Bosch Updates Performance Line CX Motor – More Range, Better Performance, Less Weight
Sep 30, 2024
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Gains include greater range, more motor performance control, better walk assist and new features including hill hold and hill start assist.
Some products set the standard by which their category is judged. The Gibson Les Paul comes to mind. So does the Bosch Performance Line CX. When it was released in 2015—nearly ten years ago—the Performance Line CX was the first system dedicated to eMTBs. Since then, it has become the go-to mid-drive motor for electric mountain bikes, the motor against which all others are judged. It’s hard to believe that nine years have passed since Bosch introduced the Performance Line CX, considering how quickly the e-bike market moves.
When Bosch set out to redesign the Performance Line CX motor, they chose to keep the basic performance parameters the same: The motor still produces a maximum of 600W and up to 85Nm of torque, making for a 340 percent assist. The question, of course, is why Bosch didn’t increase the amount of assistance. In Bosch’s view, the Performance Line CX already provided the perfect balance of power, rideability, efficiency relative to battery range and drivetrain durability. More power would mean greater weight, making the eMTB heavier and less nimble; it would also result in a decrease in range because of more weight and drawing more power for the motor, as well as more wear and tear on drivetrain components.
So what changes? Well the first notable difference is that the new motor is 100g (3.5 oz.). The new motor also provides greater thermal stability; traditionally as a motor heats up, power production is reduced by the controller to prevent the motor from overheating. While the previous Performance Line CX offered greater thermal stability than its competitors, the new motor shows even more consistent performance on long rides.
Bosch redesigned the different sensors to make it even more responsive to rider input. It features new torque and cadence sensors, as well as the addition of inertial sensors. The inertial sensors measure acceleration in three axes as well as rotation in three axes—six sensors total and what this does is provide the controller a sense of where the eMTB is in space—how it is moving. The motor can now respond in subtle ways based on whether the rider is climbing, descending, riding on smooth ground or rolling through a rock garden or over roots.
Bosch has cut the amount of noise the motor produces, particularly the higher frequency sounds that tend to be the most noticeable part of the sound a motor generates.
The Performance Line CX now offers a smart walk assist; with the press of a button, the rider receives just enough power to walk up grades too steep to ride, but thanks to the inertial sensors, it tailors the speed of the walk assist based on the grade and how smooth or bumpy the ground is. They’ve also added a hill hold feature, which will provide just enough power to keep the eMTB in position for 10 seconds after releasing the walk assist button. Additionally, they’ve added hill start assistance for when the trail is so steep that it is hard to generate enough speed and balance so that you can move the foot that’s on the ground to the pedal. Hill start assist provides an extra burst of power so that the rider can get up to a balancing speed and land their foot on the pedal.
Extended boost features new software that reads how quickly or slowly the rider is pedaling and that informs how long the boost is—the slower each pedal stroke, the longer the boost.
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Flow smartphone app
Bosch’s Flow smartphone app allows riders to adjust four important motor performance variables. Both maximum speed and maximum torque can be adjusted. Assistance, which is the ratio between your effort and the motor output, can be shifted depending on the rider’s needs. Finally, dynamics defines how reactive the motor is, both how quickly the motor responds and how forcefully it responds. Move all four sliders to the right and you get maximum power and maximum reactivity—which will ask more of the battery and reduce range. Move all the sliders to the left and the motor’s response will be smoother, gentler, less noticeable, and ultimately will extend battery range.
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Purion 400 display
Bosch’s new Purion 400 display is a high-resolution color display that mounts on the bar just right of the stem and behind the bar, giving it a relatively well protected position. It is compatible with both Bosch’s LED Remote and its Mini Remote.
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Bigger batteries
As part of this new release Bosch is introducing two new PowerTube batteries, the PowerTube 800 and the PowerTube 600, 800Wh and 600Wh batteries, respectively. Rather than purchase cells from an OE manufacturer they say they designed all new cells, new electronics and new aluminum housings for the batteries. The PowerTube 800 is Bosch’s most energy-dense battery ever. It weighs 3.9kg (8.6 lbs.). By comparison, the PowerTube 750 weighed 4.4 kg (9.7 lbs.), which means the PowerTube 800 weighs 500g (1.1 lbs.) less while offering an additional 50Wh of range. In terms of energy density, that a 20 percent improvement.
