To activate Boost mode, press and hold the plus button on the handlebar. Stromer ST1 X, ST2, ST2 S: Riding speed switch (Boost mode) The models Stromer ST1 X, ST2 and ST2 S built before 2018 provide full assistance at the touch of a button: The Boost mode helps you accelerate up to 20 km/h or 12 mph even without pedaling. Your ST1 X keeps you up-to-date, any time, any place: The Stromer OMNI software shows the speed, battery level, miles traveled, current location and more and lets you make individual motor settings – even over your smartphone. How This $7,000 E-Bike's GPS Tech Thwarted a Thief. Stromer ST1X Pdf User Manuals. ... the oddest praise Stromer… View online or download Stromer ST1X Operating Manual ... with Stromer's mobile app and activating the bike's GPS-locating and theft-mode capabilities. "Boost" mode will kick in propelling you along at a brisk 12.5 mph, no muscle power required. If you live in a walk-up, "Move" mode will also come in handy.