Dodge Durango Forum II Archive

Robert Bivins
rbivins@hotmail.com

In that article are links to the various studies done on what ABS can an cannot do.

BTW, the box anology, while valid, is not entirely relevant when it comes to vulcanized rubber (the type of rubber in car tires).  In almost all braking conditions (except very slippery conditions, like ICE), the particles of rubber in the tire create a wedge at the point of skid (more like trying to slide a box on carpet, which any moving company will tell you gets progressivly more difficult with distance).  Also, most road surfaces (even water, because of it's surface tension) also wedge at the point of skid and create an even larger wedge (asphalt, cement, gravel, dirt, water, snow, all contribute to this "wedging" effect).  Look at a skid mark.  It gets darker as the vehicle approaches a stop -- the friction is increasing as the distance, the wedge, and the temperature increase.

Plus, with car tires, their friction increases exponentially with the generation of heat (why Nascar driver swerve at the start of a race, and one of the reasons for the burn-outs that preceede drag races).  The hottest you can make a tire is by skidding it.  (provided you don't exceede the molecular bonding tempurature of the rubber itself -- which is higher for vulcanized rubber).

One more point, you may notice that radial tires aren't even round.  Radial tires always exhibit that preceeding wedge even before and exteem situation arrives.  Which is why all passenger cars now come on radial tires.  Bias-ply tires did not exhibit this behavior.
--Robert's $.02