As stated in the headline, my car is bouncy when driving at speeds around 40mph or over (not sure when it tapers, I drive almost exclusively within city limits). I had new tires installed less than a week ago and this issue was not present with the old set. What gives? I brought it back to them, they mentioned maybe it was the struts, after realigning it. Could the new set prompt an issue with the struts? It’s odd to me that if they’ve been weak this whole time there were no prior indicators before the new tires.
I would put money on the fact the tires are out of balance. As long as the shop did the balancing in the first place, take it back to them and tell them to check their work. Something is wrong there and they should be the ones to fix it on their dime. If there was no issue before with the struts/shocks, there should be no problem with them after the tire change.