Drift Condition

A “drift” is a condition of a car, where, when pushed beyond the tire’s limit of adhesion, it exhibits lateral slip.  Or put, a car that has gone sideways.  There are many instances where this might happen, and generally speaking, all of these conditions describe a drifting condition.  Speeds required to induce such a condition need not be high.  Some of us have experienced speeding into a turn on a rainy day and felt the car slide slightly sideways.  The loss of traction can be either front tires, rear tires, or both. 

An “understeer” is described as a loss of traction at the front wheels, while “oversteer” is characterised by a loss of traction at the rear tires.  A “four-wheel drift” is a condition of both of the above.   In racing, all forms of drift are used consistently to adjust a car’s behaviour, but generally speaking, excessive drift is undesirable when competing against the clock.  But to many, recovering from an excessive drift is a thrill and is a skill that is useful in all fields of racing.  In short, it’s the ability to recover control of a car that has been pushed too far.  

The understeer drift is usually the most common drift.  This is because most production cars as well as race cars exhibit this behavior when the steering input is greater than the front tire’s ability to hold onto the road.  It is common because most of us have encountered a situation where we try to avoid a collision with an unanticipated obstruction in the road.  We turn the steering wheel suddenly, and the front loses grip.  Then we notice the car hasn’t turned in that direction very well so we cut the steering some more,  still to no response.  What happened?  Well, a tire has to be rolling in order to turn in the steered direction, thus front tires locked up with the brakes will only move toward the vector (direction) of the car’s momentum… In this case, nearly straight.  Second, the tires can only turn with enough force provided by the front tire’s grip, and beyond that steering more will not help the car turn as the front tires slide in the vector of travel.   However, production cars are usually set up with a strong tendency to do so.  Why?  Well this condition is very easy to correct…by slowing down and more drivers can recover from an understeer.  Many race drivers prefer a mild understeer setup also so small mistakes won’t affect overall outcome of the race.

This brings us to the following form of drift…an oversteer.   It is a rear tire’s loss of traction.  It’s called oversteer because the car turns more than the steering input due to the rears sliding outwards…pointing the car toward the inside of the turn.  To recover from this condition, one must “counter-steer,” or turn the steering in the opposite direction, precisely and maintain control of the attitude.  Too much correction will cause a sudden oversteer the opposite direction and not enough will slide your car out of desired path.  

the following description is on the oversteer and understeer condition: