Good braking is essential for both the safety and performance of your eMTB. Together with MAGURA, Bosch claim to have developed an ebike ABS that promises to make touring safer while helping trail riders improve the riding position and performance of their eMTB. Read our first ride review to find out what the new system is capable of and what its limits are!
Imagine hitting a jump with your eMTB, grabbing both brakes in the air and landing with your front and rear wheel locked out. With normal brakes, this would sound completely absurd and be very dangerous to boot, but that’s exactly what we did with the new Bosch eBike ABS, bringing us safely to a halt. Now, this is by no means a normal situation, but it proves how capable, versatile and clever the new Bosch ABS can be.
Absurd but technically possible – landing a jump with the brakes pulled tight. The Bosch eBike ABS prevents the front wheel from locking.
Once an innovator, always an innovator: from car ABS to ebike ABS pioneer – the 2023 Bosch eBike ABS
Electronic anti-lock braking systems are a standard feature on motor vehicles. They’ve been preventing your tires from locking out during hard braking manoeuvres for decades and make our roads a whole lot safer. Bosch was and still is a pioneer in this domain, and the first patent that Bosch filed on this technology in 1936 came from company founder Robert Bosch himself. In 2018, Bosch introduced an electronic ABS for touring bikes, which was crowned the Design & Innovation Award Pioneer in the year that it was launched. So far, however, the system has been living a niche existence and couldn’t yet gain a foothold on the market. The first generation ABS was too bulky to be successful on the market. Moreover, the smart brake system was reserved for city and trekking bikes with 700C wheels. Now Bosch have launched the second generation of the braking system for their Smart System motor. The new system is 77 % smaller and only about half as heavy as its predecessor. It isn’t just significantly sleeker and inconspicuous, but it also promises to be a lot more capable technically. The new Bosch eBike ABS is no longer reserved for touring and trekking bikes either as they’re also targeting trail riders with the new system. The new eBike ABS is intended to improve the riding position on your eMTB, make rides safer in technically demanding terrain and even allow active manoeuvres such as nose manualing to swing your rear wheel around a tight bend. Will this help Bosch achieve the market breakthrough they’re hoping for?
What’s wrong with modern eMTB brakes?
Modern eMTB brakes can be very powerful. This is a good thing, but it’s dangerous, too – especially with so many newcomers to the eMTB scene that haven’t had a lot of time to get used to modulating the brakes with one finger. Beginners can often be surprised by the braking power offered by hydraulic disc brakes with large rotors. If you brake too hard on slippery surfaces, such as on gravel roads, wet paving or muddy forest floors, the front wheel can lock out. In the worst case, you’ll slip and fall. When braking too hard on a grippy surface, in which case the front wheel locks out but doesn’t slide, your rear wheel can lift off the ground, catapulting you over the bars. According to their own accident research, Bosch estimate that around 29 % of all ebike accidents could be avoided or at least reduced by a reliable ABS
Breakdown of the 2023 Bosch eBike ABS
For the market launch of the new ebike ABS, Bosch have once again teamed up with brake specialists MAGURA. The MAGURA MT C brake levers are designed to push a lot of oil through the lines, which should make them more powerful. For the launch, they’ll be offering two versions, one with a long two-finger brake lever and one with an even longer three-finger lever, neither of which is particularly ergonomic nor features any of the adjustment options that you get with MAGURA’s flagship range. The brake calliper is based on the MAGURA MT5 four-piston model. There will also be a variant with a two-piston calliper. Note: the brakes determine the feel of the brakes, not the ABS. There’s a slotted sensor disk attached to the brake rotor called the tonewheel, which is used to determine the wheel’s rpm. The actual ABS is located in a small box clamped to the left fork leg. At a press camp, however, we saw the first suspension forks featuring a post-mount attachment for the ABS box. It’s not just the brake line of the front brake, but also the electric cables of the front and rear sensors that are fed into the black box. This means you’ve got more cables cluttering the front of your bike, but it’s a significant improvement over the previous version. The system is powered by the main ebike battery. It consumes such little power that it makes no noticeable difference to your range and the ABS remains active even if the battery has run too low to power the motor. Fortunately, the big indicator light of the first generation ABS is gone. Instead, the new ABS relies on an indicator on the LED remote and the KIOX 300 display.
