Why the McLaren Artura and Ferrari SF90 Stradale Have No Reverse Gear

The McLaren Artura is the first McLaren to use a V6 engine and the first electrified model from the Woking marque to enter series production - excluding the limited-run P1 and Speedtail. As such, it ushers in a new chapter for McLaren.

The Ferrari SF90 Stradale is no less significant in terms of internal milestones. At Maranello, it is ‘only’ the most powerful road-going Ferrari ever, as well as the company’s first unrestricted series-production model, unlike the LaFerrari.

Both are plug-in hybrids and share an interesting detail: neither car has a conventional reverse gear within its eight-speed dual-clutch gearbox.

Weight-saving in plug-in hybrids

Why remove the reverse gear, then? Put simply, omitting it in this type of hybrid avoids duplication of components and delivers a modest weight saving.

As you will know, plug-in hybrids are considerably heavier than equivalent cars powered solely by combustion engines. That is because they add one or more electric motors and, above all, the batteries required to power them. Any measure that helps keep that mass under control is therefore welcome.

Extra weight is already an issue in an ordinary car, increasing inertia and undermining handling. In performance-focused supercars such as the McLaren Artura and Ferrari SF90 Stradale, however, every additional kilogram becomes especially important.

Despite its 7.4 kWh battery and electric motor, the British model has a kerb weight of less than 1,500 kg: it weighs 1,498 kg (DIN). The SF90 Stradale’s hybrid system, meanwhile, adds 270 kg, taking its total mass to 1,570 kg dry - meaning that at least 100 kg must be added for all the fluids needed for operation.

Giving up a reverse gear was one small measure used to lessen the weight impact of the electrical hardware. For McLaren, it was the solution that allowed an extra transmission ratio without adding weight. Ferrari, on the other hand, saved a total of 3 kg compared with the conventional dual-clutch transmission it already used.

How the McLaren Artura and Ferrari SF90 Stradale reverse

By now, you may be asking yourself: “OK, they do not have a reverse gear, but they can still reverse. How do they do it?” The answer lies precisely in their plug-in hybrid systems, as both have an electric motor powerful enough to perform that task.

As in electric cars - which generally have no gearbox, only a single-speed reduction gear - an electric motor can reverse its polarity and turn in the opposite direction. This enables the Artura and SF90 Stradale to move backwards.

The Artura’s electric motor

In the Artura, the 95 hp electric motor positioned between the gearbox and crankshaft not only performs the duties of the ‘reverse gear’, assists the combustion engine and drives the car in fully electric mode, but can also smooth gear changes.