2021 Nukeproof Mega 275 Factory – First Ride Review

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The Nukeproof Mega has been the brand’s top flight, big hitting enduro bike since 2011. The original prototype was raced to 3rd place in Masters at the 2009 Megavalanche (the race it was named after) by Michael Cowan, with the first production bike being launched to the public two years later in 2011.

Since that original prototype, the Nukeproof Mega has been in a state of constant evolution from V1 up to V3.B, with new updated frames launching every couple of years. As wheel sizes have come and gone so have the options with the Mega, with both 27.5in and 29”in wheeled options being made available.

2021 Nukeproof Mega 275 Factory
The brand new 2021 Nukeproof Mega Factory 275

Today sees the next step in that evolution with the launch of the brand new Nukeproof Mega V4, and we’ve been lucky enough to get our hands on one for the past week and put it through its paces. 

Nukeproof Mega 2021 – What’s Changed?

Designed with input from 3 x Enduro World Series champion Sam Hill, the new Mega has been designed from the ground up to be the ultimate enduro race bike. Capable of taking on the world’s longest and roughest race tracks, yet still efficient and comfortable enough to pedal all day on long transitions.

At the heart of the new Mega is a brand new frame that delivers 165mm or 160mm (depending on wheel size) of rear wheel travel. While the frame is all new, the designers at Nukeproof were keen to ensure that it still looked like a Mega and key design points, such as the parallel top tube and chainstays, were to carry over from previous generations.

2021 Nukeproof Mega 275 Factory

Available in both full carbon and aluminium framed models, along with 27.5in and 29in wheeled variants, the new Mega has been given a good dose of the long, low, slack treatment. But rather than just slackening out the head angles and focusing on descending, Nukeproof has also put a focus on the seated position of the bikes, paying particular attention to a measurement they have coined ‘saddle offset’. 

This is essentially the position of the saddle behind the bottom bracket, at any given height. By working out what they determine to be the optimum offset (which changes per size) for seated weight distribution, this has led Nukeproof to steepen seat angles across all sizes, but especially on the larger sizes to cater for taller riders, while also increasing the reach numbers to give longer ETT. To further increase bike fit, the new Mega is now available in five sizes, from S – XXL, and Nukeproof has evened out the jumps between sizes, while also keeping the seat tubes as low as possible for maximum seat post insertion and standover.

Our size large test bike, rolling on 27.5in wheels, has been designed around a saddle offset of 178.28mm at a saddle height of 750mm. The seat tube angle is a nice steep 78 degrees (effective – actual is 71), with a reach of 480mm. This steep seat tube means the ETT is a relatively modest (for the size) 611.45mm. The head angle on both the 27.5in and 29in version of the bike sits at 64 degrees and all sizes share the same chainstay length, which varies 5mm between 27.5in and 29in – from 435mm to 440mm.

While the new Mega still uses a swing link driven four bar Horst Link suspension design, the kinematics have been tweaked to be really supple in the initial part of the stroke, whilst then being progressive enough to offer plenty of support deeper into the stroke. The new V4 Mega has reduced overall progression from sag (17% compared to 22%) to increase tunability but a high average ratio (2.6 compared to 2.5) for increased sensitivity. Compared to the previous model, the suspension forces are also lower pre-sag and higher post sag to again increase sensitivity at the start of the stroke, yet provide more mid stroke support.

To tie in with the focus on steepened seat tube angles and saddle offset for better seated positions, Nukeproof has also also increased the anti squat value at sag over previous iterations of the bike for increased pedalling characteristics. The new V4 has an anti squat value of 102% where the V3 was 96%. This value then drops off through the stroke allowing the suspension to work, and offering great small bump compliance while helping to eliminate trail chatter.

The V4 has also been given a lower anti-rise value than its predecessor to make it more active under braking. The new kinematics allow some squat under hard braking, maintaining the rider position yet still offering a good amount of pressure through the tyres for traction. 

Nukeproof Mega V4: The Build

The Mega V4 is available in three carbon framed and two alloy framed models, with prices ranging from £2,699 to £5,499, along with a frame-only option including a Fox X2 Factory for £2,499 and £1,799 for carbon and alloy respectively. The bike we’ve had on test is a size large, Mega Factory Carbon 275, which retails for £4,999 and comes dripping in top end kit. Where previously the carbon bike had featured alloy seat stays, the new V4 is a full UD T700/800 carbon frame. The main pivot uses a collet for added increased stiffness and all bearings are Enduro Max for additional durability.

One big change from previous versions that will please a lot of people is the provision of bottle mounts. The frame will take a 750mm bottle across all sizes, and if you look under the top tube you’ll also find an additional set of mounting points for accessories.

The bike features full internal cable routing, with hoses entering the headtube before exiting the bottom of the seat tube, then into the seatstays. The carbon frame also features internal guides for ease of use and maintenance

Under the downtube / BB area you’ll find a custom moulded frame protector to ward off rock strikes. Along the drive side chainstay is a moulded, castellated, protector to protect from chain slap and keep things nice and quiet.

As you’d expect from a Factory model, the Mega Factory features top end suspension. Up front is a stout stanchioned Fox 38 Factory Float Factory Series with the amazing Grip 2 damper, delivering 170mm of super composed travel, while out back is a Fox Float X2 Factory Series Evol that takes care of the 165mm of trail-taming bounce.

Stop and go on the Factory are both taken care of by Shimano with a full XT 12 speed drivetrain offering plenty of range for grinding up long fireroad transitions, and sprinting into stages. Matching the drivetrain is a pair of powerful Shimano XT 4 piston brakes clamping onto IceTech rotors with a 203mm up front and a 180mm out back. 

