Tech insight: What does Mercedes' steering wheel mode do?

This system appears to be an extension of the pushrod-on-upright (POU) solution that we've seen teams employ since 2017 and has become a fixture on almost every car on the grid.

POU solutions have become favourable as they offer an offset to the behaviour of the suspension as the driver steers, meaning that the car's ride-height can be effectively adjusted.

The idea is that the car is lowered toward the track at a point when downforce is most required (cornering) and lifted back to its normal position when the car is steered straight.

This allows teams to effectively grab some free downforce in the corners and lose it as the car straightens to reduce drag.

However, this can come with some pretty big drawbacks for the driver, as it creates a dead zone at a crucial point where he'd usually need feedback.

On top of this, the steering will no longer naturally center, meaning the driver is always steering the car, to the point where it feels like they're actually pulling on the wheel to straighten or steer the car.

Mercedes AMG F1 steering wheel

Photo by: Giorgio Piola

This new system being tested by Mercedes appears to resolve some of the inherent issues caused by running a larger POU offset, largely mitigating the driver feel issues and allowing the overall POU concept to be pushed further for aerodynamic gain.

A dramatic change in toe angle, as witnessed when the system is in use, not only comes in handy when we consider the 'POU' implications but also the car's behaviour both on tyre life and the potential to offer a straightline speed boost.

As the wheels are toe'd out in the corners it will help with turn-in. Then as the driver draws the steering wheel away, he will go from a neutral position to toe-in, which will reduce tyre scrub and improve straightline stability. The reverse can be expected when entering the braking and cornering phase.

Clearly there will be anguish amongst the rest of the teams about what Mercedes has done, as they will be left with two clear avenues. Either find a way to replicate the steering mode themselves, which could take months, or get the system banned by the FIA.

Mercedes pushrod-on-upright solution from 2019

Red Bull RB15 pushrod-on-upright solution

Where it all started… Ferrari ran a version of the POU solution back in 2017 but their drivers didn’t like the feel it gave at certain critical moments in the steering phase

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