The Nukeproof Reactor 275 Alloy Comp: One Bike to do it all
A trail bike that thrives in technical terrain — both up and down. It’s the ultimate option for the rider looking for one bike to do it all.
From concept to design, the Reactor 275 Alloy is built from the ground up to be the ultimate aggressive trail bike. It’s an uncompromising build with an alloy frame and nimble 27.5-inch wheels for maximum playfulness and fun. Specced with a build that leans towards aggressive descending but with kinematics and geometry efficient enough to pedal big miles, it’s a go-anywhere and do-anything machine.
It’s a bike built for all-day epics in backcountry terrain — where a 2,000-foot climb will inevitably lead to a 2,000-foot descent and you need a bike that’ll handle both equally well.
How it Rides
The Reactor was built from the Nukeproof staff’s desire for a quiver-killer mountain bike that climbs well and descends without compromise.
Designed to be poppy, playful and wicked fast, the Reactor’s four-bar Horst link suspension system is supportive while climbing but an absolute hooligan on the descent. Solid mid-stroke support balanced with relatively modest anti-squat gives the Reactor an active rear end that’s shockingly supportive and efficient when pedaling uphill. Anti-squat reduces as you shift down the cassette and pick up speed, making the bike come alive on descents. Balanced anti-rise figures allow the Reactor some squat when braking hard, maintaining rider position and providing a good amount of pressure through the tire to ensure traction.
To optimize weight, strength and stiffness, the Reactor 275 Alloy’s frame is made of triple-butted 6061 aluminum alloy with seatstays molded from carbon fiber. We tailor the geometry based on wheel size, so this 275 version of the bike is optimized to take full advantage of the poppy and playful nature of the smaller wheels.
All Reactor frames also feature a “flip chip,” which allows you to adjust the geometry from “Trail” to “Rail” mode. Trail balances optimized geometry for climbing and descending while the Rail mode emphasizes the downhill — dropping the bottom bracket 6mm and slackening the head tube angle by half a degree.
Whatever you’re in to, the Reactor will do it.
The Nukeproof Reactor 275 Alloy Comp Component Details
- Marzocchi Bomber Z2 fork & RockShox Super Deluxe Select R shock
- Shimano Deore 12-speed drivetrain
- Shimano Deore or SRAM DB8 4-piston brakes
- Sun-Ringle Duroc 35 Comp 27.5-inch tubeless wheels
- Maxxis Assegai front tire & Dissector rear tire
Full Specs
Comp | Pro | Frame Only | |
---|---|---|---|
Frame | Nukeproof Reactor 275 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, internal cable routing, ISCG 05 mount, Enduro bearings, threaded 73mm BB, Boost 148mm rear axle spacing, 3D contoured rubber frame protection. | Nukeproof Reactor 275 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, internal cable routing, ISCG 05 mount, Enduro bearings, threaded 73mm BB, Boost 148mm rear axle spacing, 3D contoured rubber frame protection. | Nukeproof Reactor 275 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, internal cable routing, ISCG 05 mount, Enduro bearings, threaded 73mm BB, Boost 148mm rear axle spacing, 3D contoured rubber frame protection. |
Fork | Marzocchi Bomber Z2, 150mm, 44mm Offset, BOOST, RAIL Damper, Gloss Black | RockShox Lyrik Select + Charger 2.1 RC 160mm, 46mm Offset, BOOST, Debonair, Gloss Black | |
