One of the most common problems people experience with used cars is shaking wheels at high speeds. This is a huge headache that many repair shops take FULL advantage of because it can be caused by a number of problems, and only the mechanic will be able to tell what it is. For this reason, the mechanic will tell you anything, or a number of things but shaking wheels are ALWAYS caused by one single issue, or a combination of two issues; depending on the milage on your car.