Breaking eMTB news from Switzerland: FLYER introduce the 2024 Uproc X 8.70. It’s marketed as an all-rounder, promising to excel at everything from flowing single track to the occasional bike park visit, as well as all-day rides in the picturesque Swiss Alps. But can the FLYER Uproc tick all the right boxes and deliver on this promise?

FLYER Uproc X 8.70 | Bosch Performance Line CX/750 Wh | 150/150 mm (f/r) | 29″/27.5″ (f/r) | 25.1 kg (size M) | € 7,999 | Manufacturer’s website

The Uproc series is a firm fixture in FLYER’s portfolio. It all started in 2014 with the FLYER Uproc 6. Since then, FLYER have regularly introduced new iterations and models, and we’ve always reviewed them. The last one, the FLYER Uproc EVO:X 9.50, was presented less than a year ago. Besides the name, the only thing all FLYER models have in common is the fact that they’ve got an electric motor. The Uproc series doesn’t even remain true to a specific motor brand. That said, FLYER predominantly rely on Bosch motor systems, as with their latest bike on test. However, they have also used more exotic motors from the likes of Panasonic. The intended uses also vary from relaxed touring to big hits and fast descents, which is reflected in the suspension travel. The newly introduced 2024 FLYER Uproc X 8.70 is designed to be an all-rounder, offering 150 mm travel front and rear. But the first FLYER still has one other thing in common with today’s. They’re all based on a mullet setup, i.e. a smaller wheel at the rear than up front. In 2014, however, it was a 27.5″ wheel at the front, paired with a tiny 26″ wheel at the rear. Today, the Uproc rolls on a large 29er up front, and a 27.5″ rear wheel. In terms of price, FLYER have become a little bit more reasonable, asking € 7,999 for the 25.1 kg flagship model.

The 2024 FLYER Uproc X 8.70 in detail

The Uproc has undergone many changes over the years, and not much remains of the original aluminium bike. The 2024 FLYER Uproc X 8.70 features a modern, full carbon frame with straight edges and distinctive lines. Only the internal cable routing has remained unchanged. Just like in 2014, the cables enter the frame via ports behind the head tube – not through the headset. They remain hidden in the frame without rattling until they reach their destination. The large rubber pads on the chainstays and seat stays also help to keep the peace, effectively damping the chain.

An increasingly common, yet still far too rare feature on eMTBs is hidden tools. You’ll find a small multi-tool from Granite in the head tube of the FLYER, which features a T25 in addition to the most important hex key sizes. They’ve also hidden a 6 mm Allen key in the rear thru-axle. That way you’ll never forget your multi-tool at home, and won’t have to cancel your ride because of a minor issue.

But that’s not all. Thanks to the two MonkeyLink mounts, you can simply clip lights to your Uproc and safely head home in the dark or use it for commuting.

The internal cable routing relies on classic cable ports on the frame instead of being routed through the headset.
Simply clip on your lights and continue riding safely in the dark, whether on a lonely dirt road or in the city bustle.
The small multi-tool in the headset is always on hand to help you out in a pinch.

The motor system of the 2024 FLYER Uproc X 8.70

For the motor, the Swiss brand rely on the Bosch Performance Line CX. The 85 Nm motor is powered by a 750 Wh battery, which you can slide out of the bottom of the down tube of the 2024 FLYER Uproc X 8.70. You must simply loosen one screw to remove the battery, making it easy to charge in your living room if you don’t have a power outlet in your basement or garage. To make this possible, the development team positioned the motor at an angle, freeing up the bottom of the down tube. Of course, you can also charge the battery in the bike. The charging port is easily accessible in the front triangle, sitting on the seat tube just above the motor. With the Bosch PowerMore range extender, the FLYER is also prepared for long day trips where the 750 Wh battery capacity could get tight. That gives you the option of expanding the total battery capacity by 250 Wh. The motor system is rounded off with the cordless Mini Remote on the handlebar, the minimalist Bosch System Controller in the top tube, and the Bosch Kiox 300 display to the left of the stem. Furthermore, the Bosch Smart Systems makes life more difficult for would-be thieves, so you can enjoy a refreshing Rivella on an alpine pasture with added peace of mind. That’s thanks to the eBike Lock function, allowing you to lock the motor via Bluetooth. What’s more, you can track your FLYER via the Bosch Connect module, which comes fitted as standard, though you need to have the function unlocked.

