Giant SyncDrive Pro 4: Lightweight e-bike motor with 120 Nm and 850 watts

As in previous years, Giant is forging its own path when it comes to e-bike motors. The new Syncdrive Pro 4 and the Giant E+ system surrounding it set new benchmarks in many respects in their latest iteration. This starts with the basic concept. Until now, the hardware of the Syncdrive drives had been identical to that of the Yamaha units. With this new model, not only has the software been adapted, but the motor housing has too. It is this bespoke design that makes the kinematics of the new e-mountain bikes from Giant and its sister brand Liv possible in the first place. With the Giant Trance Advanced E+ and the Liv Intrigue Advanced E+ There are two bikes fitted with the new engine ready to go.

Giant specifies a maximum torque of 120 Nm, a peak power output of 850 watts and up to 500 per cent assistance for the SyncDrive Pro 4. This makes the new motor one of the absolute most powerful e-bike motors on the market, second only to Avinox’s super-powerful motors. The motor sets a new benchmark in this class for weight. Giant states that the motor weighs just 2.4 kilos. A figure we have not yet been able to verify independently. That would be 200 grams lighter than an Avinox M2S and 400 grams lighter than a Bosch CX. Already The Syncdrive Pro MG, the lightest in its class, made headlines in the BIKE test. The new model is not only even lighter, but, above all, significantly more powerful.

The facts about the Giant Syncdrive Pro 4

One distinctive feature of the Giant and Yamaha drive systems remains in this new version. The Pro 4 responds to pedal pressure before the crank even moves. The manufacturer cites assistance from zero revolutions per minute and a response time of 0.28 seconds. We’re already familiar with this immediate engagement from previous generations, and it’s a huge help when setting off on steep terrain. The start-up and engagement behaviour can be customised in the app. Even in their factory settings, the high-power modes are very direct, whilst the lower levels are designed to be more subtle. This effectively prevents the jerky twitching that occurs when your foot touches the pedal – something that can be rather annoying in everyday use.

Giant also promises powerful performance on long climbs without overheating. According to the manufacturer, this is made possible by the 48-volt system, more heat-resistant internal components and thermal management via the Smart Gateway. Whether the motor is actually this reliable under sustained load and heat remains to be seen in an independent test.

Sensors and Traction Control: How to get the power onto the trail

The level of assistance provided by the SyncDrive Pro 4 does not depend solely on a fixed setting. According to the manufacturer, Giant’s ‘Synchronised Power Matrix’ takes six factors into account: torque, cadence, speed, gradient, power and acceleration. There are no fewer than six modes to choose from – that’s plenty: Eco, Tour, Active, Sport, Power and Boost. Using the RideControl app, you can adjust the assistance level, responsiveness and follow-through, amongst other things; custom profiles are also available.

On loose terrain, Traction Control is designed to detect rear-wheel slip and reduce motor assistance accordingly before it increases again. According to Giant, the system analyses speed, gradient, cadence and torque to do this. This function can be switched on and off in the app – uniformly across all modes. In practice, the traction control is noticeable. On very difficult climbs, however, the reduced power output when slippage occurs can also become a problem, as the reduced assistance disrupts the flow of the climb. We would therefore have liked the option to adjust the traction control setting individually for each level. Perhaps Giant will make further improvements to this aspect in the app.

EnergyPak 840 and optional range extender

On the new Trance Advanced E+, a removable EnergyPak Smart 840 powers the motor. Giant specifies a capacity of 840 Wh, a weight of 3.7 kilograms and an energy density of 375 Wh per litre. This is an excellent figure, which also makes for a really lightweight complete bike. Anyone needing extra capacity can attach the separately available EnergyPak Plus 280 to the bottle cage mounts. This increases the nominal total capacity to 1,120 Wh; according to Giant, the additional battery weighs 1.5 kilograms.

Display and control lever of the new E+ system

The SyncDrive Pro 4 system includes the RideControl Go Lux mounted on the top tube. This colour display shows, amongst other things, the battery level, estimated remaining range, speed and cadence. In conjunction with the built-in tyre pressure sensors, it also displays the front and rear tyre pressures. A Smart Gateway connects the motor, battery, display and controls. System updates can be carried out via the RideControl app.

Controls are handled by the wireless RideControl Ergo 5 on the handlebars. Its buttons can be customised and, with the appropriate equipment, can also operate functions such as the electronic Vario seatpost or electronic gear changes.

First impressions of the drive

The new Giant motor feels powerful! The strong thrust at low cadences is particularly noticeable straight away, which is a sign of high torque. Admittedly, the motor clearly can’t keep up with the incredible power of the Avinox motors. However, based on our first few rides, we consider it to be fully on a par with the rest of the market.

Another distinctive feature is the ability to start off straight away from a standstill. Giant calls this ‘Zero Cadence’ – and you can really feel it. With the right setting, the motor kicks in the moment you place your foot on the pedal. This is particularly helpful when setting off in tricky situations.

The thrust remains refined and does not overwhelm the rider. The adjustable follow-through allows you to fine-tune the riding feel and modulation to suit your personal preferences. Incidentally, this applies to a great many parameters that can be adjusted via the app for each assistance level. However, this was not yet possible during our initial test. In the factory setting, the Syncdrive Pro 4 proved to be refined and easy to control. However, for our taste, it lacked that final touch of refinement and responsiveness needed to outperform the top motors from Bosch and Avinox in this category.

Without any weaknesses?

However, we cannot find any serious faults with the handling, the power delivery or the power output itself. In our view, the biggest weakness is the noise level. The drive noise is slightly more noticeable than on the best models on the market. Even at low assistance levels, the electronic whirring is always clearly audible. Bosch and, above all, Avinox do this much better. Even when riding downhill, the Syncdrive motor – just like its predecessor and many other motors – is audible. This is because it rattles from the gearbox. To put this into perspective, it’s worth noting that, in our tests, the only high-output motors that are completely rattle-free are the latest Bosch units.

We were really impressed by the new Ride Control Ergo 5 lever. The buttons have a very precise feel and the ergonomics are excellent. The combination with the brand’s own wireless seatpost is a unique selling point that ensures a clean cockpit and works perfectly from an ergonomic point of view.

Strengths and weaknesses

Strengths

• Lightweight and strong
• refined coordination
• A truly brilliant ecosystem with lightweight batteries and clever features

Weaknesses

• background noise