Flyer Uproc SL Review

It’s light, it’s sleek, and it’s still affordable. The Flyer Uproc SL:X tips the scales at an impressive 17.6 kilos, making the competition look outdated. The only question is: Do the sparsely allocated 130 mm of travel force a compromise that you actually don’t want?

Even though the Flyer Uproc SL:X is not designed as a full-throttle machine for tough enduro descents, the product managers did not skimp on the important points. The Shimano XT brake system with 4-piston calipers and large 203mm discs at the front and rear decelerates really well. It doesn’t matter if you’re grabbing the lever on a steep trail or a forest road. The brakes decelerate more than adequately both ways, ensuring a consistently safe riding experience.

The mechanical 1×12 Shimano XT drivetrain is technologically clearly inferior to the Sram Transmission drivetrain, but during our test, it performed unnoticed. Sure, with a price of over €7000 for the complete bike, you’d prefer a more opulent shifting system, but you don’t have to worry about the fun of the ride. The drivetrain doesn’t diminish the enjoyment at all. And visually, the silver-gray Shimano components perfectly match the frame’s paint job.

Details like the E-bike specific wheelset, small integrated mudguards, or broad and solidly supported bearing seats are not unique features in the market. However, they still make it clear that Flyer applies a certain degree of thoroughness in their development.

The result of this thoroughness is not just a bombproof frame, but a bike that you can enjoy for a long time without major issues. The thoughtful construction keeps coarse dirt out of the small corners of the rear triangle, effectively combating wear and tear.

The cables, which run internally but are not integrated into the headset, can be very easily replaced in case of damage. The mini-tool integrated into the head tube also makes minor repairs on the trail quick and easy.

The Bosch-SX motor is about a kilo lighter than its full-power counterpart (the Bosch CX) and is also slightly more compact. Nevertheless, on paper, it delivers a similar peak performance of 600 watts. This makes the SX motor significantly superior to the motors from TQ and Fazua, although it does come with a major caveat.

When it comes to uphill performance, the Bosch SX only delivers strong support if the cadence is right. While the Bosch CX, the full-power model, provides its maximum output over a wide RPM range starting at around 50 revolutions per minute, not much happens at lower cadences with the SX.

It’s only from 90 revolutions per minute and above that the Bosch-SX motor unleashes its full power. If you can manage that as a rider, the motor impresses with a sporty character and strong support. Simply climbing into the saddle and letting your legs rest on the pedals is not enough to bring the Bosch-SX motor into its desired operating range.

The noise level of the Bosch SX is reminiscent of its bigger brother with a clearly audible whirring whenever you demand power from the motor. We had hoped that Bosch had gotten the gearbox rattle, known from the Bosch CX, but also from the Shimano EP8 or EP801, under control with the SX, but we were disappointed. Here, both the TQ and the Fazua motor are a step ahead.

However, the truth about the Bosch SX system is that you shouldn’t aim to cross the Alps with a 400 Wh battery. Because with sporty riding in Boost mode, even a lighter rider can drain the battery after just over 1000 meters of elevation gain.

If you want to ride longer, you have two options. Either you stay away from Boost mode, or you use the Range Extender with an additional 250 Wh, which can be connected externally. Combining both options makes 2000 meters of elevation possible.

However, the Flyer will never be a range monster. And the fact that the battery is permanently integrated into the downtube and cannot be quickly removed on the trail further reduces the system’s flexibility.

Even though the motor is the heart of an eMTB, the ride characteristics beyond the motor are what count for fun on the trails. The high-quality feel from premium contact points like grips or handlebars is complemented by a super-responsive suspension and strong brakes.

The relatively long main frame aligns with the current market trend, allowing a sporty stance even on the Flyer Uproc. The wide handlebar with a high rise ensures that the saddle doesn’t have an overly aggressive drop. Thus, less trained riders won’t face posture problems on long tours.

Thanks to the stiff frame, the bike handles precisely on the trail. The suspension effortlessly absorbs roots and smaller rocks. You’ll only notice the 130 mm of travel when you take the Uproc SL:X airborne. During hard landings, the limited reserves of the rear triangle and fork become apparent. In wet conditions or extremely rough terrain, the Wicked Will tires also reach their limit.

The bike’s shortcomings only become apparent when you ride it beyond its intended use. On tours with easy trails, it leaves a thoroughly well-designed impression.

With €7,499, our test bike is more affordable than many other models equipped with Bosch’s SX motor. For €5,799, there is also a significantly more price-aggressive model of the Uproc SL:X. With the arrow symbol , you can compare individual models with any other bike from our extensive market overview. Especially intriguing is the comparison with Canyon’s Neuron ON Fly, Scott’s Lumen or the Bulls Sonic Evo AM SL.