Bosch SX Performance Update

Bosch has unleashed a huge amount of new products this year in the form of new drive units and new updates to existing ones.
In the segment of lightweight e-bike concepts, it has a clear representative, and that is the Performance Line SX drive.

The SX drive unit was the first unit in the Bosch portfolio with a new 2-bolt frame mount. The unit, which came to the market in 2023, has recently received updates in the form of increased torque and assistance.

Before we look at the performance update itself, let's introduce the SXko a little again. The SXko is designed for lightweight e-bike and eGravel concepts. Its tuning corresponds to this, so don't expect any wow effect from the performance here. In short, you have to pedal hard to get the drive to the right speed.

This is the lightest drive unit in the Bosch portfolio, weighing only 2 kg. Since its launch on the market, it has been known mainly for its smooth disconnection when reaching 25 km/h. This feature will be appreciated mainly by owners of gravel and lightweight xc ebikes. It is clear that Bosch has transferred the insights and features of the SX to the new, 5th generation CX drive. Thanks to its focus, Bosch offers the SXko in combination with an integrated CompactTube battery with a capacity of 400 Wh. This is the lightest combination of unit and battery from Bosch. Some customers clearly lacked the capacity for longer trips, which is why Bosch later offered the external PowerMore 250 Wh battery, with which the SX is compatible.

So if you are a sporty user, focusing your choice of e-bike on weight, then you will definitely have the SXko in your sights. Be prepared, however, that if you are not a cadence rider, then this drive may not be entirely suitable for you. I have noticed that the SXko feels nice when your cadence is somewhere around 90-95 rpm.

Let's finally take a look at what Bosch brings in the update. The update, which every owner can download using the Flow app, gives you a new increase in max. torque from 55 Nm to 60 Nm and an increase in percentage assistance from 340% to 400%. Bosch achieved these numbers by tuning the performance curve and adding a new eMTB+ mode, which CX owners could use after the update. With the increase in torque comes a slight increase in energy consumption, but of course everything depends on the riding style. It is up to the owner whether to set the torque increase in the app or keep the same values ​​as before the update. Let's now actually test the differences in the original settings and the new update.

Let's summarize, with the update package, SX owners get a new 60 Nm of max. torque, a max. power of 600 W and 400% assistance. I was originally expecting a bit more power after the CX drive update, like 70 Nm and 650 W, so the drive would be a bit more flexible on technical climbs. But this motor is aimed a bit differently, mainly at gravel categories, where higher power isn't exactly a priority. Thanks to that, Bosch was able to keep the SX's fuel consumption pretty low.

So if you're looking for a lightweight e-bike concept, the SX may now be a slightly better choice thanks to the increased power values.