Bosch's New Firmware Doesn't Add Watts—It Changes When You Get Them
Bosch's free firmware update delivers 120 Nm and 600% assist—but only when you need it. Here's what actually matters for battery life and ride feel.
Bosch just announced a firmware update that does something unusual in the e-bike world: it doesn't add more peak watts. Instead, the Performance Upgrade 2.0 tweaks when and how the motor delivers support. For the CX and CX-R motors, you'll get up to 120 Nm of torque and 600% assist—but only in short bursts when the software detects you're struggling through a technical section. The rest of the time, the bike rides quieter and more efficiently.
Here's what that means if you're trying to squeeze a ride in before dinner: you can run a lower assist mode (Tour+ or Eco+) to stretch battery life, and the system will spike power automatically when you hit a root garden or a steep pitch. You're not holding full boost through smooth trail—just getting it when pedal input says you need it. After testing it briefly on some dirt hills at Sea Otter, the transition felt nearly invisible. The catch: this only works if you're pedaling hard. It's not a throttle. If you soft-pedal, you won't get the spike.
The update also lets you adjust Extended Boost length (that residual push after an obstacle) and adds a Drivetrain Tensioner feature in eMTB+ and Race modes. The tensioner pre-tensions the drivetrain to eliminate slack between motor and rear wheel, which should reduce that brief lag when you hammer out of a tight corner. Bosch claims it'll also reduce freewheel wear. I can't verify the longevity claim yet, but the mechanism makes sense—less lash should mean less shock load on the cassette.
Two other pieces worth noting: a new 12A fast charger (500W, charges a PowerTube 800 to 50% in an hour) arrives by end of 2026, and there's a Trick Check feature that records wheelie duration and jump distance. The charger's useful if you can plug in at work. Trick Check is mostly novelty unless you're deliberately training manuals.
The best part: it's a free over-the-air update starting May 4, 2026, for existing CX/CX-R motors (BDU38). No shop visit, no new bike required. That's rare enough to mention twice.
