Nukeproof bikes have long been a favourite with privateer enduro racers. But the decision about which bike to race got a lot harder in 2021. Because, not only did Nukeproof launch the new V4 Mega, it also released the brand new 170mm travel Giga.

Read more: Buyer’s guide to the best enduro mountain bikes

But which one is better? It’s a question that any serious enduro racer should be asking. And in an attempt to answer that question, we’ve been testing the Giga 290 Carbon Factory and the Mega 290 Carbon Factory side by side.

Frame sizes

Both bikes are available in five frame sizes, and both come with the option of 29in or 27.5in wheels. The ranges run from RS to Comp, with the Factory level Mega build featured here taking up the middle ground and the Factory Giga sitting at the top of the pile. Not that anyone thinks that Fox Factory 38 forks and X2 shocks can be considered middle of the road.

Pricing

The bikes are competitively priced too, the Giga 290 Carbon Factory costing £5,499.99 and the Mega 290 Carbon Factory sneaking in at £100 less. And both have almost identical specifications. We say almost because the XT rear brake on the Giga has a 203mm rotor, while the Mega comes with a 180mm rotor as standard. Other than that, everything else is the same including the 170mm Bike Yoke droppers, DT Swiss EX1700 wheels, Shimano XT drivetrains and Nukeproof 31.8mm bars and stems. All great kit then.

Weight

Weight-wise, there’s not much separating the bikes here either. Frame weights without the shock are 2.8kg for the carbon Mega and 2.9kg for the carbon Giga. So the Mega frame is only 100g lighter than the Giga. That’s not the whole story however, as the single pivot swingarm on the Giga is actually 100g lighter than the four-bar design on the Mega. However, the front end and linkage on the Giga is 200g heavier which results in the 100g overall increase in weight. And while you could argue that this gives the Giga a more favourable sprung to unsprung mass ratio; have you ever noticed your suspension change when you add a water bottle? No, nor have we, and a full bottle weighs approximately 675g. So let’s park that for now.

The complete weight for each bike with Maxxis EXO+ casing tyres is 15.58kg for the Mega and 15.51kg for the Giga. But how can it be that the Giga is 70 grams lighter than the Mega when the Giga frame is 100g heavier? Well, when we just measured the chassis without the wheels the Mega is in fact lighter as per the frame weight, but when we measured the wheels it’s clear the tyres on the Giga were lighter but still within the expected variation. The key takeaway then is that at approximately 15.5kg both bikes are competitively light.

Enduro race bikes need to be fast, and the new Mega keep it’s eye on the prize.

Geometry

In terms of geometry the most pronounced difference between the bikes is that the head angle on the Giga is almost 1º slacker than the Mega, which gives it a slightly longer front center even though both size L bikes have similar reach measurements; 470mm on the Giga Vs 468mm on the Mega. The Mega does have a 10mm taller head tube though, so if we equate for stack height, the Mega has a slightly longer reach. As you can see, we’re splitting hairs, and it’s the same elsewhere with the geometry. The Giga has a 3mm longer chainstay length – 445mm Vs 442mm – and the BB height is 2mm taller on the Giga, but it also has more travel – 170mm Vs 162mm – so the dynamic BB heights will be very close. And it’s worth noting that these are our measured numbers, not Nukeproof’s claimed geometry.

Measured geometry (size L Giga and Mega side by side)

Suspension

It’s only when you dig into the rear suspension layouts that you start to see the variation between both designs. On the surface, the most obvious difference is that the Mega uses a classic four-bar linkage suspension design with counter rotating links. Nukeproof’s listed travel is 160mm, but we measured it at 162mm, so it over-delivers on that front. The Fox Float X2 shock on the Mega has a 230mm eye-to-eye length with a 62.5mm stroke, where the leverage rate is initially digressive but rapidly switches to a progressive rate. On the leverage rate graph you can see that it even runs parallel to the curve of the Giga in the last 50 per cent of the travel. In fact, the V4 Mega has a very similar suspension layout to Nukeproof’s acclaimed trail bike, the Reactor.

