Why Most Electric Cars Don’t Use Gearboxes – And When They Actually Do

The vast majority of electric cars today don’t come with a gearbox—and for good reason. While gearboxes are essential in internal combustion engine (ICE) vehicles, they’re mostly unnecessary in electric cars. In this article, we’ll explore why EVs don’t rely on gearboxes, what gearboxes do in ICE cars, and when having a gearbox in an electric vehicle can still make sense.

What is a Gearbox and What Does it Do in an ICE Car?

In ICE vehicles, the engine doesn’t produce enough torque at low RPMs to move the vehicle effectively. A gearbox solves this by acting as a torque multiplier. For example:

1st gear ratio: 3:1

Final drive ratio: 3:1

Torque multiplication: 3 x 3 = 9

Engine torque (e.g., 200 Nm) x 9 = 1800 Nm at the wheels

This multiplication is crucial for acceleration and performance. Without it, the vehicle wouldn’t move efficiently at lower speeds.

However, gearboxes come with trade-offs: they add mechanical complexity, energy losses, and reduced fuel efficiency due to friction and inefficiencies in gear changes.

Why Electric Cars Don’t Need a Gearbox

Electric motors have three native characteristics that eliminate the need for multi-speed transmissions:

1. Instant Torque from 0 RPM

EV motors produce maximum torque the moment they start rotating. This eliminates the need for torque multiplication at low speeds.

2. High RPM Capability

Electric motors can spin up to 20,000 RPM, enabling a wide speed range from a single gear ratio.

3. Electronically Limited Top Speed

Most EVs are limited to lower top speeds than ICE cars to preserve battery efficiency. With clever gearing and high RPM capability, one fixed ratio is usually enough.

Case Study: BMW i4 eDrive40

Motor torque: 430 Nm (0–5000 RPM)

Gear + final drive ratio: 11.115:1

Wheel torque: ~4780 Nm

Top speed: 190 km/h

Motor RPM at 130 km/h: ~11,300

This showcases how a single-speed drivetrain can handle everything from quick acceleration to highway cruising.

The Porsche Taycan & Audi E-Tron GT Exception

Unlike most EVs, the Porsche Taycan and Audi E-Tron GT use two-speed gearboxes on the rear motor. Why?

1. Efficiency at High Speeds

Lower RPM at high speeds reduces energy losses from back EMF and eddy currents, increasing range.

2. Higher Top Speed

A longer second gear allows the car to hit higher speeds without spinning the motor excessively.

However, designing a multi-speed gearbox for EVs is technically challenging due to the high, instant torque. These gearboxes are expensive and complex, which is why they’re currently reserved for performance EVs.

What’s Next for EV Gearboxes?

As technology advances, we may see more two-speed gearboxes in mainstream EVs, provided manufacturers can deliver affordable, durable, and efficient solutions. For now, though, the simplicity and efficiency of single-speed electric drivetrains remain the industry standard.

Final Thoughts

Electric vehicles don’t need gearboxes for the same reason they dominate traffic light drag races—instant torque and high RPM. But when higher efficiency and top speed are critical, a well-engineered gearbox still has its place—especially in high-performance models.