NUKE PROOFR EACTOR 290 CARBONST

£4,699.99 Exciting all-rounder with a penchant for descending

Nukeproof have taken their proven trail bike and pared it back to inject a little more efficiency but without losing its core handling characteristics.

The frame

To boost the bike’s sprightliness, Nukeproof haven’t just specced lighter parts, but have reduced rear wheel travel to 125mm (from 130mm on the standard Reactor), using a shorter-stroke shock. The ST is also designed for a 130mm rather than 150mm fork. While the other bikes here incorporate some form of frame flex into their suspension, the ST uses a conventional four-bar linkage with multiple bearings and pivots, including one on the chainstays.

Two ovalised chips sit at the top of the seatstays and attach to the swing-link that drives the shock. These can be flipped between ‘trail’ and ‘rail’ modes to adjust the geometry, changing the head and seat tube angles by 0.5 degrees and the BB drop by 6mm. In trail mode, our bike’s head angle was 66 degrees and the seat tube angle was a steep 76.2 degrees. The 460mm reach on the medium size offers a roomy, surefooted stance when out of the saddle, while the 440mm chainstays balance stability and agility nicely. At 330mm, the BB height is the closest to the ground of all the bikes on test, and nearer still in rail mode. Nukeproof only offer the Reactor ST with a carbon frame and in the build you see here.

The kit

Considering its kit, the Reactor’s price is really quite impressive. The 130mm-travel (the longest on test) Fox 34 Factory fork uses the brand’s highly-adjustable GRIP2 damper.

This works well with the DPS shock, which has a lever to toggle between open, medium and firm modes, plus a winged three-position dial so you can tune the feel of the open mode. The 12-speed Shimano XT drivetrain impresses, as always, with its precise shifting and reliability. Nukeproof have specced the two-piston XT brakes, rather than the four-pot version, but they still pack a punch – the 180mm rear rotor helps here. DT Swiss XR 1700 alloy wheels are wrapped in 2.3in Maxxis rubber.

The ride

The Nukeproof’s steep seat tube, decently long effective top tube (608mm, medium) and 50mm stem create a really comfy seated position, neither too stretched-out nor cramped. We were able to negotiate tricky uphill sections covered in stepped roots and slippery rocks without having to shift our weight around too dramatically in order

to maintain rear wheel traction or prevent the front wheel from lifting.

On smooth, long drags we did find ourselves reaching for the shock lever to firm up the supple back end and reduce pedal-induced bob. It’s by no means a bad climber but does lack the zip the other three bikes have in abundance. That’s partly down to its tackier, knobblier rubber (although the Spur does have a wide, grippy front tyre). At 13.65kg, the Reactor is packing around 2kg more weight than its competitors, too.

When aimed downhill, though, the ST’s trail bike genetics make it really come alive. Both tyres – a Minion DHF and Aggressor – offer decent traction through the turns, with prominent shoulder treads that dig into soft soil. The Aggressor clogs quite quickly in really gloopy mud, but it’s still the grippiest rear tyre here. Some of that downhill swagger also comes from the well-proportioned frame, with numbers that equate to stability and a BB height that lets you rail turns and elevates confidence over rough terrain.

Then there’s the suspension. The Fox 34 fork feels well-controlled and more than precise enough for this type of bike, while at the rear you’d be fooled into thinking there’s more than 125mm of travel at your disposal. This is both good and bad – it makes you want to ride the Reactor even harder, but then you soon start pushing it beyond its comfort zone. While the ST might not cover the ground quite as quickly as the best here, it’s still one hell of a bike.