With the introduction of the reborn Nukeproof Reactor, the brand has its first dedicated trail bike since the Nukeproof Mega TR back in 2015

Product Overview

Nukeproof Reactor 290 RS


Nukeproof Reactor 290 RS: first ride review


Price as reviewed:


With the introduction of the reborn Nukeproof Reactor, the brand has its first dedicated trail bike since the Nukeproof Mega TR back in  2015.

>>> Best full suspension mountain bike in 2019

The Nukeproof range has gone from strength to strength in the last few years, with the launch of a 29er Nukeproof Mega 290, and carbon versions of the popular, and EWS-winning, Nukeproof Mega 275 as well as a redesigned Nukeproo0f Scout hardtail. But a trail bike has been conspicuous by its absence.

Nukeproof Reactor need to know

  • New trail bike to sit below the popular Mega
  • Offered in 29in and 27.5in versions with either carbon or alloy frames
  • Alloy frames all get carbon seatstays
  • Flip chip lets you adjust head angle by 0.5° and BB height by 6mm
  • Room for a water bottle in the main triangle
  • Complete bikes from £2,499

The old Mega TR was a good bike at good price. Good enough, in fact, to win our £2k full-suspension group test back in Jan 2015 against the likes of Giant, Canyon and in-house rival Vitus.

nukeproof reactor

The original Nuke Proof Reactor. We’ve come a long way, baby!

Rather than stick with the TR label, Nukeproof has delved into the archive and resurrected the name of an old hardtail to pin on this thoroughly modern trail bike. There are subtle references to the past, but a firm grasp on the present, and it brings Nukeproof right back in the game. The old Reactor was sold in the nineties when Nuke Proof was two words, based in Michigan best known for its carbon/aluminium hubs. And while the new bike’s layout evokes memories of the early Mega, that’s where the similarities end.

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All sharp creases and angular details, the new Reactor looks sharp as a tack

With crisp carbon and manipulated aluminium frame options, the Reactor enjoys a razor sharp silhouette. The seatstays thrust upwards on a similar plane to the top tube – always a crowd pleaser – and there’s a smattering of elegant design details, such as the creased top tube, sharply tapered dropouts and seatstay bridge, and recessed swing link. Better still, they manage to enhance the overall look, and in the case of the latter, bring functional credibility by improving knee clearance, rather than being there simply to show off the designer’s repertoire.

nukeproof reactor

Compulsory flip chip gives half a degree of angle change and 6mm of ride height shift (production versions will have an arrow etched on the hardware pointing at Rail or Trail – this position is actually the steeper of the two)

The swing link drives a custom tuned RockShox Super Deluxe Ultimate RCT shock that worked perfectly with body weight, and Nukeproof has shrewdly specified a bearing (incidentally, all frame pivot bearings are now quality Enduro items) in the rear eyelet to reduce breakaway friction and improve small bump performance. And, the move pays off, as – true to the name – it’s an area in which the Reactor excels. I’ll elaborate on that in a minute.

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Shock bearing may be boring, but takes some beating

Boasting a genuine four-bar linkage, the Reactor 290 is packing 130mm of travel, with its smaller wheeled sibling gaining an extra 10mm. Up front, the suspension fork travel is 140mm and 150mm respectively, but the top-of-the-range RS model – ridden here – gains another 10mm on top of that.

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Geo chart – click to zoom

Nukeproof has played it safe without being overly conservative with the Reactor 290 geometry. There are three sizes to choose from, with reach measurements ranging from 446mm to 509mm on the XL. The size large has a reach of 475mm, which is identical to two of our Trail Bike of the Year contenders, and just a fraction longer than the winning YT Jeffsy 29. Compare some of the other vital stats and none of the numbers stand out as radical. One thing to note, however, is the RS model, ridden here has a slightly slacker head angle than the rest of the range, owing to the 10mm longer fork.

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The Reactor is also available in 275 wheel version

And if 29in wheels are not your cup of tea, the Reactor 275 is offered in four sizes, from S to XL, boasting a reach range from 420mm to 511mm.

