Bosch joins Shimano in offering ABS braking systems for electric bikes, plus new 'hill hold' feature.


Bosch has created an ABS system for e-bikes that effectively stops the front wheel from skidding out of control. The technology is available across loads of different disciplines, from cargo to commuter, but obviously we’re interested in the Trail version for mountain bikes.

There are several components to the system, with a Magura disc brake handling the physical stopping part, and a Bosch black box on the left fork leg housing the computer. The regular brake rotor is supplemented front and rear by an extra rotor bolted to it, and there are sensors reading the wheel speeds from those additional rotors. It’s all tied together with a chunky looking cable that houses a wire. The brake lever looks pretty familiar to us, but the top of the reservoir has an extra cover screwed to it.

How the Bosch eBike ABS works

Bosch eBike ABS works by sensing the speed of both wheels. When the wheel stops turning the braking force is automatically reduced by the system’s algorithm, before the force is increased again for maximum stopping force, and so on. Bosch says you’ll get more grip on slippery sections and will be less likely to go over the bars too.

Two mountain bikers riding with Bosch eMTB motors

If you’re feeling a strange sense of deja vu, don’t panic, you’re not stuck in the Matrix. The German motor experts actually launched a similar system just five years ago, albeit with no discernible take up from the industry. Bosch says the new tech is 77% smaller and 55% lighter than the old version, coming in at a claimed 277g for the ABS box and 402g for the entire system including cables, rotors, mounts etc.  

A nice little bonus is you can get all kinds of data analytics on the Kiox 300 display to better understand your braking, such as information on braking distance or braking time. Most of us here are guilty of comfort braking or dragging our brakes sometimes, so we’d be very interested to see how to improve.

It’s not the only new thinking from Bosch in this cornucopia of tech; the brand has fixed many of the bugbears we’ve had with the CX Performance Line systems.

At last, the display has left its obtrusive position on the handlebar and now integrates in a bike’s top tube. There are colour-codes for each of the power modes, and five LEDs to indicate how much battery level you have remaining: if they all light up ice blue, the battery is 100 percent charged. If an LED turns white, this means the charge level has decreased by ten%. There are two soft-touch buttons, and the screen now has an ambient light sensor to automatically adjust its brightness.

The bar mounted remote hasn’t disappeared entirely though, it’s replaced by a much smaller Mini Remote. It’s no where near as diddy as some of the competition, but you can remove it entirety now and just flick through the modes on the top tube controller. There are three buttons on the Mini Remote, mode, a light, and Walk Assist. Bosch has tweaked the latter too, the motor now has something called Hill Hold – release the Walk Assist or stop pushing up and the bike will hold itself stationary for 10 seconds.

Mountain bikers pushing eMTBs uphill with the new Bosch Hill Hold mode

No need to worry about the bike rolling away from you now

New ‘hill hold’ feature

There are a few other updates to the Bosch electric mountain bike offering, including the new ‘hill hold’ setting. Working with the ‘walk assist’ mode, which helps when you need to walk or push your bike up hills, ‘hill hold’ prevents the bike rolling back downhill if you stop.

It’s triggered if the rider changes their grip on the bars or stop pushing, and locks the wheels without having to apply the brakes. The bike will then stay in ‘hill hold’ mode for ten seconds before deactivating, or will automatically deactivate when the bike is pushed forward again activating ‘walk assist’ mode.

But do we need ABS braking and automatic shifting?

From ABS to the automatic shifting systems Shimano has just unveiled, we’re talking about e-bike tech here, and it’s hard to argue that pedal assisted riding isn’t at the cutting edge of mountain biking. 

The big question though, are these developments welcome? We reckon anything that takes away the boring parts, or even the less exciting parts of the sport, is a good thing.

Tubeless tyres prevent flats, electric shifting makes changing gears more reliable, and dropper posts mean you don’t have to stop and put your saddle down. All easy wins. Shimano’s auto shifting fits into that line of argument, because, well, I don’t ride my bike for the joy of thumbing up and down the cassette.

Bosch’s ABS however is less clear cut. Releasing those levers across roots and off-camber sections, judging where to brake and how hard, not braking in corners – this is mountain biking. It’s a skill that feels great when you get it right. Take it away and we’re effectively just rolling down fireroads. 

Don’t write it off just yet though, as we’ve no doubt ABS is going to be faster for racing because you can break in previously impossible areas and thereby maintain a higher average speed.

There’s also a huge grey area of technology, where improvements to your bike make riding easier but also more fun – suspension, 29in wheels, grippy tyres. They’ve all given us a big step in terms of what we can ride, and how fast we can ride it, and ABS brakes could do exactly the same thing.

What we do know is this – there’s no putting that genie back in the bottle.