Wheel Slip

So as we covered in our blog, Wheel Slip is "The ratiothat's applied to the tire by either the car's engine or
of the rotational speed of a braked wheel to that ofbrakes. This can either decelerate or accelerate your
an equivalent free-rolling wheel, expressed as avehicle.
percentage. The slip is equal to the speed of a braked-- Laterally: this type of force is generated when your
wheel divided by the speed of an unbraked wheel,vehicle drives around a curve. It makes a car change
expressed as a percentage".. according to What thisdirection & eventually, the tires issue lateral force when
basically means is that the speed of the free-rollingcombined with the ground.
wheel & the braked wheel is pretty much a ratio thatIf you have Traction Control, then you shouldn't have
is shown as a percentage. The formula is as shown:to worry about this at all. Traction Control was
Slip % = Speed of the braked wheeldesigned to reduce Wheel Slip & keep a good amount
Speed of the unbraked wheelof traction at the wheels that are driven when the
Do you get it? I hope so. I have to admit, it was a littleroad is covered in either water or snow. This specific
difficult in words, but when I actually drew out theTraction Control System reduces Wheel Slip by
formula, it was a lot easier to understand; right?braking the actual wheel that is losing traction. This
There are actually two types of contact that your tirestechnique was designed to work at speeds that are
can make with the road that you just so happen to bebelow 35 MPH.. or 56 KM/H.
driving on: Static Contact & Dynamic Contact.The control module monitors in the Traction Control
-- Static Contact is when the tire & the road are notoversees the wheel speed very closely. If in the time
slipping proportional to each other. The coefficient ofof acceleration the control module perceives Front
friction for static contact is usually higher than theWheel Slip & the brakes aren't applied, then the control
coefficient for dynamic contact; which means thatmodule will automatically enter something called
static contact provides a better traction percentage"Traction Control Mode". When Wheel Slip is finally
for your vehicle.detected, Traction Control works in this order:
-- Dynamic Contact occurs when your tire is slipping in1. It closes the Isolation Valves that are normally open.
correspondence to the road. The coefficient of friction2. The Start pump/motor & supply volume/pressure
for this type of contact is lower; therefore, you havecircuits to the hydraulics in the front.
less traction.. which may not be so good when you're3. Open & close build & decay valves work so that
driving in the rain; right?they can maintain a minimum percentage of Wheel Slip
To be quite honest, Wheel Slip can only occur when& keep maximum traction.
the force applied to a tire is greater than the tractionIf it were up to me & my car, I'd want to have Traction
that is available to that specific tire. The force can beControl installed on my vehicle to save my car & my
applied in one of two ways: Longitudinally or Laterally.Factory Original 2009 Volkswagen Routan Wheels..
-- Longitudinally: this force comes from the torque