BOSCH VS BROSE: Which E-Bike Mid Drive System is Better for You?Mid drive motor systems are becoming increasingly popular in E-bikes and are going to topple in-wheel hub motors as the dominant mean of propulsion. Mid drive systems bring improved balance, better flex, easier maintenance, less wiring and some other benefits which may be related to the bike style or design. However, if you want to opt for a mid drive system you should be aware of some differences and other considerations, as not all mid drive systems are the same.
In mid-drive biking systems, major differences are defined by the supplier of the engine and the entire propulsion system. Brose and Bosch are two German firms with decades spent as leading developers of electric automotive suppliers. Recently, these two companies entered the waters of electric bike propulsion. The two firms develop parts for end manufacturers of bikes, among which are some of the well-established and leading brands of bicycles.
Bosch eBike SystemsBosch eBike offers its motor systems to both bike manufacturers and those who want to build their own custom E-bikes. All Bosch e-bike propulsion systems are divided into three categories:
• Active Line – for those who need nothing beyond basic transportation from A to B.
• Performance Line – for anyone with more adventurous lifestyles and those who have more adventurous bike endeavors or are forced to use an E-bike in difficult conditions, such as long or steep uphill.
• Performance Line CX – the most advanced system for those who often go offroad or want to climb up high mountains or have very long rides.
The Active Line of e-bike propulsion components is the most interesting for those who look for reliability of an E-bike for everyday use in urban conditions found in New York City. The motor unit has three sensors to measure pedaling power and sensation. The motor delivers 35-50 Nm torque to the crank, depending on the mode. There are four modes (by torque ascending): Eco, Tour, Sport and Turbo. The speed limit is 20mph which is in compliance with federal regulations for E-bikes.
The power is sourced from the Active Line powerpack, a 400 watt-hour, 11Wh strong battery pack which weighs 5.5-5.7 lbs. Bosch claim it is the lightest battery pack in its class. The battery has Single Cell Monitoring (SCM) and Battery Management System (BMS) protection which keeps it safe from overcharge, undervoltage and overheating.
Bosch systems include Intuvia, which is represented as a board computer – as its controller unit. Besides basic information such as the speed, distance, battery level, it has some advanced functions, such as shift recommendation and USB charger for other devices (e.g. a smartphone).
As said before, Bosch systems have four modes. Turbo is the highest level which supports highest cadences for sport riding. The next mode – Sport is meant for fast riding in urban, extraurban and offroad conditions. The Tour mode is the next and is meant for longer rides. The least powerful option – Eco - emphasizes range. The off mode also exists. When off mode is selected, there’s no assistance but all functions of the Intuvia controller unit and display are still accessible and working. These modes are available in all three classes (lines) of Bosch E-bike kits.
Bosch lists the featured e-bike manufacturers on its website. Some of the cycling powerhouses among these include Bulls, Cannondale, Scott, Trek, Felt and others.
Brose E-Bike MotorAnother German automotive electric parts supplier is Berlin-based Brose. They entered the e-bike propulsion market somewhat later than Bosch and other major manufacturers, but are trying to gain the momentum as different. The main feature of Brose propulsion systems is their inconspicuousness. The motor is constructed in a manner which makes it very small by volume yet very powerful, often even more powerful than motors of their competitors. Add to that that with many bicycle manufacturers they have developed fully frame-integrated batteries and you realize that the entire system can be concealed so effectively that many people wouldn’t even notice your bike is an electric one.
One main difference of Brose systems when compared to Bosch is its high customizability. The system itself is just a motor, while the Brose brand controller unit exists, but remains just an option. Batteries are not a part of this system. The bicycle manufacturer can choose or develop batteries on their own. One of the main reasons for this is to enable bike manufacturers to integrate the battery units into various parts of the frame, depending on the bicycle type and purpose. It also serves the marketing purpose, as some of the renowned brands may prefer to implement some of their own ideas related to E-bike construction and not be limited to what the propulsion manufacturer insists on. This fact has for a short period of time from 2015 onwards gained some major names such as Specialized, Bulls, Scott, Steppenwolf and Kettler, among others.
A good example how the customization worked out with Brose is the Specialized Turbo fully suspended MTB which besides barely visible motor and battery incorporated into the frame features no display. It has only control buttons on the downtube for setting the assistance level and toggling it on and off, as well as ten LEDs as the battery indicator. Simply, those who ride full sussers don’t care much about the distance and other metrics, they just want to enjoy in the wild. And a display is way too sensitive for going through so much dust and mud. It is simply not needed.
On the technical side, Brose offers serious power, the 90 Nm torque for the 250-watt output. It uses 36v nominal voltage. Bikes with Brose system have max speeds set within the 15 mph to 28 mph scale.
Finally, one of the features in which developers of this system gain pride is its quietness. Brose claims that its tiny belt-powered mechanism is actually the quietest in the ebike propulsion market.
ConclusionWhich of the two systems you choose depends on what you need and expect from an electric bike. If you’re riding in the city, take up long journeys on the road or just enjoy some free biking in urban environments, Bosch powered E-bikes will be an ideal fit for you. If you prefer assisted mountain biking and want a rugged, suspended (possibly full-suspension) bike, the firm construction of fully integrated Brose system will be a better option. Note that some bike manufacturers chose to cooperate with both Bosch and Brose – but usually not on the same type of bikes.