The Factory model rolls on a set of burly aluminium DT Swiss EX1700 enduro wheels that use the company’s reliable 350 Ratchet hubs. Wrapping those rims are a set of aggressive Michelin Wild Enduro tyres in sticky Gum X compound.

Given the popularity and quality of Nukeproof’s accessory range, it’s no surprise to see a load of own brand finishing kit on the Factory. Bars and stem are both Horizon with a 25mm rise bar held in place with a 50mm stem. Grips are a set of Sam Hill signature and rounding out the contact points is a Nukeproof Horizon Enduro saddle, attached to a Bike Yoke 150mm dropper with Shimano lever.

Nukeproof Mega V4 Set Up

With the Mega Factory running Fox suspension front and rear, initial set up was nice and easy using the online Fox guides. Using the suggested settings I started with the fork at 97psi to give 34mm sag (around 20%) and the low speed and high speed compression at 4 and 5 from fully closed respectively, High speed rebound and low speed rebound were initially set at 5 and 10 out. 

2021 Nukeproof Mega 275 Factory
The X2 Factory offers masses of adjustment

The shock was similarly easy to set up using the guides and I started with around 230psi to give me 19mm (30%) sag and and the low speed and high speed rebound being set at 7 and 3 out, while the LSC and HSC were set at 8 and 5 out.

The Ride – Climbing

Swinging a leg over the Nukeproof Mega for the first time it immediately felt familiar with the geometry as you’d expect from a bike with enduro intentions. The steep seat angle and longish front end put you in a comfortable position for sitting and spinning along, and flat pedals are dispatched with ease.

2021 Nukeproof Mega 275 Factory

Once the gradient increases the Mega does a good job of getting you to the top with minimal fuss. The anti squat and supportive rear end do a good job of transferring power to the back wheel, and into forward motion, with no noticeable pedal bob. The balanced front and rear ends put you in a centred position on the bike adding grip on steep inclines, with just a shift in body weight needed to get up and over techy trail obstacles.

One issue I have had though is heel rub on the drivesde seatstay. Admittedly my right foot does sit at a slight angle, but the seat stay is quite bit wider than the chainstay and I found myself clipping it quite a bit.

The Ride – Descending

Once things start pointing down the geometry of the Mega V4 feels great. The 480mm reach, coupled with the 440mm chainstays put you in the centre of the bike and give a good balanced feel when speeds increase or you’re pushing hard into turns. 

After an initial ride though, I wasn’t too happy with how the bike felt and felt I could get more from it. I reduced the air pressure in the fork a couple of psi while also backing off the HSC and LSC a couple of clicks, and speeded up both rebounds a click. I then backed off the HSC and LSC on the shock a couple of clicks.

2021 Nukeproof Mega 275 Factory

From that point the Mega has felt good – really good, removing trail chatter and staying really supple, while also offering plenty of support and grip. The rear end does an amazing job of soaking up smaller rocks and roots, while staying supportive enough to load up and pop over trail obstacles, and boost off lips. The bike is nimble and confident in the air, letting you look for bonus lips and sends, and soaks up shady landings letting you get away with more than you should.

On fast and rough tracks, the slack front end and chunky, well damped fork let you pick a line, get off the brakes and charge on, knowing that it’ll stick. And the rear doesn’t doesn’t disappoint either taking big, and square edge hits in its stride, and the more you push it the better it feels. Likewise, pushing into fast turns, the rear end feels great. The mid stroke support adds loads of grip, letting you really push the back end into the turn.

2021 Nukeproof Mega 275 Factory

The slack head angle and good length front end add plenty of confidence on steep tracks, allowing you to stay centred on the bike, weighting the front end, and pushing the chunky aggro tyre into the dirt for grip, then snapping the back end round.


It’s been a while since I spent any proper time on a 27.5 bike, and I’ve got to admit I was a bit dubious, but the Mega 275 has really impressed me. It’s fast, fun, likes to jump and is good in the turns. The rear end offers plenty of support, yet remains supple and does a great job of tuning out smaller hits, letting you concentrate on going fast. 

2021 Nukeproof Mega 275 Factory

While it’s no doubt an ‘enduro’ bike, it’s also fun and nimble, and is just as happy playing in the woods as going flat out in steep and rough terrain. Get it up to speed and it’s composed and confident, with suspension that lets you charge into the roughest of tracks, while feeling easy to move around in tight terrain. While a lot of brands are moving solely to 29in wheels for their longer travel bikes, the Mega 275 Factory shows that smaller wheels can still have a place for those looking for something that is as fun as it is fast.

Review Info

Brand: Nukeproof
Product: Mega 275 Factory
From: Nukeproof
Price: £4,999
Tested: by Ross for 1 week
Author Profile Picture
Ross Demain

Ad Sales Manager

Ross pairs his childlike excitement for bikes with a complete disregard for the wellbeing of his ribs, or his rims. Best known for riding cheeky trails, his time is also spent trail building in his local woods, drinking beer, eating pies and entertaining his two children.

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Comments (3)

    I don’t know why you’re surprised it was good just because it wasn’t a 29er. If anything the smaller wheeled bikes do tend to be more nimble (subject to similar travel and geometry) and playful – but admittedly not as fast. I’m not a racer (nor will I ever be) – so mtb is all about just having fun whatever I’m riding on 2 wheels. If it’s a 29er or 650b that gives me the most fun I’ll go with that.

    Everything is great on that bike apart from the colour. Yuk. Why couldnt Nukeproof have had a full build with that bright yellow?

    @joebristol Hi Joe, I wasn’t surprised it was good, I was surprised how good it felt. I’ve spent a lit of time this year on longer travel 29ers and definitely see the benefits for going fast and carrying speed. This bike has been designed as an enduro race bike, which means speed, and as you point put 27.5 isn’t always as fast.

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