DAS (Double Axis Steering) is a system developed by the Mercedes Formula One (F1) team to control the angle of the wheels to minimize drag resistance for maximum straight-line speed and control tire scrub along the track surface for better grip at the corners of the race track.
The Mercedes DAS (Double Axis Steering) System
On Valentine's Day 2020, Mercedes unveiled their all-new Mercedes W11 for the upcoming 2020 Formula 1 season. But everyone's focus is on their mysterious innovation, the Double Steering System, or 'DAS' for short, which they have brought to the pre-season testing.
How does DAS work?
So what exactly is DAS? DAS stands for Dual Steering System, the device is essentially a toe changing device. Toe refers to whether the tires point inwards or outwards front to back. It allows the driver to adjust the alignment of the front wheels from the cockpit by pushing or pulling the steering wheel. By pushing and pulling the steering wheel, it allows the driver to move the alignment of the wheels from toe-in to toe-out.
TOED-IN
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If the tires are toed in, this means the wheels are pitched in towards each other, this can assist and increase stability under acceleration, as the tires steer into each other and resist turning.
NO TOE
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If the tires have no toe and are pointed straight, there is less drag from the tires and the car will go faster on the straights.
TOED-OUT
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Whenever the tires are toed out, this means the wheels are pitched against each other, this allows the car to be more responsive in turns, but can be more sensitive otherwise.
Why is DAS used?
Although Mercedes has been very coy about what exactly is the system for, if the mechanisms in the system work as expected, it is to allow the driver to move the alignment of the wheels from toe-in to toe-out to increase the performance of the car in straights as well as corners.
Also, it is used to manage tire temperature. The mechanism works when the driver pulls or pushes on the steering wheel on the straights which activates the system and brings the angle of the wheels inwards then returning it to its original toe-out setting for corners.
What this does is that the pulling motion likely pulls the inboard side of the steering arms backward or inwards, which pulls on the front of the tires, adjusting the toe. This allows the tires to be heated more evenly across their width as they run fully upright, but the benefits of toe-out can still be deployed into the corner.
It will be of particular benefit on circuits with long straights as it still allows the inner edge of the tire to be heated as it normally will only be able to heat up on the corners of a circuit.
Photo: Mercedes AMG F1 Steering Wheel
Source: www.motorsport.com
Photo By: Giorgio Piola
Video of Lewis Hamilton using the DAS system during FP1 of the Hungarian Grand Prix 2020. When Hamilton pulls the steering wheel closer to his body, the wheels move into a straight position, but pushing back in returns them to their traditional toe-out position.
Source: YouTube/cokeFIN3
Advantages of DAS
The system has given Mercedes an advantage against their rivals as the system:
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Is available at all times for them to use compared to DRS
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It removes unnecessary downforce and drags so that the car can go faster
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Less slip angle of the tires through the corners so that less scrub and speed will be lost
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Able to go through corners faster without slowing the car down
(https://www.roadandtrack.com/motorsports/a31076350/mercedess-dual-axis-steering-advantages-explained/)
To read more about DRS: https://torqueguru.com/blogs/news/what-is-drs-in-formula-1
Is DAS Legal in F1?
In short, DAS is legal in F1 for 2020 and illegal in 2021. According to the FIA technical regulations,
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10.2.1 With the steering wheel fixed, the position of each wheel centre and the orientation of its rotation axis must be completely and uniquely defined by a function of its principally vertical suspension travel.
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10.4.1 Any steering system which permits the re-alignment of more than two wheels is not permitted.
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10.4.2 Power assisted steering systems may not be electronically controlled or electrically powered. No such system may carry out any function other than reduce the physical effort required to steer the car.
The DAS system passes all the following regulations that have been set by the FIA.
- On regulation 10.2.1; the steering wheel is fixed so no changes have been made to the vertical suspension travel.
- On regulation 10.4.1; only two of its wheel have the ability to be re-aligned and not more.
- About regulation 10.4.2; the dual-axis system is mechanically connected via the steering shaft and it is not electronically controlled nor is it electrically powered.
Source: https://www.fia.com/regulation/category/110
But this still doesn’t stop their competitors from lodging a protest against the use of the system.
- ESPN reports that Red Bull has launched an official protest against Mercedes over the use of the DAS system. Red Bull Team Principal Christian Horner said: “First of all, it is a very clever system, and so all credit to the ingenuity behind it. I think the fundamental question for us is, does it comply with the regulations?”
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Racefans.net reports that Ferrari team principal Mattia Binotto says it wouldn't be able to introduce a DAS system until mid-season. "I have no idea if it would be worthwhile or not, Binotto said, but it's certainly longer than that."
Mercedes have been working closely with the FIA to ensure the legality of the system and that it is within the regulations. The FIA has also pointed out that it is okay with the system being used as it complies with this year's regulations.
The FIA also pointed out that although the innovation is deemed “unconventional”, it is still part of the steering system and not the suspension. As such, the system could not be in breach of any regulations pertaining to suspension. (https://www.racetechmag.com/2020/07/mercedes-das-system-ruled-legal/)
Overall, the FIA is happy with the use of DAS by Mercedes, and the legality of the system can only be proven by the race stewards if there is a protest. (https://www.motorsport.com/f1/news/fia-mercedes-das-system-is-legal/4689414/)
However, with the 2021 regulations set to prohibit the use of this system, under a set of a new regulation that does not exist in the current regulations. The rules for 2021 state the requirement of a "fixed distance":
"The re-alignment of the steered wheels, as defined by the position of the inboard attachment of the relevant suspensions members that remain a fixed distance from each other, must be uniquely defined by a monotonic function of the rotational position of a single steering wheel." (autoblog.com)
Therefore, 2020 might be the only time we will get to see the Dual Axis Steering system in action.