Stromer installed the Schlumpf Speed Drive in 2016/2017 in the ST1 T (brown) and ST1 S (green) models, also known as the green frog, and limited itself to these models. They differed minimally in terms of equipment. The ST1 S had no luggage rack and slightly narrower tires.

The on-board electrics were based on 36 V, the motor controller was integrated in the 500 W hub motor and the bike was controlled via a display on the handlebars (as with the ST1 V1 / V1.1), i.e. without an omni.
In combination with a Shimano XT 9-speed cassette, the two models offer a total of 18 gears.