Nukeproof Reactor review

The Reactor is a bad influence. It’s like the kid at school that broke the rules, threw stuff in class and held court behind the bike sheds, but always seemed to get away with it. This is a trail bike that prods you in the ribs and nags in your ear – loud and clear thanks to the effective rubber frame protection – screaming “faster, you chicken!” And, somehow, the bike lets you get away with it too. So, if you’re short of time and can’t be bothered to read the full review, that tells you all you need to know. If that’s left you intrigued, read on.

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The Reactor may only be a trail bike, but it’s never in danger of overheating

Usually, when a bike does this, it’s the geometry that’s making the biggest difference – taming the terrain and boosting your confidence. In the case of the Reactor the geometry certainly does its bit, but it’s the suspension that really lets you hang it out. Yes, there’s only 130mm of travel on the 29er, but Nukeproof has tuned the Reactor in such a way that you can exploit it all. As such it’s markedly sensitive off the top, generating fantastic levels of grip. To ensure this buttery response, Nukeproof has kept the anti-squat relatively low. Coupled with a slightly regressive leverage curve up to the sag point, and that low-friction bearing in the rear eyelet, means the shock is constantly working to track the ground on even the smallest ripple. The result? All that extra grip lets you turn harder, brake later and ride faster.

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The beautiful trails of Paganella bike resort in the Dolomites provided both flow and gnar in equal measures

‘Isn’t that just a recipe for poor pedalling performance and wasted energy on the climbs?’ I hear you cry. Not so. Nukeproof has pulled off a clever trick by giving the suspension freedom to move out of the way of bumps, but kept it in check when you want to put the power down. It’s done that partly by increasing the anti-squat in the lower gears, and partly by creating enough progression from the sag point to generate support. This is not just theoretical either; winching up steep inclines there’s impressive stability, and the bike never feels sluggish or inefficient powering out of turns.

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Sawtooth frame protection provides a silent ride

The seat tube is steep enough and the chainstays long enough to maintain good seated traction, and the weight balance between the wheels feels great on the size large. The only tweak we’d make to the sizing is to switch to a slightly shorter stem than the stock 50mm to make it easier to loft the front wheel.

So far, so glowing, but the Reactor is not without a couple of minor faults. With its longer travel fork, the bar height, BB height and head angle on the RS model feel spot on. Which suggests that the standard models, with their shorter forks, will be a touch on the steep side.

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Mavic Deemax DH wheels didn’t do the Reactor any favours, while the Assegai front tyre was outstanding

More significantly, the Mavic Deemax DH wheels on our test bike were distinctly twangy. For a downhill competition wheel, they flexed noticeably under hard cornering, snapping back rapidly as the load came off the rims in an unpredictable fashion. Examining the spoke pattern revealed that the bladed J-pull spokes weren’t laced under/over each other as we’d expect. After feedback from journalists and the team at Nukeproof, Mavic has made a change to the spoke lacing to rectify this issue, and we understand it has now been solved. Of course we still need to try them ourselves to be sure – something we hope to do very soon.


Wheels aside, the Reactor is a genuinely hot new trail bike. With handsome lines, versatile geometry that works in a wide range of terrain, lively, active suspension that still provides a stable pedalling platform and exciting, engaging handling, it ticks all the boxes and should be a strong contender for our 2020 Trail Bike of the Year title.


Frame:Carbon, 130mm travel
Shock:RockShox Super Deluxe Ultimate RCT
Fork:RockShox Lyrik Ultimate RCT3, 150mm travel
Wheels:Mavic Deemax DH wheels, Maxxis Assegai WT 3C/Minion DHR II 3C EXO 29x2.5/2.4in tyres
Drivetrain:SRAM X1 carbon 30t, SRAM X01 Eagle r-mech and shifter
Brakes:SRAM Code RSC, 180mm
Components:Nukeproof Horizon Carbon 780mm bar, Nukeproof Horizon stem 50mm, RockShox Reverb dropper post, Nukeproof Horizon SL saddle
Weight:14.46kg (31.9lb)
Sizes:M, L, XL
Size tested:L
Rider height:178cm
Head angle:65/65.5°
Effective seat angle:74.6/75.1°
BB height:330/336mm
Front centre:799mm
Top tube:641mm
Down tube:745mm