My wife has a 2002 Hyundai Elantra that has a rotational noise coming from the left rear wheel. We just got it back from the shop where they replaced the left front wheel bearing and rear brakes/rotors, and the right/rear wheel bearing was replaced about a year ago. It's a thumping noise that speeds up proportionally to the speed of the car. Normally I'd expect a bad tire or warped rotor, but the tires are relatively new and we didn't notice the problem before we took it to the shop last week (though it's possible we weren't hearing it over the wheel bearing noise they fixed). Is it possible we got a bad rotor, or the shop did something wrong? Or could this be something new entirely (which would be entirely typical for this car). All help appreciated!