The NOX HeLIUM 5.9 ALL-MOUNTAIN is no ordinary eMTB. The small battery, compact FAZUA motor and modern geometry all look promising. Can the HeLIUM deliver on the trail?

NOX HeLIUM 5.9 ALL-MOUNTAIN Pro | FAZUA Evation/252 Wh | 160/150 mm (f/r) | 19.18 kg in size L | € 7,999 | Manufacturer’s Site

NOX is one of the few brands to rely on the FAZUA Evation system in a full-suspension eMTB. Together with the Lapierre eZesty, the HeLIUM is part of a new category of lightweight eMTBs with minimal support. The idea behind it is that with less power, the battery doesn’t have to be that big, significantly improving the handling thanks to the lower weight and more compact dimensions of the system. On top of that, the FAZUA battery and motor are easy to remove, allowing you to ride the HeLIUM like a non-motorised bike. The NOX HeLIUM is available in an enduro version with a full 180 mm travel and in the all-mountain configuration with 160/150 mm travel. Both versions are available with either 27.5” or 29” wheels. Our € 7,999 NOX HeLIUM 5.9 ALL-MOUNTAIN test bike came with 29” wheels and weighs in at 19.18 kg.

The NOX HeLIUM 5.0 ALL-MOUNTAIN Pro in detail

Looking at the NOX HeLIUM 5.0 ALL-MOUNTAIN Pro, it’s obvious that this is the flagship model. The decals and hardware on the black carbon frame pick up on the gold stanchions of the FOX Factory suspension and the SRAM XX1 drivetrain. The FOX Transfer dropper post also features that gold tone of the Kashima coating and, more importantly, offers a full 175 mm travel. The rest of the componentry is of equal quality and, for the most part, very sensibly chosen. Continental’s Der Baron tires are mounted on Stan’s NoTubes Arch CB7 wheels. We would have preferred a 200 mm rotor on the rear wheel to go with the MAGURA MT7 brakes, but you can order the bike with 200 mm rotors front and rear at no additional cost – so keep that in mind when you’re placing your order.

The grips, brakes and drivetrain perform without fault. However, MAGURA’s Shiftmix clamps position the shifter quite far away, making it difficult to reach. Our tip: swap the left and right clamps with each other.
On request, the HeLIUM can also be supplied with a 200 mm rear brake rotor at no extra charge. We strongly recommend it.
Gold as far as the eye can see. Shifting is taken care of by SRAM’s XX1 Eagle …
… and the gold Kashima coating of the FOX Factory suspension also picks up on the details of the frame
Incidentally, the decals are deliberately offset – love it or hate it

The FAZUA Evation motor is integrated into the slender down tube. The relatively small 250 Wh battery also helps keep everything a lot more compact compared to a conventional eMTB. Constructed as a single unit and weighing 3.3 kg, the 60 Nm motor and battery can easily be removed from the down tube. Only the gearbox around the bottom bracket remains in the frame. This allows you to ride the NOX HeLIUM un-motorised and with minimal added weight. The best part is the cover that NOX have included, which allows you to transform the down tube into a huge trunk. However, we only recommend stowing soft objects in here because things like your multitool will make a racket when you ride.

Almost the entire FAZUA system including the battery and motor can be removed from the bike in no time at all
Only the gearbox around the bottom bracket remains in the frame, allowing you to ride the NOX HeLIUM like an unmotorised bike …
… with the added bonus of huge storage compartment in the down tube. You get two bikes in one.
There’s a built-in lock as a deterrent against theft
If left unlocked, the system can be removed on the trail without the use of a key, which is very practical
The FAZUA battery enters a deep sleep mode after eight hours of standby. Once it does, you have to use the on-switch on the battery itself to power the system up since it won’t work from the remote.
The speed sensor is very exposed on the chainstay. The spoke magnet can easily twist or fall off. We’ve come to expect better integration.
From a distance, the cockpit looks neat and tidy …
… but the bulky remote on the HeLIUM offers room for improvement

NOX HeLIUM 5.9 ALL-MOUNTAIN Pro

€ 7,999

Specifications

Motor FAZUA Evation 60 Nm
Battery Evation Battery 250 Wh
Display FAZUA Remote b
Fork FOX 36 Factory Grip 2 160 mm
Rear Shock FOX Float X2 Factory 150 mm
Seatpost FOX Transfer Factory 175 mm
Brakes MAGURA MT7 200/180 mm
Drivetrain SRAM XX1 Eagle 1x12
Stem Renthal Apex 35 40 mm
Handlebar Renthal Fatbar Lite Carbon 780 mm
Wheelset Stan’s NoTubes Arch CB7 29"

Technical Data

Size M L
Weight 19.12 kg
Perm. total weight 130 kg
Max. payload (rider/equipment) 110 kg
Trailer approval n/a
Kickstand mount yes

Specific Features

modular FAZUA-motorsystem

Geometry and sizing of the NOX HeLIUM

Regarding geometry, the NOX HeLIUM ALL-MOUNTAIN is bang up to date. With 470 mm reach (size L) and a head angle of 65°, it makes no secret of its hankering for speed. At 74.5°, the seat tube angle seems somewhat slack at first. However, there is no bend in the seat tube so the angle doesn’t slacken out as you extend the dropper. How that translates on the climbs, we’ll get to later. For a 29” eMTB, the 453 mm chainstays are neither short nor long. Though, compared to the non-motorised trail bikes that the HeLIUM has to compete with, they’re very long. Unfortunately, NOX are currently only offering the HeLIUM in sizes M and L. Smaller riders who prefer riding a longer bike by sizing up will have to pay attention to the length of the seat tube. At 478 mm, it limits the choice between sizes. Particularly short and tall riders will have to look elsewhere.

