After the disappearance of the Mega TR in 2016, Nukeproof were left without a dedicated short-travel trail bike in their range. However, that gap has now been filled! The new Nukeproof Reactor 275 has 150/140 mm travel 27.5” wheels and a fun-loving attitude. Read our first impressions here!
Do you prefer to race or play? Does speed take priority over fun? And do you prefer to chase Strava segments or session loamy corners? These are the questions you will have to ask yourself when deciding between a Reactor 290 and a Reactor 275, as Nukeproof are offering their new trail bike in both 29” and 27.5” options. The 275 model we tested is supposedly all about having fun. Its smaller wheels should boost maneuverability and really encourage you to play with the trail ahead. We took one for some laps of our local riding spot in Scotland to see how it performs.
The new Reactor 275 RS in detail
The Reactor takes its name from Nukeproof’s original trail hardtail from the ‘90s, however, it does not have much in common with its namesake. Starting fresh allowed Nukeproof to design the new Reactor from the ground up. They claim this has allowed them to create the ultimate trail bike for taking on demanding terrain.
The Reactor shares Nukeproof’s swing-link driven 4-bar Horst layout with their Dissent DH bike and the latest Mega enduro bikes. The Reactor’s suspension system features 21.5% progression and, according to Nukeproof, has better sensitivity at the start of its travel as well as increased mid and end-stroke support when compared to the Mega. Anti-squat is around 92% at sag (in a 32-50t gear ratio).
The frame features a flip-chip as well as a number of details that give it a quality feel. The flip-chip lets you adjust the Reactor’s head angle and bottom bracket height by choosing between a “Trail” and “Rail” setting. In the lower “Rail” setting, the head angle is slackened by 0.5° and the bottom bracket height is lowered by 6 mm, taking the bottom bracket drop to -24 mm.
The spec of the Nukeproof Reactor 275 RS
The 275 RS is the flagship model in Nukeproof’s 27.5” Reactor lineup, so it is no surprise to see it decked out with some seriously nice components. It is easy to see that Nukeproof have specced their top model primarily for descending performance – this bike has a burly build! The suspension of the RS model is taken care of by top of the range RockShox products. Upfront, a RockShox Lyrik Ultimate delivers 160 mm travel and is matched with a RockShox Super Deluxe Ultimate rear shock. A SRAM X01 Eagle drivetrain delivers crisp shifting performance and the powerful SRAM Code RSC brakes are a great choice in our opinion, as they deliver very usable power and are easy to modulate. Providing grip are two of our favourite MAXXIS tires (the Assegai 2.5 WT and Minion DHRII 2.4 WT) which are mounted to a Mavic Deemax DH wheelset. A RockShox Reverb Stealth dropper and Nukeproof finishing kit complete a very solid build.
Fork RockShox Lyrik Ultimate Charger 2 RTC3 160 mm
Rear shock RockShox Super Deluxe Ultimate RTC 140 mm
Brakes SRAM Code RSC 200/180 mm rotors (f/r)
Drivetrain SRAM X01 Eagle
Seatpost RockShox Reverb Stealth 125/150/170/200 mm
Stem Nukeproof Horizon 50 mm
Bars Nukeproof Horizon Carbon 780 mm
Wheels Mavic Deemax DH 27.5″
Tires MAXXIS Assegai 2.5 WT EXO+, Minion DHR II 2.4 WT EXO+
Weight 14.1 kg (Medium)
Price € 5,399.99
The geometry of the Nukeproof Reactor 275 RS
The geometry of the Reactor 275 stays the same between the carbon and alloy models. However, the RS model we tested comes with a 160 mm fork (instead of 150 mm) which slackens the head and seat angles slightly and raises the front of the bike a little as well as shortening the reach by a couple of millimeters. The 65° head angle and oversized fork give the Reactor 275 RS a very confident front end. It loves chopping through rough trails and stays unfazed on the steeps. The seat angle could be a tad steeper (74.6° in low setting), however, the pedaling position still feels comfortable enough for steep ascents and long days in the saddle. Overall, the geometry and handling are more on the playful side, but that doesn’t mean that the Reactor 275 can’t hold its own in the rough.
| Size (Low) | S | M | L | XL |
|---|---|---|---|---|
| Seat tube | 381 mm | 420 mm | 458 mm | 508 mm |
| Top tube | 581 mm | 611 mm | 641 mm | 676 mm |
| Head tube | 110 mm | 115 mm | 120 mm | 125 mm |
| Head angle | 65° | 65° | 65° | 65° |
| Seat angle | 74.6° | 74.6° | 74.6° | 74.6° |
| Chainstay | 430 mm | 430 mm | 430 mm | 430 mm |
| BB Height | 333 mm | 333 mm | 333 mm | 333 mm |
| Wheelbase | 1154 mm | 1185 mm | 1216 mm | 1251 mm |
| Reach | 420 mm | 450 mm | 478 mm | 512 mm |
| Stack | 603 mm | 609 mm | 613 mm | 617 mm |
How does it ride? The Reactor 275 RS on the trail
We tested the Nukeproof Reactor 275 RS on our home trails and ran it in the lower “Rail” setting. Climbing with the Reactor 275 RS is a comfortable affair. The bike climbs well and feels more than suited for long days in the saddle. It’s not as fast as an XC-racer but eels more eager up the climbs than an enduro sled. There is some pedal-bob when spinning at a high cadence on flatter sections of trail due to the lower anti-squat, however, this can be eradicated by using the adjustable damping switch on the shock. The seat angle on the RS build is not the steepest at 74.6° (in the “Rail” position), so if you regularly encounter long, steep climbs we would recommend sliding the saddle forward on its rails to keep your weight nice and central.
Descending on the Reactor 275 RS is all about one thing – having maximum fun. The bike is incredibly easy to flick around and loves to pop off roots, rocks and jumps. The suspension is not the most supple, instead, it has loads of mid and end stroke support. This means that the bike maintains its geometry when cornering hard or landing deep off a jump or drop. It also gives the Reactor a bottomless feel and means the bike has enough reserves for flowy bike-park trails and steeper enduro tracks.
Descending on the Reactor 275 RS is all about one thing – having maximum fun and playing with the trail
Aside from its playfulness, we also noticed how quiet the Nukeproof Reactor 275 is on the trail. There is no chain slap or rattling to be heard. The only sounds we observed whilst riding the bike was the noise of the MAXXIS tires hooking up with the dirt and the suspension swallowing up hits. Speaking of the suspension, Nukeproof’s new 4-bar Horst layout provides bucket-loads of support and traction. The Reactor feels balanced in the corners and allows you to efficiently generate speed when pumping through berms and rollers. Whilst riding the bike it is clear to see why Nukeproof chose to go with a no-nonsense, heavy-duty spec. The bike feels tough, confident and begs for flat landings and squared-off corners. So, how do you choose between the Nukeproof Reactor and the Nukeproof Mega, its longer travel stablemate? We can safely say that unless you only want to ride the gnarliest terrain around, you will have more fun on the shorter travel Reactor. It won’t hold you back!
Conclusion
The Nukeproof Reactor 275 RS is awesome fun to ride. In its 27.5” guise, the Reactor is best suited for a rider looking for a do-it-all trail bike who prioritises fun over flat-out charging. If you want a more planted bike with greater ability to carry speed, the 29” models are probably better suited for your needs. Overall, the Nukeproof Reactor 275 RS impressed us with its playful nature, bombproof spec and fair price. We look forward to comparing it against its toughest competition soon.
For more info head to: nukeproof.com
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