Bosch update Performance CX eMTB motor

In the middle of the year, Bosch released the latest generation of the Performance CX eMTB motor. One of the most obvious differences is weight and size, and this has a huge impact on bike design. The previous Bosch Performance CX motors did leave bike designers struggling to create the geometry that some riders wanted from their eMTBs. Chainstays would end up quite long, which was awesome for stability at speed and seated climbing – but not so good for agility on tighter trails and where riders were taking their bikes.

The weight saving is significant, The Bosch Performance CX Gen4 is a full 1.3kg lighter than the Gen3 while also being about half the size. There’s a direct benefit here beyond the bike design benefits noted above – as a bike can now have a larger battery for more ride time, and still be lighter than a bike designed around the Gen3 system. Many of the bikes with the new Gen4 motor will have a 625Wh battery, a big increase from the 400Wh or 500Wh of previous models.

In terms of appearances, sure it looks smaller and you’ll notice the design of a bike using the Gen4 motor is more akin to those using other smaller motors like the Shimano system. The latest Bosch Performance CX motor also uses a regular chain ring. This helps bike designers who now have a normal chainline to design around, but it also makes for a driveline that is less plagued by mud build up compare to the tiny chain rings that the previous Gen3 motor used. The Bosch head unit options remain the same, so in terms of your tactile experience when moving from a bike with a Gen3 motor to one with a Gen4, it’s really similar. Kind of like staying with the same brand phone, as you know the operating system. What has changed is how that motor works and delivers support, and how it reacts out on the trails.

The support level when using the eMTB mode ranges from 120-340%, higher than the 300% of the previous Performance CX motor. The eMTB mode is essentially as it was before, it reacts to your pedalling input to give you the support you need, using upto 75Nm of torque. But how it does it has been updated. The response is much gentler when easing through technical terrain, but with the greater amount of support at the top end it really responds when you stomp on the pedals to clear a climb or feature on the trails. So all up bikes with the latest Bosch Performance CX motor should be lighter, have a longer battery life, and use geometry that is likely to make for a more playful bike with handling much closer to a regular trail or enduro bike. The new Trek Rail is a perfect example of all of those attributes, and more bikes with the Gen4 motor are landing on our shores right now, so why not see if there’s a test event coming to your trails? Check with one of your local Bosch dealers.