Flyer Uproc SL:X E-MTB Light 2024 Review

Just in time for the season opener, the Swiss E-Bike experts present their light and agile E-MTB Uproc SL:X. With its lightweight carbon frame, the new Bosch Performance Line SX motor, and selected components, the trail full-suspension bike weighs just under 18 kilograms and is aimed at everyone who is looking for a sporty E-mountain bike with a natural riding feel.

The new Bosch SX is a minimal-assist motor that supports up to 55 Nm of torque. It is considered quite quiet and offers a comparatively high peak performance with 450 watts continuous load and a maximum of 600 watts. The technical structure of the SX is the same as the CX, but a third reduction stage was omitted for size and weight reasons. Due to the different primary gearing, the efficiency range shifts upwards and the rider has to maintain a higher pedaling frequency to exploit the full power.
As a result, besides the outer width of the motor housing, the Q-factor also shrank from 178 mm to 160 mm, which comes closer to riding a bio-bike. Nevertheless, the dimensions of the SX remain significantly larger than those of other E-Bike Light motors (Fazua, Bafang, Maxon, and TQ), making an almost invisible integration of the motor system not possible.

"The Uproc SL:X handles like a mountain bike without a motor, but has the necessary boost for plenty of uphill flow", says Philipp Suter, Head of Product Management at FLYER.

"The Uproc SL:X handles like an 18 kg bio-mountain bike with a low center of gravity", we say, but nonetheless: "The kinematics invite active biking and appeal to sporty riders, switchers, and everyone who doesn't want the motor to do all the work", Suter continues. True.

The Uproc SL:X runs on 29-inch wheels, features 130 mm of travel, and has an agile geometry for maximum fun on the trail. Additionally, the kinematics can be adjusted via a flip-chip into two positions (High or Low) and the carbon rear construction allows for subtle flex without additional bearings.

The Uproc SL:X is available in four specifications and in the frame color "Cast Silver Gloss" starting from a recommended retail price of 5,799 Euros. The two top models come equipped with the Bosch "PowerMore" battery in a water bottle format and an integrated multi-tool in the stem from the factory. All four bikes incorporate the practical Monkey-Link interface for the front light; the headlight is directly clipped onto the stem and draws power directly from the Bosch battery.

Tech Specs Flyer Uproc SL:X 9.50

* The cockpit of the model 9.50 is equipped with a practical multi-tool.

Both geometry and kinematics can be adjusted on the Flyer Light E-MTB via flip-chip to suit the riding style and terrain. If necessary, you can switch from the high to the low position in no time, with a flatter steering angle and lower center of gravity.

Additionally, the special carbon layup of the rear frame offers extra flex without complex pivot points in the area of the rear axle.