Size M L
Seat tube 433 mm 478 mm
Top tube 610 mm 635 mm
Head tube 135 mm 135 mm
Head angle 65° 65°
Seat angle 74.5° 74.5°
Chainstay 453 mm 453 mm
BB Height n/a n/a
Wheelbase 1249 mm 1259 mm
Reach 446 mm 470 mm
Stack 613 mm 617 mm

NOX HeLIUM 5.9 ALL-MOUNTAIN Pro on test

Despite its long geometry, the riding position on the HeLIUM is sufficiently comfortable for long transfers and all-day rides. As soon as things start going uphill, the HeLIUM reveals the benefits of its straight seat tube even more clearly, feeling significantly steeper than the specified 74.5°. Even tall riders who have a lot of seat post sticking out remain centrally on the bike. Together with the long chainstays, the front wheel stays firmly planted no matter how steep the incline.

The pedalling position on the NOX HeLIUM is spot on

The assistance of the FAZUA Evation motor is clearly noticeable in the highest of its three support modes (Rocket mode) with a maximum torque output of 60 Nm. However, if you’re expecting the same power as from a Bosch or Shimano motor, you’re bound to be disappointed in the FAZUA. Rocket mode is roughly comparable to Bosch’s Tour mode, which is just above Eco. The motor in the HeLIUM is very easy to modulate, making the bike easy to control on technical climbs. Combined with the active suspension and sufficiently grippy tires, the wheels don’t spin even when you’re riding over wet roots, slippery rocks or patches of snow. The only time we ever used the two lower support modes was when riding in a group with non-motorised mountain bikers. These two modes are neither particularly powerful nor noticeable, in which case you have to contend with pedal bob. You can calm the rear end down either by activating the climb switch or putting the motor back into Rocket mode to keep the chain tensioned.

If you want to keep up with conventional eMTBs, you’ll have to put down the power on the NOX HeLIUM with its FAZUA motor.

Obviously, the NOX HeLIUM will never be as fast up climbs as the super-powerful bikes in the Bosch league. However, the much more pertinent question is: how does the NOX HeLIUM handle on the descents? The short answer is: damn well for an eMTB.

With a reach of 470 mm and the relatively long chainstays, the HeLIUM positions its rider centrally in the bike. It keeps your weight balanced, generating equal amounts of grip on both wheels in the corners without requiring of a lot of input from the rider. Regardless of whether you’re hitting a berm or a loose open corner, you can let it rip. The smaller battery doesn’t put as much weight on the front wheel as with most traditional eMTBs. As a result, quick direction and line changes are much easier.

Not only the low weight, but also the support from the suspension makes the HeLIUM easy to get airborne. It invites you to pull manuals and flick out the rear end on jumps. Nevertheless, it still feels composed at higher speeds and instils you with confidence in steep, rough terrain thanks to offering sufficient freedom of movement.

Tuning-Tipp: swap around the matchmakers of the brake levers | 200 mm rotor on the rear

Without the FAZUA unit installed, the HeLIUM’s weight drops to 15.88 kg, which is around 2.5 kg heavier than a comparable trail bike without a motor. Still, the handling was also able to convince us without the motor. It makes the HeLIUM just a little bit more agile, especially on flat, winding trails or on jumps. However, the difference in handling between riding it with and without the FAZUA unit installed isn’t worlds apart.

Conclusion

At 19.81 kg, the NOX HeLIUM 5.9 ALL-MOUNTAIN Pro still isn’t a real featherweight on the scales. On the trail, however, its handling is more direct and playful than we’re used to from traditional eMTBs: the front end of the HeLIUM is much lighter and easier to pull up into the air. It can’t keep up with traditional eMTBs on the climbs, but the NOX HeLIUM is more about letting it rip on the descents.

Tops

  • very agile and intuitive downhill handling
  • modular FAZUA system
  • sensible and high-quality spec
  • super quiet on the descents

Flops

  • no bottle cage bosses
  • speed sensor with a spoke magnet

For more information visit: noxcycles.com

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Words: Felix Stix Photos: Robin Schmitt

About the author

Felix Stix

Felix is responsible for all product testing related content and arguably one of the world’s most qualified technical editors. With a fervent love for tech, a graduate of sports engineering and a vast experience as a qualified bike guide, Felix has all the requisite characteristics when it comes to comprehensive, well-grounded bike testing. His legendary group tests are both loved and feared, but packed with such thorough explanations that no one really minds when they exceed the word count. Testing around 100 bikes per year, Felix has a sharp eye for tires, motors and suspension. Come winter, he tends to shed the bike in favour of skis.