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Coming in hot: The Nukeproof Reactor explodes onto the all-mountain scene

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The Reactor is Nukeproof’s first foray into the world of all-mountain bikes. Bearing absolutely no resemblance to the 1997 linkage suspension fork hardtail with which it shares its name, the Reactor fills the rather wide gap between the burly Mega enduro bike and the Scout hardtail. Available in both a 29″ version with 130mm rear wheel travel and a 27.5″ version with 140mm rear wheel travel, the Nukeproof Reactor is surely set to be an extremely popular bike when it hits the market today. This is a capable-looking bike and a lot will be expected from it following the success of the Mega. We rode the top-end build, the Nukeproof Reactor 275c RS, as part of our “Where to Ride Series” on the granite terrain of Scotland’s Aberdeenshire – click here for the first ride review, or watch the video below to see the Reactor in action at Pitfichie forest, home to the Scottish Enduro Series.

Nukeproof Reactor All-Mountain Bike

Nukeproof reactor 275c rs all mountain bike

The Reactor retains Nukeproof’s burly looking squared off top-tube tube profile, with some very sleek looking lines leading down the underside into the mount for the 210x55mm metric shock. The suspension platform is a swing-link driven 4 bar horst link layout said to give the rider a more progressive feel to the travel overall as compared to the Mega.

nukeproof reactor 275c rs review test

The frame is neat and tidy with an integrated seat tube gusset and the seat tube bend sits fairly close to the bottom bracket allowing plenty of room for a long travel dropper seat post. The top-tube mounted shock provides enough room in the front triangle for a 750ml water bottle, excellent news for those who can’t stand bladder hydration systems.

The Reactor’s geometry can be altered with the use of a flip-chip positioned where the seat stay meets the swing link

Now a common feature of many all-mountain and enduro bikes, the Nukeproof Reactor features a flip-chip at the seat stay-swing link interface allowing the rider to alter the geometry mid-ride. It is a simple job executed with the use of a hex key. Within about 2 minutes you can switch the Reactor from TRAIL mode, recommended for climbing and long pedally days in the saddle, to RAIL mode recommended for lift-assisted descend missions. In RAIL mode the bottom bracket height drops 6mm from an already-low 339 mm to 333 mm. It also slackens off the headtube angle half a degree to 65.5°.

nukeproof reactor 275c

Nukeproof Reactor Suspension Platform

Nukeproof say the suspension platform, serviced by a RockShox Deluxe Ultimate shock on the 275c RS build, has been designed to be less regressive than that of the Mega at the initial part of the stroke in order to provide more small bump sensitivity and more progressive support deep in the travel. Throughout the travel, the leverage curve shows 21.5% progression with an average leverage ratio of 2.4.

nukeproof reactor carbon

nukeproof reactor suspension kinematics

The anti-squat of the Nukeproof Reactor has been optimised to provide a solid pedalling platform in the small climbing gears, set to 92% in the Eagle drivetrain’s dinner plate ring (32/50). Nukeproof say the anti-rise characteristics of the suspension have been tailored to allow for some squat when breaking hard into a corner to allow for the maintenance of the rider’s position on the bike while pushing pressure into the ground for good traction under braking.

nukeproof reactor carbon mtb

This much tyre clearance on a medium 27.5″ with a 2.4″ WT Minion DHR II on a 28mm internal width Mavic Deemax rim

The wheelbase sits at a middle-ground value of 1185mm (medium) for a 140mm travel 27.5″ wheel MTB, with a chainstay length of 430mm allowing enough tyre clearance for up to 2.6″ wide tyres. The frame features a threaded bottom bracket, internal cable routing and has BOOST 148mm hub spacing.

Neither wheel has a quick release axle – 2 different sizes of hex key are required to remove the wheels

The 27.5″ and 29″ Nukeproof Reactor frames are two totally different frames that were designed and developed at the same time. The maneuverability of the 27.5″ really is second to none (first ride review here), especially on the lightweight top-end build 275c RS, but if you’ve the leg length to ride 29″ without the rear wheel getting in the way then Nukeproof recommend the 29″ for outright speed over the 27.5″. All 27.5″ models come with a 150mm travel fork, save for the 275c RS which is overforked with a 160mm travel Lyrik Ultimate RCT3 fork.