The theory behind the 2023 Bosch eBike ABS
If you turn on the motor, the indicator light turns on briefly and then turns off again, like the ABS light on the dashboard of your car. When the indicator light is off, it means the system is active. The system detects the braking situation via several sensors. It determines your travelling speed and the rpm of the front and rear wheel individually via the tonewheels. Oil pressure sensors detect whether you’re braking. These data are fed into the electronic ABS and a smart algorithm detects whether the front wheel is still gripping or whether it’s locked out and therefore sliding. The system does this continuously at an incredible high sampling rate, within milliseconds. When you pull the brake lever, you pressurise the system, which pushes out the brake pistons. The ABS has its own oil reservoir, which is connected to the hydraulics of the front brake via super-fast solenoid valves. The rear brake is used to collect data, but it doesn’t get controlled by the ABS. If the algorithm detects that the front wheel is locked, it drains oil into its own reservoir, reducing the braking pressure just enough to let the front wheel carry on rolling. This process occurs several times per second.
The ABS can be adjusted to suit different use cases via the Bosch eBike Flow app or via the KIOX-300 display. In off mode, the ABS is off, working like conventional brakes. The ABS Touring mode is best suited for urban environments. ABS Allroad is designed for moderately off-road terrain, allowing the ABS to intervene quite heavily when braking. This is particularly suitable for bikes with less aggressive tires, which tend to slide out quite easily on gravel, for example. The ABS Trail mode was developed in collaboration with athletes and intervenes a lot later in the braking process. As a result, the brakes should remain as powerful as possible, keeping the braking distances short. For this, the Bosch system will accept a bit of sliding and allow the rear wheel to lift slightly. The ABS Cargo mode is designed specifically for fully loaded cargo bikes with a small front wheel, in which case the rear wheel is unlikely to lift. Not every mode will be available on every eMTB as each brand can decide which modes suit which eMTB and install them accordingly. The KIOX 300 display represents the modes graphically via small landscape pictograms.
Field test of the 2023 Bosch eBike ABS
One thing is clear: ABS cannot change the laws of physics when braking. The maximum braking grip still depends on your tires and the terrain, and the brakes themselves determine the braking feel. The ABS only activates at speeds above 6 km/h. When braking from a higher speed, the system intervenes until you stop or until you release the brakes. All in all, we were absolutely impressed by the performance of the new Bosch ABS and are convinced that it can make ebiking and eMTBing much safer.
If you hit the brakes hard in Allroad mode, the braking distance is noticeably longer on gravel. On grippy asphalt, the stopping distance only increases to a limited extent. Experienced riders who can keep a cool head in stressful situations will be capable of achieving a shorter stopping distance without the ABS. However, the system offers other advantages: you won’t be able to get the rear wheel to lift even when you shift your weight forward and the front wheel doesn’t slide out, always remaining in control while you’re braking. While your attention might waver during a ride and you can make mistakes when braking – to err is human, after all – the ABS doesn’t take any breaks and thus always provides an added level of safety. That is if you familiarise yourself with the system and get used to the new braking behaviour. Although the electronically controlled brake offers intuitive and predictable braking, you’ve got to overcome your hesitance to pull the front brake as hard as you can in demanding situations. So, if you’re new to the ABS, we recommend that you practise a couple of hard braking manoeuvres on different surfaces to build your confidence in the system and develop a feel for the braking distance. Once you’ve done this, you can adapt your riding position accordingly, ultimately resulting in even better and safer braking. Many riders put their weight too far back for fear of going over the handlebar, which significantly reduces the braking traction of the front wheel. If – thanks to ABS – you have no or less fear of taking a tumble, you can practise keeping your centre of gravity more balanced on the bike. On very slippery surfaces with long stopping distances, one can feel how the brake lever moves closer to the handlebar because of the pressure reduction of the ABS. However, the compensating reservoir of the ABS is designed to fill up before the brake lever reaches the end of its path. That way, you’re always guaranteed to have some braking power left. You could theoretically still lock out the front wheel when reaching this point, but we never managed to so even when going from 40 to 0 km/h on a slippery surface. As soon as you let off the brake, the ABS reservoir gets emptied immediately.
