The Trek Domane+ has only a 20T single chainring up front. This seems incredibly small and maybe great for steep climbs, but seems like it would be result in spinning out on many flat or descent situations. But a salesman was telling me this isn’t so because the motor senses your effort and regulates the torque (or something like that). Is there any truth to this? Does this mean I have to have the motor on and waste battery to avoid spinning out on flats or descents?