In last year’s Best Trail Bike of 2020 group test, the Nukeproof Reactor 290C RS with its extra-long travel fork missed out on our coveted Best in Test title by a hair’s breadth. This year, the Brits enter the race with the Reactor Factory build, which should offer better all-round qualities. But can this model with slightly less travel convince on climbs and flowing trails?

For an overview of the test fleet head to the group test: The best mountainbike of 2021 – 22 models in review

Nukeproof Reactor 290C Factory | 140/130 mm (f/r)
14.7 kg (size L) | € 6,155 | Manufacturer-website

The Nukeproof Reactor 290C is an old acquaintance. This year, the Brits enter the race with the 140 mm Reactor 290C Factory model, which has 10 mm less travel up front than the RS version we tested last year. The frame details of the 14.7 kg Reactor 290C attest to the brand’s clear focus on downhill performance. The smooth lines and harmonious olive-green finish with golden decals are eye-catching, while the extensive frame protector that comes as standard with the Reactor 290C Factory should set an example for all other brands in the test. Even after weeks of constant abuse, our test bike looks as fresh as it did on day one – very impressive. Just as impressive is the generous seat- and chainstay protector, which was designed to reduce chain slap. That being said, the Reactor isn’t completely quiet: the internally routed cables aren’t clamped at the entrance point, making a loud rattling noise on rough descents and the cable routing under the bottom bracket isn’t ideal either. Unlike other Nukeproof models, for example, the Mega and Giga, the Reactor doesn’t feature an accessories mount on the top tube, though there is enough room in the frame for a large drinking bottle.

We wouldn’t have specced the Nukeproof Reactor 290C Factory any differently

Spot on! We wouldn’t have specced the € 6,155 Reactor Factory any differently. Why? Because Nukeproof have prioritised downhill performance and robust components over an excessively lightweight build. One of the highlights of this powerful build is the FOX Factory suspension with a 36 GRIP2 fork and DPX2 shock, controlling 140 and 130 mm of travel respectively. Shifting and braking are taken care of by a Shimano XT groupset made up of a 12-speed drivetrain and four-piston brakes, combined with a 200 mm rotor at the front and 180 mm disc out back. The BikeYoke Divine dropper post, which comes with 160 mm of travel on frame sizes M/L and 185 mm on the biggest XL frame, is operated by a Shimano remote, ensuring good ergonomics and a tidy cockpit. The latter consists of Nukeproof’s own components including a wide 800 mm alloy handlebar. In combination with the excellent damping qualities of the Sam Hill Signature grips, the cockpit filters out high-frequency vibrations, reducing fatigue and arm pump on long descents. For the sake of reliability, Nukeproof chose a DT Swiss XM1700 alloy wheelset over a lighter carbon model – very cool! The Reactor rolls out of the factory on MAXXIS tires with the puncture prone EXO+ casing and medium-hard 3C MaxxTerra compound, with an ASSEGAI at the front and DISSECTOR outback.

Trail performance over light weight. To do justice to the potential of the Reactor, Nukeproof deliberately choose robust alloy components over carbon bling. Cool!

The only flaw in the spec
The Reactor comes without a chain guide. Given the trails and the speed the bike is capable of, we recommend retrofitting a minimalist model.
Excellent fork
Two years ago, the FOX 36 was the measure of all things for potent, rowdy bikes. The Reactor proves that the 36 GRIP2 Factory delivers an outstanding performance even with less travel.
How did they do it?
The rear end of the Reactor is phenomenal. In addition to the bearings in the lower shock mount, Nukeproof must have done some black magic to the kinematics.

Nukeproof Reactor 290C Factory

€ 6,155


Fork FOX 36 Factory GRIP2 140 mm
Rear Shock FOX DPX2 Factory 130 mm
Seatpost BikeYoke DIVINE 160 mm
Brakes Shimano XT M8120 200/180 mm
Drivetrain Shimano XT 1x12
Stem Nukeproof Horizon 50 mm
Handlebar Nukeproof Horizon 800 mm
Wheelset DT Swiss XM1700 30 29"

Technical Data

Size M L XL
Weight 14.7 kg

Rail that turn
The geometry of the Reactor can be adjusted with a flip-chip in the seat stay. We prefer the deep “Rail” setting, which lowers the bottom bracket and slackens the head angle, making the Nukeproof a real corner ripper.
The frame is made from carbon, everything else is alloy
Nukeproof deliberately chose to use a high-quality DT Swiss XM1700 alloy wheelset which, compared to many carbon rims, holds up even with thin-walled tires. Cool!
Stiffer isn’t always better
While at first glance the alloy cockpit with 31.8 mm might look a little outdated, it was chosen deliberately for the sake of comfort. On long descents, it filters vibrations and thus prevents arm pump.

The geometry of the Nukeproof Reactor 290C

Unfortunately, shorter riders could walk away empty handed with the Nukeproof Reactor 290 and have to settle for the Reactor 275, which has more travel, a slightly different frame and 27.5” wheels. That’s because the 29” version is only available in three sizes: M, L and XL. With a reach of 480 mm (size L) and 440 mm chainstays, the geometry of the Reactor is nicely balanced and not too extreme. The 75° seat angle makes for a very comfortable riding position without pushing the rider too far back over the rear wheel. As a result, the pedalling position is comfortable on long rides and yet central enough to tackle steep climbs. A flip-chip in the seat stay allows you to adjust the geometry of the Reactor by 0.5° – we prefer the low “Rail” setting.