Leverage curves for the Giga (left) and Mega (right)

Now contrast that with the Giga, which takes its design cues from Nukeproof’s Dissent downhill bike. As such, it is a single pivot design with a linkage actuated shock. It’s running a 205x60mm Fox Float X2 shock and delivering 170mm of travel, so the overall leverage ratio is higher than on the Mega. Take a closer look at the leverage rate curves and it’s clear that the Giga is progressive from the off. In fact, the progression rate on the Giga is adjustable thanks to the asymmetric main pivot assembly that offers two settings. In the low pivot position overall progressivity is 25.5 per cent increasing to 29 per cent in the high pivot setting, which should make running a coil sprung shock super easy.

And while both bikes have four-way adjustable Fox Float X2 shocks, the stock tunes are different. The X2 on the Mega has an L1 compression tune which is slightly lighter than the Giga’s L compression tune. Which makes sense as the Giga has a higher overall leverage ratio, as it has more travel from a shorter stroke shock, and as such needs a slightly firmer shock tune. For reference, here are the suspension settings we ran on both bikes for an 80kg rider, and all taken from a fully closed position:

• 180psi
• LSR 13
• HSR 4
• LSC 13
• HSC 8

• 190psi
• LSR 11
• HSR 5
• LSC 11
• HSC 8

How do they ride?

So we have two big hitting enduro bikes with similar geometry, sizing, specification and weight, but they also have unique ride qualities due to the differences in their suspension outlined above. The Mega has a more pitter-patter response to the rear that’s great at ironing out small high frequency hits. Not only does this allow you to carry speed incredibly well on choppy terrain, it also reduces rider fatigue, which is critical on longer enduro stages where fatigue management is every bit as important as rider skill and fitness. Riding the same trails back-to-back, the Mega’s ability to glide over the rough stuff made it feel as if the rear tyre was a couple of psi lower than on the Giga, when we were in fact running identical tyres and tyre pressures on both bikes.

Stiff and direct, the full carbon frame is great for slamming turns.

And while the Giga couldn’t quite match the magic carpet ride offered by the Mega, it more than made up for it with increased stability. On the Giga you ride very centered on the bike, much in the same way you would on a well balanced downhill rig. So while the high frequency vibrations are more noticeable on the Giga, its inherent stability gives you the confidence to push harder and ride less conservatively. In fact, confidence on the Giga is simply off the charts. This was most apparent on the jump lines at BikePark Wales, where the stiffer suspension, and probably the stiffer frame, made it super easy to maintain speed through big sweeping berms and while getting airborne on jumps. The Giga is not so stiff that it can’t be rallied down through wet slippery roots though; the 31.8mm diameter alloy bar and alloy DT Swiss EX1700 wheels see to that. Yes, the Giga is a little more poppy and playful than the Mega, but it doesn’t have the same ability to plow straight through the roughest terrain and you have to work harder to stay centered on the Mega.

How both bikes respond to pedalling efforts is slightly different too. The Mega feels a hair faster out of the blocks, the Giga slightly slower to wind up. We weren’t aware of the anti-squat number before coming to that conclusion, so we were pleased that our seat-of-the-pants feel tallied up with Nukeproof’s data.

The Mega has 76.4 per cent anti-squat in the 32/16t gear at sag, which is almost 10 per cent more than the Giga. Shift up to the 50t cog and both bikes have around 100 per cent anti-squat. This, combined with the relatively steep effective seat tube angles, means that both bikes climb efficiently enough to comfortably get you to the top of even the steepest descents.

The new Mega feels great in the air, but how does it handle the rough stuff?

Which one should I choose?

So which bike is best? Well, that really depends on what you’re after and what your needs are. If you’re racing enduro at the highest level we think the Mega takes the lead as it better isolates you from the onslaught of repeated hits. So in theory you should be able to stay fresher for longer and ultimately ride faster with fewer mistakes. And that’s not only important on the timed stages, but all of the practice sessions and cumulative fatigue that builds up over a race season too.

If, however, it’s thrill seeking rather than clock-watching that’s your number one priority, and you’re likely to spend just as much time doing hot laps in the bike park as travelling to races, the Giga would be our first choice. Either way, Nukepoof has you covered as the Giga and Mega are both great bikes, and even though they seem really close on paper, ride them back-to-back and it’s instantly apparent that they have unique strengths and very few weaknesses.