Your questions answered

Do electric cars have gearboxes?

Do electric cars have gears? Do they drive like an automatic car? Here's everything you need to know on the subject

Drive selector

After a minute or two inside an electric car, you'll probably notice a gear selector somewhere about the cabin, similar the ones in many cars with an automatic gearbox. But, instead of using a multi-speed transmissions like you'll find in a petrol or diesel car, almost all electric cars, from the Fiat 500 up to the flagship Mercedes EQS, only have a single gear.

Why do electric cars have only one gear?

There are many reasons why electric cars have only one gear. The first is that electric motors revolve (or 'rev') significantly faster than internal-combustion engines. A typical electric motor can rev at up to 20,000rpm, far higher than the usual 4,000-6,000rpm limit for a normal road car.

Also, electric motors are power-efficient throughout that rev range. This means they don't only deliver their optimum performance within a small, narrow rev band. As a result, electric cars make maximum torque almost instantly from zero revs, so they don't have a specific rev range suited to low-speed driving or acceleration.

The reason conventional diesel and petrol cars need a gearbox with multiple gears is because these engines are only capable of generating useable torque and power within a narrow band of engine speed.

Varying gear ratios help conventional engines keep within that 'power band' at different road speeds. That’s why a petrol car will easily accelerate to 20mph in first gear, but won’t go much faster without reaching the engine’s rev limit, or 'redline'. By the same logic, you'll struggle to pull away from a set of lights in sixth gear, as this ratio is designed for cruising at faster speeds.

Electric cars can reach top speed in a single gear, with little compromise in low-speed driving or usability. What engineers do is pick a gear ratio that strikes a good balance between acceleration and top speed. Pick a ratio too low, and the engine will accelerate very fast, but may be limited to a low top speed. Conversely, if engineers pick an extremely high ratio, the gearing may be optimal for high-speed runs, but acceleration suffers.

Porsche Taycan 4S

Can electric vehicles have more than one gear?

Despite all the above, some electric cars, like the Porsche Taycan, do have a multi-speed gearbox. Some teams contesting the Formula E electric single-seater race series have run two or three-speed gearboxes in their cars in the past.

Although those cars are limited to a maximum power output of 170kW, the speed at which they reach this is crucial. Some teams, like Audi, have previously run cars with a three-speed gearbox. The addition of a gearbox helped the car reach maximum power slightly quicker. However, the team has since opted to run a high-efficiency transmission system with a single gear.

For road cars, engineering firm GKN Driveline has introduced a two-speed 'eTwisterX' electric driveline. In simple terms, the addition of a second gear allows for better acceleration and top speed than single-speed electric drive units do.

For low-speed acceleration, the electric vehicle sits in first gear, helping it launch quicker. When on the motorway, the car automatically shifts to the second gear for better high-speed driving and a higher top speed. This is the kind of setup used in the Porsche Taycan, which is a more performance-focused electric car.

Does that mean hybrid cars have an electric motor with more than one gear?

Most hybrids (plug-in or otherwise) have a standard electric motor with a single gear, as this is cheaper and less complicated to manufacture. And as explained above, single-geared units give away very little in terms of performance or efficiency, mitigating the need for a two or three-speed gearbox. The internal-combustion engine in these cars will usually put its power through a conventional automatic or CVT gearbox.

What are the benefits of having just a single gear?

From a manufacturing point of view, the biggest benefits of having just a single gear to operate the electric motor are cost and simplicity. Installing a driveline system with multiple gears immediately adds cost and complexity, which increases the car's price.

Given that electric cars tend to cost more than their diesel and petrol counterparts, it's unlikely manufacturers will want to add unnecessarily to the price. This is especially true when the single-gear setup is already optimal for most electric cars, and delivers equal or even better performance than conventional powertrains can offer.

Most Popular

UK electric-car grant reinstated until March 2023
Kia e-Niro vs Vauxhall Mokka-e
News

UK electric-car grant reinstated until March 2023

The Plug-in Car Grant (PiCG) was axed back in June 2022, but will now apply to existing orders processed before 31 March 2023
7 Oct 2022
Top 10 best plug-in hybrid SUVs 2022
DS 7 Crossback E-TENSE
Best cars

Top 10 best plug-in hybrid SUVs 2022

The finest plug-in hybrid SUVs offer low running costs, enough electric range for daily use and excellent practicality. These are the best plug-in hyb…
29 Sep 2022
Hyundai Ioniq 6 review
Hyundai Ioniq 6
In-depth reviews

Hyundai Ioniq 6 review

Hyundai’s electric streamliner impresses us with its class-leading range, rapid charging speeds and interior, though you’ll sacrifice some practicalit…
4 Oct 2022