Tire hop

Sounds like an unusual way to describe a broken belt. The best symptom to look for is the steering wheel oscillates left and right as you slowly drive through a parking lot, if it's caused by a front tire. If the belt is really bad, that corner of the car will rise and fall too with each wheel revolution. Broken belts on rear tires are felt as if the seat is swaying left and right, or the back of the car is rising and falling slightly.

Some broken belts are easy to identify. The vehicle has to have the suspect tire raised off the ground. If you want to pursue this yourself, here's links to some articles with valuable information:

https://www.2carpros.com/articles/jack-up-and-lift-your-car-safely

https://www.2carpros.com/articles/how-car-tires-work

Rear tires can be spun by hand. On front-wheel-drive cars, we use the engine to spin the tires, but that is safest when both front tires are off the ground. One wheel will spin on its own. Check that tire first. To make the other one spin, use the brakes to stop the spinning wheel, then block that one with something like scraps of lumber. It won't require much force, but doing that will force the other tire to spin. I don't like to accelerate the engine because if you aren't careful, the blocked tire can try to spin and can spit the lumber out.

These first three photos show three types of badly broken belts. I added my drawing to show a fourth example that is very elusive and hard to identify. This occurs when a belt separates slowly over a long period of time. The blue arrow is pointing to a spot in the lower left tire where this hump developed, but when this occurs slowly, the tread has time to wear down making the tire appear to be okay. What the specialists will look for is the area in the lower right drawing with the red arrow. The tread surface looks good, but its the groove where the raised area shows up. This is a weak spot in the carcass. As with other broken belts, you'll see this in the steering wheel at low speeds, but it will also cause an out-of-balance sensation at higher speeds. Balancing the wheel / tire assembly will not solve the thumping. The weak spot is less able to support the weight of the car, so that corner drops a little each time that area touches the road surface.

Alignment specialists also "read" the tire wear patterns, and that can involve running their hands over the tread. We have to be very careful when doing that as broken belts often have the wires from steel belts sticking out. Those are very sharp and really hurt when you run into them.