About the only thing that will cause the wheel to bounce on any car is the strut being bad.
Worn struts/shocks, tire out of balance, or bent wheel.
Possible worn out brakes
Vibration, no but excessive bounce or wheel hop, yes.
front wheel drive
No. They are All Wheel Drive or Front Wheel Drive
Flat spot on the wheel. Bad wheel bearing. (however its usually the front not the back) Rotate the wheels and see if the problem travels with the a certain wheel
There is a detailed description of how to do this at the following URL. It is for a Saturn SL2, but should be similar for your Saturn Vue.http://www.ehow.com/how_5014553_replace-wheel-bearings-saturn-sl.html
Could be a wheel bearing, brake pads worn,
the answer is you just don't do that. and if you did. you must of hit a horse. because otherwise. the wheel wouldn't bounce. only everyone in the world knows that.
Tire out of balance or bent wheel.
All of the Saturn's have been front wheel drive, EXCEPT for the few SUV's that have been all wheel drive. The SL2, SC2 and SW2 are all dual cam and the SL1, SC1 and SW1 were all single cam.
You need to have a wheel press. Other than that it's self explanitory.