you might try having higher torque at lower rpms and/or some trick with the tire mass.
i checked the source code and it’s kind of a design issue that wheel speed is strictly tied to ground speed and changing that code can be dangerous, it requires a good model to behave better and a lot of testing to make sure everything works fine. i added this to my long term todo list but do not depend on me, i may not be able to find a better solution.