The idea of 29+ tires may seem a little crazy, but Niner has never been one to toe the line. As the first full-line 29er manufacturer, going 29+ is a natural extension — allowing Niner to extend the big wheels to more riders and more riding conditions. After riding the new ROS 9 Plus, I’m still not sold on it being my only bike, but it certainly is fun!

Niner ROS 9 Plus 3-Star Features:

  • 4130 Chromoly frameset and fork for a classic feel
  • Slack head angle and short chainstays for a playful, capable ride
  • Fits up to 3.0 tires
  • Eccentric bottom bracket for singlespeed or geared
  • Full SRAM X1 groupset
  • Shimano Deore brakeset (180mm/160mm rotors)
  • Stan’s HUGO 29+ tubeless wheelset
  • Surly tires
  • Removable cable guides
  • Stealth dropper compatible
  • Niner aluminum cockpit (780mm bars, stem, seatpost)
  • Price: $2999
Niner ROS 9 Plus Review

The ROS 9 Plus is semi-fat and tons of fun.

Simple. Squishy. Fun.

While fatbikes are catching on in some areas, they are still niche or quiver bikes for those riders wanting a play toy or something to ride in the winter months. But, 29+ tires are more aimed at being your only bike, and I’d say it can certainly be that one bike, with some exceptions — read on to find out.

The 3-Star build is hung with a nice parts spec — highlighted by SRAM’s workhorse X1 11-speed component group. The hoops are Stan’s new HUGO 29+ and they are, of course, tubeless-ready. Niner delivers the ROS 9 Plus tubeless and I imagine most folks will gladly keep tubes out of the picture to save rolling weight and improve the steering/traction of this bike.

Niner ROS 9 Plus Review

Stand up and climb — this thing does it all.

Trademark Niner from head-to-toe

I’ve ridden fatbikes and found their performance to be lacking. Yeah, they are sure fun in the snow, but beyond that, they are really good at gathering dust. Would the 29+ tires prove to be more usable? The short answer is most certainly yes, but I’m not about to ditch my XC 29er.

Initially, I had the Surly Knard 3.0 tires inflated at about 12 psi — a little more than I would with a fatbike. This worked great for smoother trails and amplified the traction everywhere. It did make for sloppy handling due to tire roll, and, it exposed the HUGO rims to rocks when tackling more technical terrain.

Unfortunately, I dinged up the sidewall of the rim so bad on one ride that I completely lost air. Running tubeless, with no spare tube, I had to do the walk of shame. At home, I bent the sidewall back in place, pumped it up and it has held air perfectly ever since. Should you experience similar issues with your HUGO rims, your Niner dealer and/or Stan’s will take care of you.

After that incident, I increased tire pressure to 15 psi. in front and 18 psi. in the rear. That pressure made for a little faster rolling and, most importantly, kept me from dinging up the rims any further. For even rockier terrain, I’d up the pressure slightly, but I felt confident in the mostly-smooth terrain I’ve ridden since the aforementioned incident.

SRAM X1 Drivetrain on Niner ROS 9 Plus

SRAM X1 drivetrain shines.

Simplicity and fun-factor

Hopping on this bike reminds me of my fully rigid days of yesteryear. There’s something to be said about the simplicity of it all — no shock setup and a 1×11 drivetrain makes this modern bike feel simple. On the trails, it translates into a playful and fun bike. I particularly love hitting drops, rollers and jumps on this bike as it takes it all in stride and provides a consistent platform for getting airborne.

At slower speeds, the steering can be a little floppy, but it’s not too bad. At medium speeds, you’ll experience a fair bit of understeer. You have to pick your line deliberately and angulate into the turn to stick to that line. At higher speeds, understeer mostly disappears, but keep in mind that you will have to steer with a little more effort than you would with a regular-size set of tires.

As far as traction goes, yes, you’ll get more traction than a standard-sized tire, but don’t expect too much from these tires — they aren’t Velcro. You can push them to their limits and they will let loose on you, but they are supremely capable in all conditions. Something that is also nice about the big tires is the amazing braking traction. With such a large contact patch, braking is even more solid.

The ROS 9 Plus really is a ton of fun all over the mountain.

The ROS 9 Plus really is a ton of fun all over the mountain.

On climbs, you do have to find the right cadence to ascend bounce-free. At the proper cadence, you don’t bounce and you should be able to climb up just about anything in sight. Finding the right gear and cadence is critical. And, remember… you may not get there fast, but you’ll certainly get there fun.

Something that’s awesome about this bike is its ability to float confidently over loose terrain. I’m able to plow through loose gravel, sand and rocks without so much of a flinch — I love that! And, while the squish isn’t quite as good as suspension, it’s the next best thing and sure beats the heck out of riding a regular hardtail.

I haven’t experienced any issues with the SRAM X1 groupset and would certainly recommend going that route on any bike if you can’t justify the pricier and lighter XX1 group. I didn’t notice any difference in shifting performance and at the end of the day, your bank account will thank you.

Something to note about 29+ tires is they will fit in your current bike rack. I’ve been able to fit the ROS 9 Plus onto the RockyMounts BrassKnuckles and Yakima HoldUp without any issues — another reason why plus-size bikes are better than fatbikes.

Unfortunately, I didn’t have time to test out this bike in the snow as it came too late for proper snow adventures. I’m certain it will perform much better than a standard bike in the white stuff, but not quite as good as a full fatty. If you have had snow experience with this bike, chime in below.

The Good

  • Excellent traction, but it does have its limits
  • Simply rolls over everything in sight
  • Doesn’t get there fast, but it does get there fun
  • Simplicity of no suspension
  • SRAM X1 drivetrain doesn’t skip a beat
  • Go anywhere capability
  • Standard-width BB with normal Q-factor
  • It should fit on your current bike rack — hallelujah!

The Bad

  • Mild gyroscoping effect with steering
  • Bounce with me, bounce with me (at the wrong cadence)
  • Rim sidewalls can be damaged, but Stan’s will take care of you

The Bottom Line: Niner ROS 9 Plus

I’ll say it again, with the ROS 9 Plus, you may not get there fast, but you will certainly get there fun. No question… this is a fun bike to have and has proven much more versatile than a fatbike. It’s more nimble and really fun on dirt — plus, it will fit on your current bike rack.

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About Author

A native of the Pacific Northwest, Jason quickly developed a love for the outdoors and a thing for mountains. That infatuation continues as he founded this site in 1999 -- sharing his love of road biking, mountain biking, trail running and skiing. That passion is channeled into every article or gear review he writes. Utah's Wasatch Mountains are his playground.

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