Cost savings is parts of it, for example Ford almost sold 1 million trucks this past year. Multiply approx $100 x 1 million and it doesn't take an accountant to see how expensive this would be.

However the most likely reason is that all auto manufacturers design their suspensions with some level of understeer as they feel this is safest for the way the average person drives. Too little understeer, i.e. oversteer can cause the "untalented" driver to slide the rear end out in a hard turn, this is amplified with a pickup since most of the time the bed is empty. BUT, with the later designs like the Short bed Supercrews they are more "balanced" weight wise (front to rear) as compared to an empty standard cab long bed truck and therefore can take more advantage of reducing understeer (adding oversteer). The simplest way to accomplish this is with the rear sway bar and I predict a few years from now F-150s will come from the factory with rear sways bars as standard or optional equipment, at last on the Screws and possibly the Scabs.

Here is a simple quote that will help you understand the effects of oversteer/understeer a little better and also simply explains why most cars are made with excessive oversteer. For more info do a search on "Oversteer Understeer"

"Understeer is safer than oversteer. If the car understeers, and no correction is made the result is a wider corner than intended, but the car remains stable. If the car oversteers, the turn made has smaller radius than intended. The smaller radius produces higher cornering forces bring the required traction even closer to the limit of the rear wheels, and thus causing even more oversteer. The situation becomes worse until the rear wheels lose grip completely; the car spins and all directional control is lost. "


All in all it has been my experience that a properly sized/designed rear sway bar on an F-150 has made a dramatic improvement in the handling and due to better side to side stability has made it even safer in emergency maneuvers. BUT, as with most suspension changes you need to understand how these chances affect your vehicle so you can use them in the safest manner.

 

Absolutedly not!

Actually a properly designed rear sway bar could help with towing, one of the many ways is it will make your truck more stable in side winds and therefore reduce trailer "side to side sway" etc.