Mercedes' Dual-Axis Steering: all you need to know

Mercedes was in the spotlight after Red Bull lodged an official protest against its new Dual Axis Steering (DAS) system. Formula One stewards, however, rejected the Red Bull protest.

Although Formula One teams will be allowed to continue racing their 2020 cars next year, a clause banning DAS has been added in next year’s technical rules.

Valtteri Bottas upstaged Mercedes teammate Lewis Hamilton on Saturday to take pole position for Formula One’s season-opening Austrian Grand Prix.

Mercedes was earlier in the spotlight after Red Bull lodged an official protest against its new Dual Axis Steering (DAS) system. Formula One stewards, however, rejected the Red Bull protest.

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A note about the front tyres first...

The first thing to know/note is that the Formula One cars' front tyres are always pointing slightly outwards. When a car wheel is designed to run with its front tyres tilting slightly inwards or outwards, it is known as camber. Inwards tilting is the negative camber and outwards tilting is positive camber.

Why are they tilted? 

This is because when the car corners, its weight is transferred onto the outside wheel. With negative camber, the outside of the tyre becomes flatter to the road. It allows the tyres to maintain a better angle with the track in the corners. A rough rule: the faster a car is likely to drive around corners, the greater will be the negative camber.

What does the DAS system basically do?

Controlled by the driver by pulling and pushing on the steering column, it appears to change the alignment of the front wheels.

“We have a system in the car that introduces an extra dimension to the steering for the driver that we hope will be useful during the year,” said Mercedes' technical director James Allison. “It allows the driver an extra dimension of control on the steering system.”

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How does DAS help?

With the current car and tyres setup, the inner edge of the tyre’s tread surface is heated up more than the rest of its width on the straights. With the DAS, the tyres will get heated more evenly across their width as they will be running fully upright on the straights. And the benefits of the negative camber can still be gotten in the corner.

Is this system legal?

Rival teams have protested, some have even lodged official complaints, but the FIA twice saw no reason to ban it - once during the regular pre-season testing and again recently following Red Bull Racing's protests. 

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So all teams will soon start using their versions of DAS technology?

Not quite. Although teams will be allowed to continue racing their 2020 cars next year, a clause banning DAS has been added in next year’s technical rules. This means Mercedes will benefit from it for a maximum of only one season. And it also ensures that teams are not forced to make expensive financial commitments to develop their own systems.

“The re-alignment of the steered wheels must be uniquely defined by a monotonic function of the rotation of a single steering wheel about a single axis,” states the revised article 10.4.2.

“Furthermore, the inboard attachment points of the suspensions members connected to the steering system must remain a fixed distance from each other and can only translate in the direction normal to the car centre plane.”