Niner ROS 9 review

Skinny steel big wheeler with full fat, full gas attitude

Our rating 
5.0 out of 5 star rating 5.0
GBP £849.00 RRP | AUD $1,490.00 | USD $900.00
Niner’s ROS 9 29er hardtail

Our review

Niner’s ROS 9 is definitely a niche bike, but if that’s your niche it’s perfect
Buy if, You’re prepared to invest in an addictively involving, effervescent premium price 29er for maximum singletrack flow without full suspension
Pros: Whippy steel smoothness, insane grip, neat single speed set up
Cons: Vague steering under load might not be for everyone
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There are a lot of really nicely made, aggressively angled, steel tubed hardtails around at the moment, some in 27.5, and some in 29er format, but nothing matches Niner’s ROS 9 for ridiculous rowdy rigid rear-end fun though.


At £849 for the frame, it’s at least twice the price of some equally nicely made alloy and steel frames. It’s still a bargain compared to most carbon frames though, and it’s absolutely drop dead gorgeous from its alloy cable cap inserts to its bullet shaped brake mounts.

It’s on the trail that the ROS 9 makes its difference felt, though, and it’s definitely a ride divider

The cunning externally clamping, eccentric bottom bracket lets you run a neat single speed set up or just change effect chainstay/front centre length and bottom bracket height by up to 17mm, or alter the effective seat angle too.

There’s a range of Niner cockpit, seating, MRP chainguide and wheels options, plus little gems like the ‘YouAreWhatYouDrink’ headset cap that lets you stick your chosen beer bottle top onto it. It’s exactly the richly indulgent, noticeably different experience you want from a boutique bike.

Ferrous freak

It’s on the trail that the ROS 9 makes its difference felt, though, and it’s definitely a ride divider.

For a start, if you like pin sharp accurate steering, then the very loose grip the skinny steel main tubes have on a 140mm fork will feel like using chop sticks for the first time. Being steel, the bike isn’t particularly light either (our build weighed 13kg / 28.6lb), and the skinny curved rear stays squeeze power onto the trail rather than stamping it through hard.


The level of compliance you get doesn’t just make it super comfy – it gives the 29er wheels insane levels of grip and impact absorbing speed sustain that many short travel suspension or plus tyre bikes would be proud of. Add the right flowing mindset and this is one of the most blisteringly quick, blissfully enjoyable technical singletrack machines we’ve ever ridden.

Product Specifications


Name ROS 9
Brand Niner

Description Geometry based on size Large
Available Sizes L M S XL
Seat Tube Angle 73
Head Tube Angle 67
Top Tube (cm) 61.7
Seat Tube (cm) 47.1
Chainstays (cm) 42.7
Wheelbase (cm) 114.4