Shock | RockShox Super Deluxe Select R, Custom Compression LIN, Rebound L 320 tune, 210x55mm, Bearing End, 1x bottomless token fitted. | RockShox Super Deluxe Select+ RT, Custom Compression LIN, Rebound L 320 tune, 210x55mm, Bearing End, 1x bottomless token fitted. | RockShox Super Deluxe Ultimate RCT, Custom Compression LIN, Rebound L 320 tune, 210x55mm, Bearing End, 1x bottomless token fitted |
Front Wheel | Sun-Ringle Duroc 35 Comp 27.5", 15x110mm | Nukeproof Neutron V2 27.5", Tubeless Ready, 32h, 110x15mm | |
Rear Wheel | Sun-Ringle Duroc 35 Comp 27.5", Shimano Microspline Driver, 148x12mm | Nukeproof Neutron V2 27.5", Tubeless Ready, 32h, SRAM XD Driver with 36 points of engagement, 148x12mm | |
Tyres | Front: Maxxis Assegai 27.5”x2.5 WT 3C MaxxTerra/EXO+/TR, Rear: Maxxis Dissector 27.5”x2.4 WT 3C MaxxTerra/EXO+/TR | Front: Maxxis Assegai 27.5”x2.5 WT 3C MaxxTerra/EXO+/TR, Rear: Maxxis Dissector 27.5”x2.4 WT 3C MaxxTerra/EXO+/TR | |
Crankset | Race Face Ride, 12 Speed Crank, 170mm, 32T, 52mm Chainline | SRAM GX Eagle 12-Speed, 170mm, 32T, B148, DUB | |
Shifter | Shimano Deore M6100-IR, 12-speed Rapidfire Plus, I-Spec EV | SRAM GX Eagle 12-Speed | |
Rear Deraileur | Shimano Deore M6100, SGS 12-Speed, Shadow Plus | SRAM GX Eagle 12-Speed | |
Chain | Shimano Deore M6100 12-Speed | SRAM GX Eagle 12-Speed | |
Cassette | Shimano Deore M6100 12-Speed (HYPERGLIDE+), 10-51T | SRAM GX Eagle 12-Speed, CS XG1275 EAGLE 10-52T | |
Brakes | Shimano M6120 or SRAM DB8 | SRAM Guide RE | |
Front Rotor | 203mm | SRAM Centreline, 200mm | |
Rear Rotor | 180mm | SRAM Centreline, 180mm | |
Handlebars | Nukeproof Neutron V2 25mm Rise, Width - S780mm, M780mm, L800mm, XL800mm | Nukeproof Horizon V2 25mm Rise, Width - S780mm, M780mm, L800mm, XL800mm | |
Stem | Nukeproof Neutron AM, 45mm, black | Nukeproof Neutron AM, 45mm, black | |
Saddle | Nukeproof | Nukeproof | |
Seatpost | Brand-X Ascend internal, 31.6mm, S:125mm drop; M:150mm drop; L:170mm drop; XL:200mm drop | Brand-X Ascend internal, 31.6mm, S:125mm drop; M:150mm drop; L: 170mm; XL:200mm drop | |
Headset | Nukeproof, 44-56 IITS | Nukeproof, 44-56 IITS | Nukeproof, 44-56 IITS |
Grips | Nukeproof Sam Hill Signature | Nukeproof Sam Hill Signature | |
Bearings | Enduro Bearings | Enduro Bearings | Enduro Bearings |
Weight:(Size Medium) | 14.84kg (Tubeless) | 14.51kg (Tubeless) | 3.77Kgs/8.3lbs (Medium) |
Geometry & Sizing
Reactor 275 150mm Fork (Alloy) | Reactor 275 160mm Fork (Alloy) | |||||||
---|---|---|---|---|---|---|---|---|
Small | Medium | Large | X-Large | Small | Medium | Large | X-Large | |
(A) Reach | 425 | 454 | 482.5 | 516 | 420.2 | 449.5 | 478 | 511.5 |
(B) Stack | 600 | 605 | 609 | 613.5 | 603 | 608.5 | 612.5 | 617.3 |
(C) Effective Top Tube Length | 580 | 610 | 640 | 675 | 581 | 611.2 | 641.5 | 676.3 |
(D) Seattube Length | 381 | 420 | 458 | 508 | 381 | 420 | 458 | 508 |
(E) Effective Seattube Angle | 75.5° (Low 75°) |
75.5° (Low 75°) |
75.5° (Low 75°) |
75.5° (Low 75°) |
75.1° (Low 74.6°) |
75.1° (Low 74.6°) |
75.1° (Low 74.6°) |
75.1° (Low 74.6°) |
(F) Seattube Angle (Actual) | 71° (Low 70.5°) |
71° (Low 70.5°) |
71° (Low 70.5°) |
71° (Low 70.5°) |
70.6° (Low 70.1°) |
70.6° (Low 70.1°) |
70.6° (Low 70.1°) |
70.6° (Low 70.1°) |
(G) Saddle Height at Saddle Offset | ||||||||
(H) Saddle Offset at Saddle Height | ||||||||
(I) Headtube Length | 110 | 115 | 120 | 125 | 110 | 115 | 120 | 125 |
(J) Headtube Angle | 66° (Low 65.5) |
66° (Low 65.5) |
66° (Low 65.5) |
66° (Low 65.5) |
65.5° (Low 65) |
65.5° (Low 65) |
65.5° (Low 65) |
