Reactor Alloy 290
Reactor 290 Alloy Pro Eagle90 REA01AsM)
- S
- M
- L
- XL
- XXL
About Reactor Alloy 290
From concept to kinematics, geometry to spec, the Nukeproof Reactor was built from the ground up to be the ultimate aggressive trail bike. It climbs with precision but truly comes alive when you’re charging technical trails.
Constructed from a hydroformed and butted 6061 T6 aluminium alloy, with carbon fibre seat stays to reduce unsprung mass and optimise lateral stiffness. The Reactor delivers the perfect blend of low weight, strength, and stiffness.
Made for long days in the saddle, it’s your go-anywhere trail weapon—ready for epic adventures where a 1,000m climb leads to a 1,000m descent. Whatever the trail throws at you, the Reactor 290 Alloy is built to take it on.

Optimized Geometry and Suspension Kinematics
The Reactor Alloy is built around geometry that balances agility, stability and all day efficiency. A long, low and slack stance adds confidence on descents, while a steep seat tube angle places the rider centrally for precise handling and efficient power transfer on climbs. The four bar Horst Link platform delivers 140 mm of rear travel and is tuned to be supple off the top for traction and comfort, with strong mid stroke support that keeps the bike lively and responsive in technical terrain. As speed increases and you move down the cassette, anti squat reduces so the Reactor stays composed through rough sections and under braking, maintaining control and grip when it matters most. Combined with adaptable geometry via the Trail or Rail flip chip, the Reactor can shift from a nimble trail climber to a planted, confidence inspiring descender, a true all rounder ready to thrive wherever the trail leads.
Seamless trail shredding
Every detail of the Nukeproof Reactor is engineered to make life on and off the trail seamless. With rider focused practicality at its core, it combines performance with easy service. The front triangle accepts a full size 750 ml water bottle and an accessory mount under the top tube carries tools or spares, ideal for long self supported rides. Generous mud clearance for tyres up to 2.6 inches ensures reliability in harsh conditions, while MAX bearings throughout the frame deliver lasting smoothness and durability. Servicing is straightforward thanks to accessible hardware, sensible Allen key sizes and laser etched torque markings, complemented by tube in tube internal cable routing for a clean and rattle free setup. 3D contoured rubber guards protect key areas from impacts and chain noise. Thoughtfully engineered and trail proven, the Reactor is built to perform ride after ride.
Adaptability and frame construction
The Reactor Alloy balances toughness, precision and performance. It uses a 6061 T6 aluminium front triangle and chainstays for strength and reliability in aggressive trail riding, with a carbon fibre seatstay to fine tune responsiveness and vertical compliance. This hybrid layout gives a lively yet controlled feel on the trail, stiff and direct when pushing hard and smooth over rough terrain. Tubes and junctions are optimised for strength to weight, so the frame feels solid and dependable without losing agility. Built for everything from long mountain days to bike park laps, the Reactor Alloy combines practicality and performance for riders who demand versatility and durability in a single package. Adaptability is central to the design. A two position “Trail or Rail” flip chip lets riders refine geometry and handling. Trail mode provides an efficient balanced feel for big days, while Rail mode lowers the bottom bracket and relaxes the head angle for more aggressive descending and corner support. The Reactor V2 also offers wheel configuration options. The 290 Trail or Rail chip in the rear triangle can be switched to a 297 mix wheel Rail chip. Geometry and suspension kinematics match the 29 inch Rail setting, ensuring consistent performance across setups.