The Bosch Kiox 300 display is positioned next to the stem where it’s nicely protected.
The charging port is easily accessible from any side.
After loosening a single screw, the battery can be pulled out of the bottom of the down tube. The motor has been tilted slightly to make this work.

The components of our 2024 FLYER Uproc X 8.70

When speccing the Uproc model on test, FLYER tried to combine affordability with maximum functionality. This is underlined by the FOX Performance suspension. Up front, you get a FOX 36 Performance fork with the GRIP damper, paired with a FOX FLOAT X Performance shock at the rear. Both offer easy adjustability and perform commendably on the trail.

The shifting is taken care of by a 12-speed mechanical Shimano XT drivetrain. It suits FLYER’s value for money concept to a tee. The four-piston brakes also come from the Shimano XT range. Combined with 203 mm rotors, they provide sufficient braking power even on long Swiss mountain descents.

The FOX Performance suspension is easy to adjust and offers good trail performance.
The four-piston Shimano XT brakes and large 203 mm rotors provide ample stopping power.

For the tires, FLYER keep things local by relying on fellow Swiss company ONZA. On the ONZA PORCUPINE to be precise, featuring the Trail casing at the front, and the thicker Gravity casing at the rear. Unfortunately, the PORCUPINE tires weren’t yet available, so the sturdy DT Swiss H1900 mullet wheelset was fitted with the more aggressive Onza Aquila tires featuring the GRC casing for the purposes of this test.

The SATORI Ursa stem is bolted to an 810 mm wide Hayes ProTAPER carbon handlebar. However, we find 810 mm too wide for a frame size M. That’s why we shortened it to 780 mm for our review. On the other hand, the 150 mm KS Lev Integra dropper post offers too little drop for a modern eMTB, even in size M, and severely restricts your freedom of movement.

We shortened the very wide 810 mm handlebar to 780 mm.
Unfortunately, the dropper post restricts your freedom of movement, offering just 150 mm drop.

Tuning tip: volume spacer in the fork for more progression

FLYER Uproc X 8.70

€ 7,999


Motor Bosch Performance Line CX 85 Nm
Battery Bosch PowerTube 750 Wh
Display Kiox 300
Fork Fox 36 Performance GRIP 150 mm
Rear Shock Fox Float X Performance 150 mm
Seatpost KS LEV Integra 150 mm
Brakes Shimano XT 203 mm
Drivetrain Shimano XT 1x12
Stem Satori Ursa 35 mm
Handlebar Hayes ProTaper Carbon 810 mm
Wheelset DT Swiss H1900 29"/27.5"
Tires Onza Porcupine, TRC/Onza Porcupine, GRC 2.4"/2.6"

Technical Data

Size S M L XL
Weight 25,1 kg

The different model variants of the 2024 FLYER Uproc X 8.70

In addition to the model on test, FLYER are offering two more affordable versions, as well as a limited special edition at the same price as the tested flagship model. All versions rely on the same motor system, though the entry level FLYER Uproc X 2.10 for € 5,999 has to make do with a smaller 625 Wh battery. For the suspension, this model comes fitted with a SR Suntour AION36 fork, combined with a RockShox Deluxe Select shock. You get a pair of two-piston MAGURA MT4 brakes to keep your speed in check. For the wheels, FLYER combine DT Swiss H552 rims with Formula hubs.

One up from that, you can get the mid-range version for € 6,999. The FLYER Uproc 6.10 comes with a FOX 36 Rhythm fork and a RockShox Deluxe Select shock. The brakes are upgraded to four-piston MT5s.

The limited edition model boasts FOX Factory suspension with the golden Kashima coating. However, this comes at the cost of other components, like an XT/DEORE mix instead of a pure XT drivetrain.

The geometry of the 2024 FLYER Uproc X 8.70

The 2024 FLYER Uproc X 8.70 is available in four sizes from S–XL. Our size M test bike had a fairly slack head angle for an all-rounder, measuring 64°. At 465 mm, the reach is on the longer side too, with a considerable 30 mm difference between sizes. While this allows FLYER to cover a wide range of riders, it increases the likelihood of being caught between two sizes, neither of which really fit. The chainstays remain static at 445 mm, which is relatively long and reflected in the wheelbase. The 408 mm seat tube is pleasantly short, which provides abundant freedom of movement, provided you’ve got a long-travel dropper post fitted.

