Mercedes most innovative of gadgets was raced for 17 grands prix but will not feature next year after regulation changes deem the Dual Axis Steering system illegal.
Developed over a number of years, DAS was the talk of the paddock in pre-season testing when, on day two in Barcelona, cameras first picked up Lewis Hamilton moving his steering wheel not only rotationally, but also in a linear fashion.
The system was seen to increase the toe angle of the front wheels with debate raging on two fronts. Firstly, was the system legal and, secondly, what advantage did it provide?
To the first point, yes, it was legal. Red Bull protested DAS on the basis of Article 3.8 and Article 10.2.3 in the technical regulations which state “no adjustment may be made to any suspension system while the car is in motion”.
Mercedes maintained the device did not adjust the suspension settings and the stewards agreed, noting in the official decision document: “As a general conclusion, it is very simple to conclude DAS would be illegal IF it were not part of the steering system,” read the stewards’ document. “So the main challenge and debate has to be on whether it can be considered to be part of the steering system. The stewards decide that DAS is a part of the steering system.
"Therefore the Stewards consider DAS to be a legitimate part of the steering system and hence to satisfy the relevant regulations regarding suspension or aerodynamic influence."
However, ahead of the delayed start to the season, the FIA confirmed the system would be confined to that of a 'one-season wonder', with regulations for 2021 stating explicitly that a steering wheel must travel only on a single rotational axis.
Article 10.4.2, again in the technical regulations, states: “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.
“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.”
With the lengthy development and short shelf life of DAS, no other team shipped an equivalent device to the circuit this year.
But what benefits did the system provide?
One of the benefits of running an increased toe angle is that the amount of scrubbing - rubber running in an opposed direction to the direction of travel of the car - increases friction and therefore produces heat.
This can be useful in a number of scenarios. Most commonly, this will be a benefit in qualifying. Getting tyre temperatures spot on ahead of launching into a qualifying run is critical for a driver to get the most out of the car.
With DAS, Mercedes could micro-manage the tyres on the out-lap with considerably more ease than the rest who would need to weave more or ride the brakes to increase surface and core tyre temperatures.
Similar scenarios to this also include safety car restarts, of which there were several this year, and the race start itself.
DAS also has, in F1 terms, a dramatic effect on the aerodynamics of the car, positioning the tyres in a more aerodynamic angle on straights while also allowing the car to turn better in tight corners when deployed at the other extreme.
Where DAS really shone, however, was in the wet.
For all of the reasons above relating to tyre temperature, DAS could just about be the greatest wet weather assist of them all.
A constant problem in the wet is retaining tyre heat and, tick, DAS makes this easier. But the party piece comes when a track is drying and slick tyres are maybe two or three laps away from being the preferable option.
With DAS, Mercedes had the option, if needed, to change compound early and have fewer concerns about heat retention. Running DAS on full for laps at a time may not have been an option given the increased tyre-wear it promotes - all systems have a weakness - but if used correctly it gave Mercedes an ace in the hole.
It is sad to see a development with so much potential go to waste after just one year but in Formula 1, you know there is always another gadget lurking around the corner.
Where there's a regulation, there's a loophole and it will always be found by someone.
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