Alaric GT

Any ideas what could cause a side to side shimmy at around 15mph? Feels like its coming from the rear. I had the tires checked and balanced.

08'MustangDude

That can be so many things, but start basic, bad tire; a belt broke in the tire.
Balanced or not, I have had it happen... Put your spare tire on, one location at a
time, see if it stops. If you went all the way around the car with the spare, and
it did not stop the shimmy, then it's not a tire. Doubt two tires would have blown
belts. Potholes are the #1 case of tire damage.. OR, bending rims...

Then you move on to suspension; bushings...

Then check the axle bearings, one side may be going.

Check for axle play...

Derf00

Did this just start? Have you hit any curbs or potholes?

Or has this been ongoing and you're just now getting around to looking into it?

dawson1112

Side to side motion is almost always a bad tire or rim, but it is possible that you have a bent hub also.

casual man mann

Did you run over something?