As is common for 29″ full suspension bikes, the rear wheel travel sits at 130mm, 10mm less than that of its 27.5″ counterpart. The fork travel also sits 10mm lower at 140mm on all builds except for the top end 290 RS which has a 150mm travel fork fitted.

46mm fork offset
The 27.5″ Reactor gets a 46mm offset 150/160mm fork
Geometry of Nukeproof Reactor 275 with 150mm travel fork
Geometry of Nukeproof Reactor 275 with 150mm travel fork
Geometry of Nukeproof Reactor 290 with 140mm travel fork
Geometry of Nukeproof Reactor 290 with 140mm travel fork

Geometry wise, the Nukeproof Reactor 290 frame shares the same 65.5° headtube angle and 75° effective seat tube angle (RAIL mode) as the 275 but gets an extra 10mm in the chainstay, bringing it to 440mm, an extra 20mm in the wheelbase bring it to 1205mm (medium) and a slightly shorter reach of 451mm. The 290 also gets a 51mm offset fork as compared to the 46mm offset fork of the 275, working to reduce the additional trail that comes with the bigger wheel.

caarbon mtb frame protection nukeproof

We really like the frame protection the Reactor is fitted with – the underside of the downtube gets a not insignificant 3D contoured rubber panel to protect from rock strikes, and the drive side chainstay gets a robust looking chain slap protector, as does the inside of the drive side seat stay.

nukeproof frame details

nukeproof reactorAside from the giant “NUKEPROOF” spread across the downtube, the rest of the frame detailing is kept to a minimum with the name “REACTOR” almost hidden out of sight on the inside of the non-drive side chainstay. Covert.

We rode the Nukeproof Reactor 275c RS on our Aberdeenshire enduro trip- full the first ride review click here

Sizing, Pricing & Availability

The Nukeproof Reactor 275 will be available sizes S, M, L and XL while the 290 will be available in M, L and XL. For the first time, Nukeproof are offering riders a full UD woven carbon frame in both wheel size options. There are also aluminium frame options which feature carbon seat stays to help reduce the unsprung weight.

Nukeproof Reactor 290 Factory in Bottle Blue

The Reactor will be available at no fewer than 6 price points per wheel size, including a top-end Fox Factory build at £4899.99 (~$6040), and the top-end RockShox build at £5399.99 (~$6650).

nukeproof reactor 29er
Nukeproof Reactor 290 Pro featuring a RS Pike fork will set you back £4399.99

If you can’t remortgage your house to fork out for these high-end builds, Nukeproof offer an entry level Comp version of both the 275 and 290 priced at £2749.99 (~$3390), which will get you a RS Revelation RC Fork, the RS Super Deluxe Select Shock with custom ML tune, a SRAM SX Eagle Drivetrain, Sun Ringle Duroc Wheelset and SRAM Guide T brakes. All models come with tacky Sam Hill signature grips and the new Maxxis Assegai tyre up front. You can also pick up just the frame and shock (Super Deluxe Ultimate) at £1899.99 for the alloy, and £2499.99 for the carbon.

Nukeproof Reactor 275 Elite model comes in at £3799.99

Stock doesn’t land until mid October so you’ve a wee while to wait before you can get your hands on one. To see the Nukeproof Reactor 275c RS in action on the granite rock enduro trails of Aberdeenshire, Scotland, click here.


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Matus Kuchyna
Matus Kuchyna
4 years ago

Scott Spark 2015

4 years ago

“There are also aluminum (sp) frame options which feature carbon seat stays to help reduce the unsprung weight……”

Odd choice of marketing speak by Nukeproof. Weight difference would seem very minimal at best, and for durability’s sake, I think the buying public would like the materials reversed given the choice.

All said, bummer they don’t offer full alloy model given they are a in-house mail order brand and their ceiling (IMO) is $3.5k and under on a complete….Given the (lack) level of customer service that Chain Reaction provides, no way am I plunking down anything over that for a bike through them. I tried, never again, but YMMV.

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