Size M L XL
Seat tube 420 mm 458 mm 508 mm
Top tube 610 mm 640 mm 675 mm
Head tube 105 mm 110 mm 115 mm
Head angle 65.5° 65.5° 65.5°
Seat angle 75.5° 75.5° 75.5°
Chainstays 440 mm 440 mm 440 mm
BB Drop 39 mm 39 mm 39 mm
Wheelbase 1,205 mm 1,235 mm 1,271 mm
Reach 451 mm 480 mm 514 mm
Stack 615 mm 620 mm 625 mm
Helmet Fox Speedframe | Glasses 100% Speedcraft | Hippack AMPLIFI Hipster4
Shirt Fox Ranger Jersey | Pants Fox Flexair | Kneepads AMPLIFI MKX
Shoes Five Ten Kestrel Lace MTB SPD | Socks Stance

What a blast! The Nukeproof Reactor 290C Factory on the trail

Regardless of which setting you run, we recommend activating the climb switch on long climbs. With the shock fully open, the suspension tends to bob and can’t keep up with more efficient bikes like the Canyon Spectral or Rocky Mountain Instinct – what a pity! The Nukeproof prefers to get to the trailhead in relaxed fashion on easy forest paths.

Uphill, the Nukeproof Reactor lacks liveliness. While downhill it rides at the front of the pack, uphill it’s simply not efficient enough to be a perfect all-rounder.

Tuning-Tipps: minimalistische Kettenführung | Züge an den Eingängen klemmen

Downhill, the Reactor makes up for its middling climbing performance, punching well above its travel class as soon as gravity takes over! We can’t get our heads around how Nukeproof managed to squeeze this much traction and reserves into the 130 mm rear end. Despite the low-profile tread of the rear tire, the Reactor is hungry for speed and overtakes most of its competitors on the inside-line through corners. The weight is always perfectly distributed between the front and rear wheel, ensuring composed yet lively handling and conveying huge amounts of confidence. No other bike on test changes direction as quickly, willingly, intuitively and safely as the super balanced Nukeproof Reactor 290C Factory! Only on very flat trails is the Nukeproof unable to keep up with the liveliest bikes, like the Yeti SB115, where it requires more strength to pump through the trail and pull off ledges. Nevertheless, the Reactor Factory will easily get you through a day of intense enduro riding: the suspension swallows up huck-to-flats just as eagerly as it irons out nasty rock gardens, delivering tons of fun while feeling composed and safe at all times.

Riding Characteristics



  1. sluggish
  2. efficient


  1. cumbersome
  2. playful


  1. nervous
  2. confident


  1. demanding
  2. balanced


  1. harsh
  2. plush

Fun Factor

  1. planted
  2. poppy

Value for money

  1. terrible
  2. very good

Intended Use










The Nukeproof Reactor 290C Factory proves that the amount of travel alone says very little about the downhill capabilities of a bike: despite having just 130 mm rear travel, we would happily take the Nukeproof to some enduro races! Downhill, the Reactor is hungry for speed, with the balanced handling making it a great and fun option for experienced racers and mountain bike newbies alike. It shakes up the perfect cocktail of liveliness and composure and offers top riding fun on all sorts of trails. However, uphill it lacks the liveliness and efficiency a true all-rounder needs. That’s a real shame because the elegant carbon frame and well-thought-out spec are spot-on!


  • well thought-out spec suits the intended purpose
  • intuitive, balanced handling
  • good suspension
  • comfortable pedalling position for long rides


  • climbing efficiency

Find more information her:

The testfield

Get an overview of the grouptest here: The best mountainbike of 2021 – 22 models in review

All Bikes in this group test: Canyon Neuron CF SLX 9 (Click for review) | Canyon Spectral 29 LTD (Click for review) | Canyon Stoic 4 (Click for review) | FOCUS THRON 6.9 (Click for review) | Ibis Ripmo V2 (Click for review) | MERIDA eONE-SIXTY 10K (Click for review) | MERIDA NINETY-SIX 8000 (Click for review) | Nukeproof Reactor 290C | Orbea Rise M-Team (Click for review) | Propain Hugene (Click for review) | RAAW Jibb XTR Build (Click for review) | Rocky Mountain Instinct C70 (Click for review) | Santa Cruz 5010 X01 (Click for review) | Santa Cruz Tallboy CC X01 (Click for review) | SCOTT Ransom 900 Tuned AXS (Click for review) | Specialized S-Works Stumpjumper (Click for review) | Specialized S-Works Stumpjumper EVO (Click for review) | Specialized S-Works Turbo Levo SL (Click for review) | Trek Fuel EX 9.8 GX (Click for review) | Trek Top Fuel 9.9 X01 (Click for review) | Yeti SB115 TURQ3 (Click for review) | YT IZZO BLAZE 29 (Click for review)

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Words: Photos: various