Focus ST Handling Secrets Revealed: How Ford Engineers Made a Front-Driver Drift
The Ford Focus ST is an amazing handling machine, being incredibly unique amongst front drivers for its ability to rotate the rear end. More than just chassis tuning, however, the Focus ST has a secret.
Well known for using what the company calls Torque Vectoring Control on the front axle, pitch the ST into a corner and its rear-end swings around by another means.
We recently tested the Focus ST on the track for an upcoming comparison article with the Mazdaspeed3 and AutoGuide hot shoe David Pratte had his suspicions, which have since been confirmed by Ford’s chassis guru at Team RS Vehicle Dynamics (and a man with a rather similar name) David Put.
“I will not tell all the goodies,” says Put about Ford’s handling secrets, “but you’re absolutely right.”
What Put is referring to is the sensation we experienced; that the Focus ST rotates its rear-end by braking the inside rear wheel in a corner.
When the ST debuted Ford boasted about its Torque Vectoring Control system that can add brakes to the inside front wheel. Rather than a heavy or complex limited slip differential that distributes more power to the outside wheel and less power to the inside wheel to help maximize vehicle grip (and, therefore, speed), TVC simply reduces the amount of power making it to the inside wheel by adding brake.
That happens too says Put, commenting that the car’s computer knows to brake the inside front wheel to help the vehicle rotate. In fact, the front does 95 percent of the work, he says, though that extra five percent braking in the rear is Ford’s secret sauce.
This trick helps create oversteer (a trait commonly associated with rear-wheel drive cars), while also reducing understeer – a performance robbing trait of front-wheel drive cars.