Braking/driving force control system

A method that is performed by a control device that controls a powertrain including an engine and a stepped transmission, the method comprising:

• calculating, in a current gear stage of the stepped transmission and a gear stage downshifted from the current gear stage, a first fuel cut braking/driving force corresponding to the current gear stage and a second fuel cut braking/driving force corresponding to the gear stage downshifted from the current gear stage, that are braking/driving forces that the powertrain generates while fuel cut of the engine is performed, and
• setting a set gear stage of the stepped transmission and performing the fuel cut of the engine in the set gear stage based on a relationship of a required braking/driving force, the first fuel cut braking/driving force, and the second fuel cut braking/driving force.

A non-transitory storage medium storing instructions that are executable by one or more processors and that cause the one or more processors to perform functions comprising:

• calculating, in a current gear stage of a stepped transmission and a gear stage downshifted from the current gear stage, a first fuel cut braking/driving force corresponding to the current gear stage and a second fuel cut braking/driving force corresponding to the gear stage downshifted from the current gear stage, that are braking/driving forces that a powertrain generates while fuel cut of an engine is performed, and
• setting a set gear stage of the stepped transmission and performing the fuel cut of the engine in the set gear stage based on a relationship of a required braking/driving force, the first fuel cut braking/driving force, and the second fuel cut braking/driving force.