How the Mercedes DAS system works

The Mercedes team made all the headlines and gossips during the first week of testing with the DAS system. During the testing, they showed a totally new system where the driver can pull and push the steering wheel to control the front tires. But what does this Mercedes DAS system really do?

DAS Systems

During the testing Mercedes announced they created a Dual Axis Steering system, also called DAS. This system can change the steering angle for the wheels, but also the toe angle between the wheels. So now we know what it means, what does it do?

Toe

To know what the DAS system does we first need to know what we mean with the toe. Surely you know we have 5 toe’s on our feet, but that is not the toe’s we are referring to here.

Toe is a part of the suspension setup that the team adjusts for every race. When we try to describe this simple: The toe describes the angle of the wheels relative to the straight line on the track. So when a car drives with 0 degrees toe the wheels will be straight with the head of the car. When we have a car with a positive toe the wheels will point inwards and with a negative toe, the wheels will point outwards.

In a race situation, the teams could use a system with a negative toe, or a positive toe. This wouldn’t be very big angles, but there can be benefits found with something between a 3 degrees positive toe and a 3 degrees negative toe.

Effects

But what are the effects that make toe so important? When you have 0 degrees toe you will minimize tire wear on the straights, but most of the tracks have corners also (Unless you are doing a drag race). So 0 degrees toe while give you the best straight-line speed.

But when you go in a corner you will notice that the inside tire doesn’t need as much track as the outside tire. So if you change your front wheel toe in a negative degree both your wheels will point outwards. This is ideal for taking lots of corners, but you will lose speed on the straight. This would mean that a negative toe would be ideal in a circuit with many corners

Using a positive toe with the wheels pointing inwards you will have a much more stable car on the straights, and it would be much harder to control the cars into the corners. A positive toe would mean the car gets much more easy to handle on the straight.

How other teams use it

Normally the teams would setup the toe of the wheels for a race. So the teams would pick the best trade-off between tire wear and benefits on a track to track basis. The teams would take the cornering speed, straight-line speeds, suspensions settings in the account and pick a toe setting that would be the best for them. So the teams will need to make a trade-off between either straight-line speed or cornering speed.

Mercedes DAS system

But Mercedes is now able to use the Dual Axis Steering to change the toe angle while driving. The Mercedes drivers can pull or push the steering wheel to create a negative or positive toe setting. This will help the team greatly with reducing the tire wear, increasing the straight-line speed and increasing the cornering speed.

Secondly, the Mercedes team could use the system to balance the temperature in the tires. They could use the DAS system to pull the tires outwards while driving behind a safety car or during an out-lap to create more drag on the tires and thus getting more temperature in them. Something both Mercedes drivers complained about a lot.

Temporary System

The Dual-Axis Steering will be a temporary system for Mercedes. The current regulations would say is it’s legal to use it. While there is currently some discussion that it could break the Parc-Ferme rules, the system is currently legal. But in the 2021 rules, this system has been banned as the steering wheel can only be moved to left or right.