Drifting and Power Slides
Power slides and drifting are synonymous. Both involve over-steer, or the vehicles rear wheels being somewhere other than behind the front wheels, such as in the above picture. With rear wheel drive vehicles, it is easy for this to happen when cornering if too much throttle is used. A driver can spin the rear wheels when in a tight corner, and quickly cause an uncontrolled over-steer.
Why Is This Seen in Rally?
While it is true that on surfaces like tarmac the static coefficient of friction is larger, and therefore sliding is slower, when driving on loose surfaces such as dirt or snow, the widely accepted method of driving in WRC is to drift around corners. This may be because the sides of the tires are able to dig into the ground.
Handbrake Turns
Another situation when drivers want their tires to break
traction is when there is a corner that is too sharper than
their vehicles turning radius. Obviously, a three point turn
is a tremendous waste of time, so drivers pull the
handbrake, to cause a loss of traction on the rear wheels
and turn the car around quickly.