Short shifting is a driving technique in which the

gear A gear is a rotating circular machine part having cut teeth or, in the case of a cogwheel or gearwheel, inserted teeth (called ''cogs''), which mesh with another (compatible) toothed part to transmit (convert) torque and speed. The basic p ...

is changed up before reaching maximum engine RPM or, more precisely, the acceleration optimized RPM shift-point. By short shifting, the

engine An engine or motor is a machine designed to convert one or more forms of energy into mechanical energy. Available energy sources include potential energy (e.g. energy of the Earth's gravitational field as exploited in hydroelectric power ...

does not reach its

power band The power band of an internal combustion engine or electric motor is the range of operating speeds under which the engine or motor is able to output the most power, that is, the maximum energy per unit of time. This usually means that maximum ...

, and therefore maximum vehicle acceleration is not attained for the gear from which the short shift was performed. In racing, short-shifting is a technique intended to avoid losing valuable acceleration time changing gears later. Although this means not being able to accelerate using the engine's peak power at the moment of the gear change, total acceleration overtime may be greater as no acceleration can happen during the gear change. This can aid

overtaking Overtaking or passing is the act of one vehicle going past another slower moving vehicle, travelling in the same direction, on a road. The lane used for overtaking another vehicle is often a passing lane farther from the road shoulder which ...

by ensuring that the car is in the right gear in anticipation of a maneuver. The most common reason for a short-shift in day-to-day driving is to improve fuel economy. By keeping the engine at the lower end of its RPM range less fuel is consumed. This is especially common in "torquey" vehicles, vehicles whose engine torque curve peaks at lower RPM than the power curve, because the higher torque at low RPM allows for better acceleration characteristics without winding the engine up into its powerband. Many diesel truck drivers practice a specific type of short-shifting called

progressive shifting Progressive shifting is a technique for changing gears commonly practiced by drivers of semi-trailer trucks. It is meant to reduce fuel consumption — something very important for drivers who travel several hundred miles each day. Progressiv ...

, wherein the RPM shift point is increased with each gear but is still short of the power band. Another reason is to intentionally reduce power and/or torque to improve traction in sub-optimal road conditions. For example, applying full engine power to the drive-wheels on wet or icy roads may cause the wheels to slip. Likewise, short-shifting can help maintain vehicle stability through bends by avoiding an unsettling shift in balance mid-corner.

References

{{reflist Driving techniques