Bosch has long been known for producing top-tier e-MTB motors, but until recently, they didn’t have a model aimed specifically at the super-lightweight (SL) e-MTB market. Enter the Performance Line SX, Bosch’s answer to riders looking for a balance between power and finesse in a compact package. Now that the drive unit has finally hit dealer floors in 2024, we had the chance to test ride a bike equipped with this highly anticipated system – and it does not disappoint!
Let’s talk numbers
Alright let’s get down to business with the numbers and we’ll begin with the most important ones; power and torque! The Performance Line SX drive unit comes out swinging with 55Nm and a massive 600W of max power. This makes it among the most powerful in the SL category. In fact, it edges out key competitors like Specialized and TQ, which both offer 50Nm. The only motor to surpass it in torque is the Fazua, but even then, the Fazua only hits its 60Nm in short bursts.
When it comes to peak power though, Performance SX dominates all 3 brands that we just mentioned, with it’s whopping 600W, significantly higher than its rivals and in line with most ‘full fat’ drive units on the market which is very impressive indeed!
How much weight and juice are we talking?
How much weight and juice are we talking? The entire drive unit (which is magnesium encased) tips the scales right on 2kg, which is very competitive in the ‘SL’ e-Bike category. For instance, it’s just 150g more than the TQ and 50g heavier than the Specialized and also Fazua options. To fuel the new drive unit Bosch has introduced a brand-new battery to power the Performance SX drive unit, the CompactTube 400. As the name suggests, it has 400 Wh capacity, and weighs in at 2 kg, bringing the total weight of the drive system to just 4kg – which is less than just their standard 750Wh battery alone! For riders that want longer rides Bosch offer a cleverly designed range extender battery which can be plugged into the system to provide an extra 250Wh of juice.
Intuitive Power Delivery
Throughout our test rides one of the standout features I noticed about the Performance Line SX is its smooth and intuitive power delivery. It integrates seamlessly with Bosch’s existing System Controller and Mini Remote, making it easy to control the various modes. The drive unit encourages a high-cadence riding style, making it ideal for those who prefer spinning over mashing pedals. The power tapers off gently as you approach the speed limit, and Bosch claims 50% less resistance than their full-power CX system, giving you a more natural pedalling experience when the drive unit’s assistance fades out.
Customization and Connectivity
As you’d expect, the SX motor is fully compatible with Bosch’s Flow App, allowing you to customize each power mode to your preference. The app also offers security features, diagnostics, and ride tracking, providing a well-rounded and user-friendly experience. Whether you want to tweak the responsiveness of the drive unit or simply track your battery life more precisely, the Flow App gives you the tools to fine-tune your ride.
How does the SX’s numbers compare to the existing Performance CX model?
Good question, stacking the SX to the full power Performance CX system, we’re looking at a total weight saving of approximately 3kg including controllers (Performance CX motor is 2.9kg plus a 750Wh battery weight of 4kg), no reduction in peak power, and 30Nm less torque.
How it rides
How it ridesAs you would expect, the Performance SX proves to be an excellent option for riders who want to push themselves a little more physically compared to the unlimited power and support of a ‘full fat’ drive unit. It’s the ideal drive unit for riders who want a balance of power and rider input. The light weight makes the e-bike feel nimble, while the drive unit’s power delivery is smooth and predictable. One thing that is immediately noticeable when you first head out for a trail ride on the SX drive unit is that the system thrives with a higher than average pedalling cadence. It encourages the rider to spin the cranks in a lighter gear ratio rather than grind revolutions in a heavy gear. I actually much prefer to pedal at a higher cadence as I find it takes less energy, so the SX drive unit was instantly to my liking. Overall, the new SX system lives up to everything we were hoping for in Bosch’s first attempt at a ‘SL’ style motor and it definitely holds its own against the rest of the competition in this market.
Key Details:
Compact, lightweight motor not lacking power!
Drive unit weighs just 2kg
400Wh battery as standard.
Battery weighs 2kg as well.
250Wh range extender battery available
55Nm max torque
600W max power
Smooth and Intuitive power delivery
Customisable modes and extended ‘boost’
Uses Bosch’s existing System Controller and Mini Remote
Great connectivity paired with the Bosch ‘Flow’ App