[cjsplat]

The front and rear wheels have different angles of attack on the vector of the car, so they have slightly different friction vectors.

The result can be oversteer (when the back slide more) or understeer (back slides less).

And it can change depending on road conditions, tire inflation, velocity, acceleration/deceleration. And of course changes radically from vehicle to vehicle.

Covered in depth in the movie Cars "You need to turn left to turn right". :-)

Of course the same thing applies to two wheeled vehicles also - see trail braking.