Bosch has announced the CX Performance Line Race Motor, a lighter, more supportive eBike motor that offers up to 400% assistance. It does not replace the current Performance Line CX Motor; rather, it is a limited edition drive unit that will be distributed among twenty leading eMTB manufacturers to sell with their most race-focused eBikes. At the Tweedlove Festival in Scotland we got a very quick spin on one of those; a 2023 Trek Rail, but it was enough to notice some tangible performance-related benefits.
“It is like taming a bit of a wild horse at times, but it’s just learning its characteristics, learning how to ride it, pre-empting some of it, making sure you’re in a good body position, making sure you’re riding aggressively, and then it’s awesome. If you’re a bit, sort of, resting on your laurels, out for a cruise, it can definitely take you for a ride” -MTB Legend, Tracy Moseley.
Bosch Performance Line CX Race Limited Edition Motor
The Bosch Performance Line CX Race Motor offers direct support of up to 400% of the rider’s power in its exclusive Race Mode. That compares to the maximum of 340% offered by the Performance Line CX motor in Turbo Mode. They don’t look vastly different from one another, save for the color of the magnesium casing and the fact that it has Performance Line CX Race written across the non-drive side. Indeed, the two motors share the exact same bolt pattern, making it easy for manufacturers to add a top-level race-focused eBike model to their existing line-ups.
That doesn’t mean you can upgrade your current Bosch-equipped eBike, however. While you could theoretically switch out a Performance Line CX Motor for the new CX Race Motor (the batteries and hardware are all cross-compatible, the motor itself won’t be available as an aftermarket upgrade; it is OEM only.
Hopes dashed, let’s take a closer look at the Bosch CX Race Motor that could be on your next eMTB.
The Race Motor isn’t any more powerful; it still offers a maximum torque of 85 Nm, and still cuts off at the regulation-stipulated 25 km/h. In Race Mode, the 400% assist simply gets you up to speed faster, i.e. it accelerates harder.
Joris Ryf, Swiss eMTB Pro said, “The most important thing for me was a drive unit that would get me up to top speed faster and keep me at top speed for longer – and we succeeded.”
An early version of it was tested at the EWS-E in 2021 under MTB Legend, Tracy Moseley. In fact, it was actually a Performance Line CX motor that had received some tweaks, with a special Race Mode that was tailored to her specific needs.
However, it’s not just some new firmware on the Bosch CX Race Motor; it’s actually a bit lighter, too. Bosch aren’t too specific here, but the materials used for some of the internals parts are lighter, allowing them to shave 150g off the motor’s weight, bringing it down to a claimed 2.75 kg, making it the lightest drive unit in the entire Bosch portfolio (still a bit heavier than the 2.6 kg Shimano EP8).
What modes are available in addition to Race Mode?
That will be up to the eBike manufacturer to decide. On the 2023 Trek Rail we rode, the modes offered were as follows:
- Race
- Turbo
- eMTB
- Tour+
- OFF
What’s Tour+? A Bosch spokesperson tells us that the Tour+ Mode on the CX Race Motor offers a range equivalent to Eco through to the 400% assist Race Mode, a bigger range than that offered by the regular Tour Mode on the Performance Line CX Motor that operates over a shorter range equivalent to Tour to Turbo. The nomenclature is a bit confusing to be fair, and actual numbers would be easier to understand, but in the absence of that information, here’s a quick overview of how each mode behaves from Bosch.
How does the CX Race Motor ride?
Having wrecked myself on the trails that morning, I was up to little more than a spin around the park. Honestly, I didn’t think I was going to be able to notice any tangible differences in how the motor performs. How wrong I was.
Of course, the step change from Turbo Mode into Race Mode was appreciable, the acceleration offered by the Race Mode satisfyingly faster than that offered by Turbo. While that’s cool, it was something else about how the motor behaves that, at first, shocked and appalled me, and then put a big smile on my face as I started to realize the implications for technical climbing.
When I stopped pedaling, the motor carried on delivering power to the rear wheel. That is the case on the Performance Line CX Motor, too, but that “Extended Boost” feature in the exclusive Race Mode is somewhat enhanced. It felt like the motor was still dishing out Watts up to a full second after I had stopped pedaling. When I asked Bosch about this, they made it clear that the distance traveled is the limiting factor here.
The Extended Boost will give you an additional 2 meters of distance traveled after you’ve stopped pedaling. So, the time that the Extended Boost operates over depends very much on how fast you are going. I was tinkering about at speeds close to stopped, both along the flat and on a very steep banking, so the Extended Boost felt almost throttle-like. Tracy Moseley used the words “lunge” and “surge”. I could just tease the pedals through a quarter of a pedal stroke, and be consequently sent.
The benefits that will offer to certain technical climbing scenarios are obvious. Consider yourself faced with a steep, rocky, technical climb not dissimilar to what the EWS-E racers at Finale Ligure will be faced with today. It’s the kind of climb wherein completing a full revolution of the pedals runs the risk of smacking one of those pedals into a rock, resulting in, at best a stall and a quick dab, and at worst, a complete departure fro your bike.
With the Extended Boost offered in Race Mode, riders could conceivably be teasing the bike up such gnarly technical climbs, without ever having to risk a complete pedal stroke. Of course, that could actually be a disadvantage when faced with a sniper root-ridden slippery slope, at which point I imagine one would drop down into one of the lower assistance modes to prevent the rear wheel spinning out.
The other tangible difference in ride feel offered by the Bosch CX Race Motor was the abrupt cut-off in power that occurs at the 25 kph assist limit. Whereas the Bosch CX Performance Line motor curtails its assistance as it approaches the 25 kph limit, the CX Race Motor delivers full assistance right up to the limit. It’s definitely more of a shock to the system, feeling a bit like you’ve started dragging the brakes, but it does mean the motor will help riders go faster for longer.
Will the Bosch CX Race Motor be at EWS-E Finale Ligure?
It sure will! We can confirm that MTB Legend, Tracy Moseley, will be on the latest Trek Rail sporting the production CX Race Motor for the very first time. Given that the EWS and DH World Cup Seasons are now over, Tracy’s Trek Factory Racing Team members, Jamie Edmondson and Hattie Harnden, are on the start list, too; they could also be on a Trek Rail powered by the Bosch CX Race Motor.
Now for some speculation… Given today’s announcement of the Bosch CX Race Motor, we wouldn’t be all that surprised to see this final race of the EWS-E Season offer a glimpse of some new eBikes. Lapierre, Orbea and Scott all have enduro eBikes that are frequently raced at the EWS-E, so keep an eye on what bikes are underneath Adrien Dailly, Antoine Rogge and Kevin Marry (Lapierre), Edgar Carballo Gonzalez and Florencia Espineira Herreros (Orbea) and Remi Absalon (Scott).
