Also available with belt drive

Lightweight urban e-bike in three styles: Flyer Upstreet SL


Bosch unveiled its new drive system for lightweight e-bikes just yesterday, featuring the Performance Line SX mid-drive motor and a compact battery with 400 Wh capacity. It is hardly surprising that the first bikes are already being presented that use this system and its new possibilities. A prime example of this is the new Upstreet SL from the Swiss manufacturer Flyer!

The elegant urban bike is available in a fully equipped version for everyday use, which includes mudguards, rear rack, lighting system and a kickstand — and yet the bike is said to weigh only about 18 kg. On the one hand, this shows the advantage of the drive system, which weighs only about 4 kg, and on the other hand, of course, Flyer’s experience with the frame and the other components.

Discreetly integrated: Bosch’s new SX drive

Best of all, with its 55 Nm of torque and a battery capacity of 400 Wh, you don’t have to make any significant sacrifices. The electric drive offers more than enough reserves and range for use in urban environments. Equally pleasing: the battery of the Upstreet SL can be removed from the side and can thus be conveniently charged at the nearest outlet — without having to move the whole bike there.

The operation of the drive system is integrated maximum unobtrusively. For this purpose, Flyer installs Bosch’s System Controller on the top tube, with which the drive can be switched on and off and which also displays the riding mode and remaining battery capacity. On the handlebars, the Mini Remote can then be used to change the riding mode and activate additional functions such as lights or push assist. A classic display is therefore not installed ex works — but can be retrofitted as an option thanks to Bosch’s modular system. To be honest, the Upstreet SL’s minimalist and uncluttered look suits it perfectly; and you can also display additional information via Bosch’s Flo app on your smartphone without having to install a fixed display.

Derailleur or hub gears? The Upstreet SL offers both!

While the electric drive is always the same, the Upstreet SL comes in three trim levels:

  • Flyer Upstreet SL 3.10: Here the new CUES system from Shimano is used. This new universal assembly offers a variety of compatible components and is also equipped with the new Linkglide technology. This is intended to ensure harmonious shifting processes and significantly reduced wear, especially on e-bikes. The 9-speed derailleur comes with a mountain-ready ratio thanks to 11-46 cassette. Permanently installed is a lighting system with a FLYER ONE HL-2 headlight with 100 lux and a taillight on the mudguard. In addition, the bike is equipped with a rear rack and the 47 mm wide tires are from Vittoria.
  • Flyer Upstreet SL 3.12 XC: This variant is also equipped with the aforementioned derailleur, but does without mudguards and the rear rack. For this, the bracing is wider again with 52 mm, which promises additional driving comfort. The headlight is also permanently installed here, but the rear light is separate and battery-powered due to the lack of a mudguard.
  • Flyer Upstreet SL 3.63: Here, things are different: this variant looks at first glance like a singlespeed bike — but it is not! Flyer does here without a derailleur, instead, a compact 2-speed hub gear from Classified is used. This drive is combined with a belt drive from Gates instead of the conventional bicycle chain. Apart from that, the rest of the equipment with lights, mudguards and rear rack corresponds to the SL 3.10.


Flyer demonstrates with the new Upstreet SL, how a modern and lightweight urban e-bike can look — without having to sacrifice essential factors. Thanks to a powerful drive, removable battery and extensive equipment, the new bikes leave hardly any wish unfulfilled and are also very pretty to look at! In addition to the diamond frame with a high top tube, the Upstreet SL will also be available with a comfort frame in trapezoid shape in four frame sizes and the two colors Frosty Sage Gloss and Anthracite Gloss.

Prices start at 3,999 euros for the sporty Upstreet SL 3.12 XC without mudguards and rear rack. The commuter-ready equipment of the Upstreet SL 3.10 is only slightly more expensive at 4,199 euros. However, a hefty surcharge is then due for the Upstreet SL 3.63, because this variant is to go on sale for 5,899 euros — which should be significantly due to the special circuit of Classified. The new bikes should be available from spring 2024.




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