The PowerTube 800 and PowerTube 600 share the same length and interface, making them interchangeable within eMTBs. The advantage here is that for the rider who wants a lighter eMTB and is willing to give up some power and range, they can swap the PowerTube 600 for the PowerTube 800. This also gives product managers the opportunity to choose the 600 over the 800 if they want to reduce the retail price of the eMTB. Riders can still add the PowerMore 250 range-extending battery.
The PowerTube 800 and 600 both use recycled materials, making them more sustainable products than previous PowerTube batteries.
The PowerTube 800 is reported to charge 2.5 times faster than other batteries, thanks to a new charging standard that the industry is adopting, called Charge2Bike.
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eShift
Another core feature of the new Performance Line CX is eShift. In addition to existing electronic shifting solutions like the Eviolo Continuously Variable Transmission (CVT), Bosch eShift will now support automatic electronic shifting with Shimano Di2 and Cues systems as well as TRP’s electronic derailleur.
ABS Pro
Bosch’s ABS Pro adds anti-lock braking to its suite of performance upgrades. It prevents front wheel lockup under hard braking, allowing a rider to brake later and harder. It also reduces the trail damage that happens when a tire skids.
With new sensors, the brake now reacts more quickly and precisely. With ABS Pro, the point isn’t to control the entirety of braking, but simply preventing overbraking in the initial moment when the brake is applied.
ABS Pro offers two different operation modes, Trail Pro and Race. The big difference between the two is that Race mode will not control for rear wheel lift—that is, braking so hard the rear wheel lifts off the ground, while Trail Pro will control for wheel lift, though to a limited degree.
ABS Pro works with two different brake systems, TRP’s DH-R and Magura’s MT7.
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Electric Bike Report’s take
If you’re wondering why a new motor didn’t include greater power or torque when most products grow in power as they get updated, Bosch resisted the urge to increase power due to the need to provide a product line that meets the requirements for Class 1 e-bikes. Many trail systems only allow Class 1 eMTBs.
This isn’t to say that the new Performance Line CX system isn’t a major upgrade. Increased range, reduced noise, greater performance adjustability and increased functionality in the form of walk assist, hill hold and hill start assistance will bring even more terrain within a rider’s comfort zone. Adding in features such as ABS and eShift will offer riders better performance with less effort on their part. Bosch sees both eShift and ABS Pro as game changers for the rental market, giving casual riders a better riding experience and making riding technical terrain less intimidating.
Bosch’s 20 percent increase in energy density with the PowerTube 800 is one of the most exciting aspects of this product launch. Riders can combine the PowerTube 800 with the PowerMore 250 for a total capacity of 1050Wh. Talk about all-day riding. The cows will come home before you will.
The quieter motor will be welcome. Mountain bikers are accustomed to hearing all the normal sounds of tires on the trail and drivetrain shifting noise, but the sound of an e-bike’s motor can be a distraction and reducing the high-frequency sounds the motor produces will make riding an e-bike equipped with the Performance Line CX a more natural-seeming experience.
The new, smarter walk mode, plus the hill hold and hill start assist will give riders greater access to less sanitized trails in the backcountry, just the sort of riding that an 800Wh battery can offer access to.
We suspect that the addition of inertial sensors will prove to be one of the more significant advances with the new Performance Line CX motor. The combination of the information from the inertial sensors informing the motor of the eMTB’s orientation combined with Bosch’s eMTB assist mode that adjusts the assist level based on how the rider is pedaling will make the eMTB mode even more dynamic and better tailoring its response to the rider’s needs.
It may be that many of these developments and improvements will appeal most to experienced eMTB riders who have experience in the very circumstances these improvements are meant to address. That’s not to say that these advancements are esoteric; a rider doesn’t need to understand all the inner workings of Bosch’s Smart System to enjoy its benefits. That said, don’t be surprised if we see a number of used eMTBs hit the market as riders move to upgrade to the new Performance Line CX.
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