You might have seen the headlines from the second practice of Formula One stating how the Mercedes team have come up with a great idea to change the steering set up while actually driving the car.
This system is the DAS or Dual Axis System. It allows the driver in the car to pull and push the steering wheel to adjust the angle of the front tyres or 'Toe angle' as it is called in the automotive world.
So why is this toe angle so important in racing, I will explain it all.
Usually a team sets their car to either have an inward or outward toe angle depending on the race track. It all depends on whether its a high speed track or twisty curvy track, the engineers see where they can trade off the benefits and where they can gain the most in terms of car stability and manuvarability.
You see a car with inward toe angle will have two advantages,
the car will be more stable on high speed straights and the car wont wiggle around due to a shaky steering wheel input especially when it is running on a bumpy track.
And outward toe angle is really useful when there are a lot of corners for the track. You see with an outward toe angle when the car is turned the inner tyre turn much sharply compared to the outer one. This helps the driver in maneuvering the car because as you can see in the below picture. the inner radius is smaller for the car compared to the outer one and hence the car can turn in more smoothly and efficiently. If the car didn't have a toe angle this turning process would be more difficult cause the outer tyre is fighting or dragging against the inner one.
Image: The pink line clearly a higher radius than the yellow line.
Tyre temperatures are another factor which toe angles affect with inward angles producing more drag and heat on the inner side while outward angles heat up the outside. A driver could potentially use this to heat up the tyres more quickly than other team cars.
So now with DAS the Mercedes drivers have the chance to do this inward and outward toe angle adjustment live at any time during the race. This may only bring about a few Km/hour (miles/hour) of speed, but as you know in F1 1/1000th of a second matters usually.
It will be interesting to see which teams copy this idea from the Mercs. But whatever it may be , next season these types of mechanisms cannot be used by the teams, so enjoy it during this season.