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Flyer Discovers the Lightweight with the Uproc SL:X

Flyer Uproc SL:X ebike

Orbea has just set a remarkable example with the Rise for the 2025 season when it comes to how little a full-suspension e-mountain bike with a full-power motor can weigh. For any model that appears at the same time and also wants to be categorised as ‘light and powerful’, the comparison will be pretty tough. The new Flyer Uproc SL:X is currently experiencing this. Nevertheless, in our opinion, it does a respectable job.

In fairness, a comparison with the Flyer Uproc X, which is also still quite new, would be more appropriate. This expanded the manufacturer’s all-mountain segment in February of this year. With its Bosch Performance Line CX, it forms a counterweight to the other models in the Uproc series powered by the Panasonic GX Ultimate. The Uproc X and Uproc SL:X are therefore essentially part of the same family. However, the newcomer sets its very own accents, so that it deserves to be considered a model in its own right.

Flyer Uproc SL:X ebike
Flyer Uproc SL:X

Under 20 kg for the first time with an eMTB

Just one look at the scales shows that the Flyer Uproc SL:X occupies a special position in the Swiss company’s range. At around 18 kilograms in its lightest – and also most expensive – configuration, it is by far the lightest e-mountain bike to leave the halls at the headquarters in Huttwil. Compared to the Uproc X, this represents a weight saving of eight kilograms. Although both ebikes are based on a carbon frame, the reasons for the lower weight obviously lie elsewhere.

The first factor in this calculation is definitely the Bosch Performance Line SX. The motor of this drive alone saves around 900 grams. The difference between the various batteries is more than two kilograms. The Flyer Uproc SL:X has a Bosch CompactTube 400 with 400 watt hours. In contrast, you get the Flyer Uproc X with a Bosch PowerTube 750 with 750 watt hours.

Bosch Performance Line SX motor on the Flyer Uproc SL:X ebike
Bosch Performance Line SX motor

Smaller battery not an issue

The lower overall weight of the Uproc SL:X is therefore traded for a less powerful motor and a shorter range. However, the drive doesn’t support you that much shorter. After all, the motor only reaches its peak output of 600 watts at much higher pedalling frequencies than a Bosch Performance Line CX. Together with the lower torque of 55 Newton metres, this means that the Bosch Performance Line SX consumes less energy. At least as long as you mainly stabilise at cadences of around 70 revolutions per minute or less. In addition, the motor moves the aforementioned eight kilograms less from the ground up. All in all, the difference in range probably amounts to around a third of the distance that a Flyer Uproc SL:X lags behind a Flyer Uproc X under otherwise identical conditions.

Flyer saves a display on the Uproc SL:X. The drive on the bike can be operated via the System Controller integrated in the top tube together with the Mini Remote located on the handlebars. The frame is designed for the addition of a Bosch PowerMore 250, and with the Bosch Range Extender you can close the gap in range to the Uproc X completely if you wish.

Bosch System Controller control unit on the Flyer Uproc SL:X ebike
Bosch System Controller control unit integrated in the top tube
Bosch PowerMore 250 range extender on the Flyer Uproc SL:X ebike
The Flyer Uproc SL:X 9.50 and Flyer Uproc SL:X 8.70 models come with the Bosch PowerMore 250 as standard.

Goodbye mullet setup

Surprisingly much has been done to the frame and around it. For example, the manufacturer has dropped the concept of a larger front wheel and smaller rear wheel. Instead, it has fitted 29-inch wheels to both the front and rear of the new model. It’s almost a bit of a shame, as this takes away some of the agility of the lighter bike. Perhaps the large wheels are intended to compensate to some extent for the shorter suspension travel. While the suspension fork and shock on the Uproc X still had 140 millimetres of travel, both components only give way by a maximum of 130 millimetres. Due to this decision, the Uproc SL:X is somewhere between a cross-country bike and an all-mountain bike.

You can influence the direction in which the pointer deflects. A flip chip placed on the handlebar allows you to switch from a low position to a high position and vice versa. In the ‘High’ setting, the bottom bracket is raised by eight millimetres to a height of 344 millimetres. At the same time, both the seat angle and the head angle become slightly steeper. This change gives you a position on the bike that increases your pedalling efficiency, allowing you to save energy and tackle longer tours. The advantage of the ‘Low’ position is a lower centre of gravity, which makes riding downhill easier.

Flip Chip on the Flyer Uproc SL:X ebike
Flyer has placed the Flip Chip on the rocker arm.

Other changes compared to the Uproc X are the slightly simpler shock rocker arm in the form of a supported 1-link suspension with flex pivots and the Flexstay. Behind the latter is a special carbon structure that replaces the bearing that would otherwise be expected there. Such solutions now work very reliably, reduce weight and require no maintenance.

Flyer Uproc SL:X ebike
Due to its low weight and 130 millimetre suspension travel, the Flyer Uproc SL:X is particularly suitable for extended tours on flow trails.

Four models, but only one colour

As with the Uproc X, Flyer is also launching the Uproc SL:X in four different configurations. As usual, the decisive gradations extend to the suspension system, the gears and the brakes. The spectrum ranges from a 12-speed Shimano Deore derailleur, TRP brakes and an X Fusion suspension system on the entry-level model to a Sram XX Eagle Transmission, Shimano XTR brakes and suspension elements from the Fox 34 Float Factory range on the top model. The resulting price difference of € 4,200 between the Flyer Uproc SL:X 4.10 and the Flyer Uproc SL:X 9.50 also includes details such as carbon handlebars with a Monkey Link interface for the front light and a multi-tool integrated into the stem.

According to Flyer, the Uproc SL:X is available immediately. In terms of colour, you have the choice between Cast Silver Gloss and Cast Silver Gloss. Or you can go for Cast Silver Gloss 😉

Monkeylink interface on the stem of the Flyer Uproc SL:X ebike
With the Monkeylink interface on the stem, you can use the Supernova M99 Mini Pro, for example.

Flyer Uproc SL:X 2024 at a glance

  • Variants: Uproc SL:X 9.50, Uproc SL:X 8.70, Uproc SL:X 6.50, Uproc SL:X 4.10
  • Frame: Carbon
  • Suspension fork: Fox 34 Float Factory, Fox 34 Float Performance, Fox 34 Float Rhythm, X Fusion E-Slide 34 RC
  • Motor: Bosch Smart System Performance Line SX
  • Battery: Bosch CompactTube 400
  • Control unit: Bosch System Controller & Bosch Mini Remote
  • Drivetrain: Sram XX Eagle Transmission, Shimano XT, Sram GX Eagle Transmission, Shimano Deore
  • Brakes: Shimano XTR BR-M9120, Shimano XT BR-M8120, Shimano BR-MT520, TRP Slate Evo
  • Weight: from 18 kg
  • Maximum permitted total weight: 130 kg
  • Colour: Cast Silver Gloss
  • Prices: from 5.799 Euro
Flyer Uproc SL:X 6.50 ebike

Pictures: Flyer AG

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