I have a 2010 Toyota Corolla, and I’ve been experiencing some pretty harsh shaking/vibration for the last 4-5 months. The tires make a soft thumping noise similar to a flat tire, and I was told that my tires are cupping on the inside, and that it’s likely that my struts are giving out. My car has 114,000 miles on it. The vibration is in the steering wheel, seat, and floor board, and gets worse along with the thumping noise when going at highway speeds. Two tires are 6 months old, the other 2 are 2 weeks old. I don’t hear any creaking or rattling, only thumping from the tires and the normal sound of the engine when I drive. The tires have all been rotated and balanced within the last week, and the alignment is perfect. Does anyone know what might be causing this, or if it really is the struts?