NOX HeLIUM 5.9 ALL-MOUNTAIN Pro on test – Hard-hitting, lightweight eMTB with FAZUA motor

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 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 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.

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 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.

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 19.18 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.

For more information visit: noxcycles.com

Here you can find more about the Specialized Levo SL and eMTB light:

• Exclusive first ride review: Specialized S-Works Levo SL 2020 (Click for review)
• Specialized Levo SL vs. Stumpjumper vs. Levo in test (Click for review)
• How the Levo SL is changing the face of mountain biking! (Click for ENDURO article)
• Specialized Levo SL Expert Carbon on test (Click for the ENDURO group test)
• Exclusive Review: Lapierre eZesty AM LTD Ultimate (Click for review)

---

Did you enjoy this article? If so, we would be stoked if you decide to support us with a monthly contribution. By becoming a supporter of E-MOUNTAINBIKE, you will help secure a sustainable future for high-quality cycling journalism. Click here to learn more.

Words: Photos: Robin Schmitt