Size S M L XL
Top tube 567 mm 600 mm 632 mm 664 mm
Seat tube 388 408mm 438 mm 483 mm
Head tube 95 mm 110 mm 125 mm 140 mm
Head angle 64° 64° 64° 64°
Seat angle 75.5° 75.6° 75.7° 75.8°
Chainstay 445 mm 445 mm 445 mm 445 mm
BB Drop 35 mm 35 mm 35 mm 35 mm
Wheelbase 1,210 mm 1,246 mm 1,283 mm 1,319 mm
Reach 435 mm 465 mm 495 mm 525 mm
Stack 611 mm 624 mm 638 mm 652 mm

The 2024 FLYER Uproc X 8.70 on the trails

If you grab the 2024 FLYER Uproc X 8.70 to set off on your next eMTB tour, it will welcome you with a comfortable and upright riding position. It’s perfectly suitable for touring and long days in the saddle despite being slightly hand-heavy. You benefit from this on the climbs where you always have enough weight on the front. The front wheel stays planted even on the steepest gravel road you can find on your Swiss mountain retreat. The Bosch Performance Line CX motor provides heaps of support regardless of your pedalling cadence.

Even if the last few metres to the summit consist of technical single track, the FLYER will perform convincingly. Thanks to the balanced handling, the Uproc lets you stick your line, navigating up ledges and over roots with ease. The rear suspension remains active, generating sufficient traction and comfort.

When you hit the descent after a short break and a piece of carrot cake at the mountain inn, you’ll quickly feel comfortable aboard the bike, as the intuitive handling doesn’t take long to get accustomed to. The suspension of the FLYER Uproc X is beautifully balanced between firm and plush. This makes the bike excel on natural trails, offering a good compromise for both trail riding and tours.

The initial suspension setup doesn’t require a whole lot of nerdery, with the basic setup easily absorbing big impacts while still offering plenty of feedback from the trail, which is especially beneficial for less-experienced riders. That said, the fork is clearly lacking in progression. On bigger drops, the front end tends to dive, which can rob you of confidence. A volume spacer in the fork should remedy this.

The Uproc X performs particularly well in dry and grippy conditions, while muddy and loose terrain pushes the tires to their limits. In situations like these, they quickly lose grip and often slide out abruptly. Nevertheless, the Uproc X shines as an all-rounder on well-established routes, though the amount of fun you can have on very steep sections is somewhat limited due to the fork. Rather than the kind of bike that encourages to keep going faster and tackling ever more demanding trails, it’s faithful companion on familiar routes thanks to sensible features like brackets for lights and an integrated multitool.

Who is the 2024 FLYER Uproc X 8.70 for?

The 2024 FLYER Uproc X 8.70 is for all riders who like tackling steep climbs with the help of a powerful motor, or climb to a lonely mountain inn on technical single track. On the descents, it delivers with its intuitive and good-natured handling, appealing to anyone who hasn’t got a need for speed, aiming to win the next eMTB race at the weekend. Rather, it’s a reliable and fun companion for most trails and long rides. Thanks to the integrated light mounts and multi-tool in the head tube, it can also serve those who want to use their eMTB as a commuter.

Our conclusion on the 2024 FLYER Uproc X 8.70

At first glance, the 2024 FLYER Uproc X 8.70 seems like a good deal and a decent build. And it stands up to closer scrutiny, too, offering fun handling and excellent on-trail performance. As such, It should appeal to a wide range of riders, and it’s got everything you need for long, all-day epics, including ample comfort and a powerful motor. All in all, you get a well-specced and beginner-friendly build for a fair price of € 7,999.


  • beginner-friendly handling
  • hidden tool in the steerer tube
  • good all-rounder


  • fork lacks progression
  • short dropper post

For more information, visit the FLYER website.

The predecessor didn’t fare that well in our last group test. But how would the current FLYER Uproc X 8.70 stack up against 27 of the latest and greatest eMTBs on the market?

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Words: Sebastian Dirscherl Photos: Peter Walker