The back end of the Austin Seven uses quarter elliptic springs like those on the Wilkinson bike, except only one per side. Even though the Austin has a torque tube, under power the twist to the back axle would hump one spring up and flatten the other one down. This had the effect of slightly turning the back axle into the turn, hence the car would oversteer. Once you got used to it you could compensate by a series of steering wheel adjustments.