Question on my truck!?

So i recently had my truck worked on and i have notice when I drive it, it shakes in the back..not bad but it is noticeable..now i have a really old spare tire on the drivers side rear wheel..is the shaking related to the wheel or is it something else?? plz help!

?2016-01-15T08:10:08Z

it could be either wheel balance, bearing issues, shock absorbers, tyre pressures or tracking or even the wheel not secured properly - have a tyre centre look at it.

-The Majestic Sloth-2016-01-15T08:16:45Z

Thanks Francis..very helpful, the problem seems to be the wheel balance..THANK YOU!