel and barely feel it—this setup absolutely eats that stuff.
Overall, this has been a fun project and a great example of how flexible AXS systems and modern MTB frames can be. We’re always tinkering, and builds like this keep things interesting around the shop. If you want something unique or need a bike built for a very specific purpose, we’d love to help you put it together.
Photo Gallery
[Add your WordPress gallery block here]
Work With Us On a Custom Build
If you’re thinking about a custom gravel, MTB, or road build, we can help you spec it out, match the components to your riding style, and build it right.