In Trail mode, the ABS intervenes much later and is intended to enable more aggressive riding and braking, which proved to be the case during our tests. This mode is designed for use on bikes with wide and grippy tires. The stopping distances remain very short when slamming on the brakes. We were particularly impressed with how much the front wheel can still be controlled on gravel roads, remaining steerable without feeling nervous – that wouldn’t be the case without ABS. Even in extreme situations such as on wet roots or when landing with the brakes engaged, the front wheel doesn’t lock out. This provides a very high level of safety. By shifting your weight and riding actively, you will still be able to do a nose manual to swing the rear wheel around a tight switchback. Doing so takes some practice, however, since getting your weight so far forward on a bike without the Bosch ABS would send you flying over the handlebar. Remember to take a quick peek at the LED remote beforehand to see if the indicator light is off and the ABS is active.
Regardless of the mode you’re in, the ABS detects changing surface conditions at superhuman speed. If you start braking on asphalt and go over to gravel or vice versa, the system adjusts the brake pressure immediately, either allowing more braking force when going over to asphalt or immediately reducing the pressure when transitioning to loose gravel. The developers at Bosch couldn’t resist including a small gamification feature in this system either: after each braking manoeuvre, you can check your braking duration and stopping distance on the KIOX 300 display. However, we wouldn’t recommend putting yourself and others in danger by competing for the longest stopping distance.
If you brake, you (don’t) lose… control of your eMTB! Our assessment of the 2023 Bosch eBike ABS
The new ABS system is a big step in the right direction, though it isn’t perfect – at least not for trail riders: long wheelies result in a system error, and it must be restarted. If you lift the rear wheel and spin the cranks, like you would do to shift gears while stationary, for example, you can also cause a system error, again requiring a reboot. When riding down a steep section very slowly, i.e. below 6 km/h, you may also be caught off guard by the brakes’ uncontrolled stopping power. This isn’t just relevant for experts but also for beginners who tend to approach obstacles slower. Moreover, seasoned trail riders wouldn’t voluntarily mount the long multi-finger brake levers on their bike. But the more pressing question that many will be asking is: does the ABS teach you the wrong braking technique? At the end of the 1970s, automobile manufacturers had to overcome this same reluctance amongst motorists. In the meantime, you’ll be hard-pushed to find a car without an ABS. The fact is that the new Bosch ABS definitely requires a different braking technique, whether better or worse. At the same time, however, it provides other advantages such as encouraging beginners to assume a more balanced riding position while braking, making them less fearful and instilling them with confidence, which makes the use of an ABS very worthwhile on many eMTBs.
The availability of the 2023 Bosch eBike ABS
For the time being, the 2023 Bosch eBike ABS isn’t available as an after-market solution. It will be available on the first models from autumn this year, just in time for the deteriorating conditions of the season. The system will also be exclusive to Bosch Smart System equipped bikes. Since it’s only sold B2B, there’s no price list available. We will keep you up to date on upcoming models featuring the innovative braking system.
Our conclusion on the 2023 Bosch eBike ABS
Wow – the German company are taking ebike and eMTB safety to a new level with the 2023 Bosch eBike ABS system. Not just for trekking and touring, but also for cargo bikes and trail riders in certain cases. That said, it doesn’t just offer improved safety but also encourages a better riding position and thus your performance on the trail! The relatively inconspicuous integration is good, too, though the limited brake lever options need to be expanded by a modern one-finger variant in order to make the new system attractive to ambitious trail riders.
- active riding manoeuvres possible despite/with the ABS
- good integration
- improved feeling of safety builds confidence
- no one-finger levers available for trail use
For more information, visiti bosch-ebike.com
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Words: Rudolf Fischer Photos: Robin Schmitt