Specifications
Frame
Nukeproof Reactor V2 290 Alloy, 140mm Travel, custom triple butted hydro-formed tube set for front triangle and chain stays, UD woven carbon fibre Seat stays, internal cable routing, ISCG 05 mounts, Max Bearings, Threaded 73mm BB, Boost 148mm rear axMaterial
AluminiumBike Weight
15.17kg/33.4lbs (Tubeless)Fork
RockShox Lyrik Select +, Charger 3.1 RC2, 29" Boost 15x110mm Maxle Stealth, Debonair, 150mm, Gloss Black, 44mm OffsetRear Shock
RockShox Super Deluxe Select+ Air, 210x55mm, Bearing End, Custom Tuned with 1 Token, Rebound 55, Compression 30, 4x LockoutGroupset
Sram Eagle 90Rear Derailleur
Sram Eagle 90Crank
SRAM GX Eagle, 12-Speed, DUB, 165mm, 30T T-Type, 55mm CLCassette
Sram XS-1270 T-Type 10-52Brake Type
Post MountFront Brake
SRAM Maven Base, Organic padsRear Brake
SRAM Maven Base, Organic padsright_shifter
SRAM Eagle 90, 12-Speed MMXrotor
F: SRAM Centerline 2.0 180mm Rounded, R: SRAM Centerline 2.0 180mm Roundedchain
SRAM GX T-Type, 12-Speed Eagle, Flattop, PowerLock, 116 LinksWheelset
DT Swiss M1900 Spline. F: 29", 15x110mm Boost, R:29", HG Freehub, 148x12mm BoostOuter Tyre
F: Schwalbe Magic Mary Evo, Super Trail, TLE, 62-622 / 29x 2.4" Ultra Soft, R: Schwalbe Nobby Nic Evo, Super Trail, TLE, 62-622 / 29x 2.4" Softheadset
Nukeproof, 44-56 IITSHandlebar
Nukeproof Horizon V2 25mm Rise, Width - S/M780mm, L800mm, XL800mm, XXL800mmhandlebar_grips
Nukeproof Neutron Single Lock On, Diameter - NP1 - 29.6mm, NP2 & NP3 - 31.8mmStem
Nukeproof Neutron AM, 45mm, blackSeatpost
Tranz-X YS108 Internal with SRAM Remote lever, S:150mm drop; M:170mm drop; L:200mm drop; XL/XXL:230mm dropSaddle
Nukeproof Horizon SLRange
Trail/All-Mountain
Geometry
What is my size?| SMALL | MEDIUM | LARGE | X-LARGE | XX-LARGE | ||
|---|---|---|---|---|---|---|
| A | Reach | 435 | 460 | 480 | 500 | 520 |
| B | Stack | 620.24 | 629.26 | 638.29 | 647.31 | 656.34 |
| C | Effective Top Tube Length | 578.2 | 605.28 | 621.5 | 643.51 | 665.51 |
| D | Seattube Length | 380 | 410 | 440 | 470 | 500 |
| E | Effective Seattube Angle | Low 77° / High 77,5° | Low 77° / High 77,5° | Low 77° / High 78° | Low 77° / High 78° | Low 77° / High 78° |
| F | Seattube Angle (Actual) | Low 70.5° / High 71 | Low 70.5° / High 71 | Low 70.5° / High 71 | Low 70.5° / High 71 | Low 70.5° / High 71 |
| G | Saddle Height at Saddle Offset | 650 | 700 | 750 | 800 | 850 |
| H | Saddle Offset at Saddle Height | Low 146.4 High 146.6 | Low 164.4 High 163.4 | Low 174.2 High 172.9 | Low 191.8 High 189.5 | Low 209.4 High 206.2 |
| I | Headtube Length | 100 | 110 | 120 | 130 | 140 |
| J | Headtube Angle | Low 64.5° / High 65° | Low 64.5° / High 65° | Low 64.5° / High 65° | Low 64.5° / High 65° | Low 64.5° / High 65° |
| K | Chainstay Length | 440 | 440 | 445 | 445 | 445 |
| L | Front Centre | 758.8 | 788.07 | 812.38 | 836.68 | 860.99 |
| M | Wheelbase | 1198.8 | 1228.07 | 1257.38 | 1281.68 | 1305.99 |
| N | Bottom Bracket Drop (Front/Rear) | Low -39 / High -33 | Low -39 / High -33 | Low -39 / High -33 | Low -39 / High -33 | Low -39 / High -33 |
| O | Bottom Bracket Height | Low 330 / High 336 | Low 330 / High 336 | Low 330 / High 336 | Low 330 / High 336 | Low 330 / High 336 |
| P | Stand Over Height | 745 | 750 | 755 | 760 | 765 |
| Q | Fork Travel | 150 | 150 | 150 | 150 | 150 |
| R | Trail | 132 | 132 | 132 | 132 | 132 |
| S | Fork Offset | 42 | 42 | 42 | 42 | 42 |
| T | Axle to Crown | 561 | 561 | 561 | 561 | 561 |
| U | Maximum Seatpost Insert | 210 | 240 | 265 | 295 | 320 |
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