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Ltd Ed Nukeproof Reactor 290 ST is a short travel aggressive XC/Trail bike

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The Nukeproof Reactor ST is exactly that; a short travel version of the all-mountain Reactor, launched last summer. It is a limited edition build available only as a 29er. The ST boasts a lightweight XC build spec with 125mm of rear wheel travel and a 130mm travel fork. Taking the Reactor platform, Nukeproof aimed to build a mile-munching trail bike worthy of aspiring mountain goats, while also being a seriously capable machine for descents.

Photo by Winter Bike Connection – Rupert Fowler.

Note on the feature image: We caught up with Rob Sherratt from Nukeproof at the Winter Bike Connection event in Massa Marittima, Italy. He brought along a Reactor ST built in the image of the original Reactor of 1997, in celebration of Nukeproof’s 30th year. Sadly, it won’t be available in this red hot colorway. Photo by Winter Bike Connection – Rupert Fowler.

Nukeproof Reactor ST

Photo by Winter Bike Connection – Rupert Fowler.
  • Intended use: Aggressive XC/Trail
  • Suspension travel: 130mm/125mm
  • Wheel size: 29″
  • Sizing Options: M, L, XL
  • Frame: Carbon front and rear triangles
  • Claimed weight: 12.7kgs (28 lbs) in medium
  • RRP: Complete build £4,899.99
Photo by Winter Bike Connection – Rupert Fowler.

The Reactor ST loses 10mm fork travel and 5mm out back as compared to the factory Reactor 290. It retains the flip-chip at the seat stay-swing link interface allowing the rider to switch from TRAIL mode to RAIL mode. A 2-minute job with the use of a hex key alters the geometry from the ‘high’ position designed for maximum pedal efficiency, to the ‘low’ position, designed to maximise descending capability.

Photo by Winter Bike Connection – Rupert Fowler.

Short Travel Geometry

In TRAIL mode, the seat tube angle is a steep 76.8°. The 130mm travel fork sits at a 66.8° head angle. The BB drops 39mm to 330mm. Switching to TRAIL mode results in a slacker but still healthy 76.3° seat tube angle, a slacker 66.3° head angle and a lower BB height of 324mm. The chain stays are 440mm, consistent across the size range. Reach on the Reactor ST is a fair stretch longer than on the Factory Reactor 290c. In medium, reach is 460mm, increasing to 488mm in large, extending to 521.6mm in XL. All sizes feature a 51mm offset fork.

Photo by Winter Bike Connection – Rupert Fowler.

To ensure the Reactor ST climbs as well as it descends, Nukeproof designed the 4 bar horst linkage to have higher levels of anti-squat for the climbing gears but crucially lower levels as you drop down the cassette. This means that the bike should be an efficient climber but still offer the rider a lot of confidence on the descents.

Photo by Winter Bike Connection – Rupert Fowler.

Nukeproof say the combination of low anti-squat and a progressive suspension kinematic gives ultimate small bump compliance with good mid-stroke support for cornering/pumping. Anti-rise is engineered to allow the Reactor ST some squat when braking hard, maintaining rider position and providing sufficient pressure through the tire to ensure traction.

The geometry table is labelled “Mega 290 RS” but the figures pertain to the new Reactor ST

Availability: Limited

Photos by Winter Bike Connection – Rupert Fowler.

Only one build model of the Reactor ST will be available, at a price of £4,899.99. Be warned, this is a limited edition bike. The lightweight spec, worthy of an XC race bike, includes an XT 12-spd drivetrain with 30T chainring and 10-51 cassette. A DT Swiss 1501 wheelset is home to Maxxis Rekon tires. Suspension is serviced by a FOX Factory 34 fork with FIT4 damper, and a FOX DPS Factory shock. Completing the build is a RockShox Reverb Stealth dropper post and cockpit featuring Nukeproof’s premium Horizon components including a carbon bar and Sam Hill signature grips.


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4 years ago

Surprised at the weight for the build, honestly. I guess the alloy wheels don’t help.

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