Lift and down force


Vehicle aerodynamics can also change the weight of the moving vehicle
  
Downforce pushes wheels more tightly to the ground.  That is desirable.

Spoilers increases downforce.
​  

Downforce

Downforce is a good thing for cars. Is it desireable for a Gravity car or a CO -2 Draghster??

Lift increases with speed.



Lift

While not a good characteristic in car design, lift will reduce the friction tires create on the ground. This would be desirable for a Gravity car or a CO- 2 dragster...