65.5° (Low 65) |
(K) Chainstay Length | 430 | 430 | 430 | 430 | 430 | 430 | 430 | 430 |
(L) Front Centre | 728 | 759 | 790 | 825 | 732 | 763 | 794 | 829 |
(M) Wheelbase | 1150 | 1181 | 1212 | 1247 | 1154 | 1185 | 1216 | 1251 |
(N) Bottom Bracket Drop | -18 (Low -24) |
-18 (Low -24) |
-18 (Low -24) |
-18 (Low -24) |
-15 (Low -21) |
-15 (Low -21) |
-15 (Low -21) |
-15 (Low -21) |
(O) Bottom Bracket Height | 336 (Low 330) |
336 (Low 330) |
336 (Low 330) |
336 (Low 330) |
339 (Low 333) |
339 (Low 333) |
339 (Low 333) |
339 (Low 333) |
(P) Stand Over Height | 723 (High) | 721 (High) | 722 (High) | 725 (High) | 729 (High) | 728 (High) | 729 (High) | 732 (High) |
(Q) Fork Travel | 150 | 150 | 150 | 150 | 160 | 160 | 160 | 160 |
(R) Trail | ||||||||
(S) Fork Offset | 46 | 46 | 46 | 46 | 46 | 46 | 46 | 46 |
(T) Axle to Crown | 545 | 545 | 545 | 545 | 555 | 555 | 555 | 555 |
(U) Maximum Seatpost Insert | 175 | 215 | 250 | 300 | 175 | 215 | 250 | 300 |
*All dimensions in mm unless otherwise stated
Recommended Sizing


Help
- FAQs
- Frame Spec
- Industry Reviews
- Tech Docs
- Where can I buy Nukeproof Bikes?
- Nukeproof bikes, components and apparel is sold through an authorised dealer network. Check out our dealer locator for your local local stockist or preferred online store www.nukeproof.com/dealers.
- Do your bikes come with Warranty?
- All Reactor frames come with a 5 year frame warranty (Please visit www.nukeproof.com/warranty for full info). On top of that we also offer an extended 2-year warranty on all components excluding wear and tear items such as bearings, brake pads, chains & cassettes etc. Our Warranty policy applies to the original owner and processed by our authorised retail partners. To see their warranty process check: www.nukeproof.com/warranty
- Where can I demo a Nukeproof bike?
- We run numerous demo's through the year at major events and with our dealer network. Check out www.nukeproof.com/demo for when we may be near you. If this is unavailable to you, you can always request a demo through your local authorised stockist.
- What size bike do I need?
- All our products come with a size guide. This is designed as an indication of the size that may suit you. If you are still unsure speak with one of our dealers who will be happy to help you pick the right size and model for you.
- How does you bike range work?
- Our range is named based on specification level. Not every Bike Frame will have each specification level, but in order of price they run: Sport - Race - Comp - Pro - Elite- Factory/ST (Reactor Only) - RS
Material: | Hydroformed 6061 Triple-Butted Aluminium |
---|---|
Fork Travel: | 150mm (RS 160mm) |
Axle to Crown: | 545mm (RS 555mm) |
Fork Offset: | 46mm |
Rear Travel: | 140mm |
Wheels Size: | 27.5" |
Max Tyre Size: | 2.6" |
Recommended Shock Sag (Measured seated): | 30% |
Shock Size: | 210x55mm |
Shock Hardware F: | 25x8mm |
Shock Hardware R: | 30x8mm |
Sizing: | S/M/L/XL |
Headtube: | 44-56mm Tapered Semi-Integrated |
Headset: | ZS44-28.6 - T2 / ZS56/40 - B8 |
Bearings Required: | 2x (6902 2RS), 4x (6800 2RS), 4x (6901 2RS) |
Seatpost: | 31.6mm (Internal Routing for Dropper Seatpost) |
Seat Clamp: | 34.9mm |
BB: | Threaded 73mm BSA |
Rear Hub: | Boost 148x12mm |
Rear Axle: | Sram Maxle Stealth M12x1.75 180mm (Thread Length 20mm) |
Chain Guide: | ISCG05 |
Brake Mount: | 180mm Direct Post |
Protection: | 3D Contoured Rubber Frame Protection for DT/SS/CS |
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