Talkin trucks here, get your minds out of the gutter

I have noticed when driving around on my citys terrible streets that 9 out of 10, 2004-08 F150s boxes (beds) bounce & shake around alot (okay not ALOT but more than the rest of the truck or other trucks), after it caught my eye I looked for it on other trucks & noticed they are basically the only ones that do, they must have corrected something on the 09+ trucks because they seem to be solid. Anyone else notice this? PS my 05 does it too I can notice it in the sideview mirror, whats up with this?

 

I've noticed my being wobbly as well... I just don't care, because it hasn't fallen off yet.

Plus I figure it being the materials.

Personally, I wouldn't worry about it.

 

All trucks do this, it is a matter of an open top structure without bracing. The older trucks did not have a stiff enough of frame to accentuate the problem. But if you were to check the gaps between the tailgate and bed most have spots where the paint has been rubbed off. The newer F-150s do show a very taught movement over a bump. A Tundra looks like it has hinges in the middle.