Tyres, when properly mounted, have a line around the top of the bead which should be concentric with the rim, that is sharing the same radius as the rim... not moving in and out....
A tyre which "appears" out of round when fitted, can often be so because it has not been fitted properly..... the bead not being properly seated and thus showing the non-concentric line around the rim.
It can be balanced on a machine, but runs like a dog on the road......... producing a vertical tramp if bad enough.
I am always wary of tyre dealers who claim a tyre is "out of round", as if the manufacturer would not have checked.... that said, I did see a lot of P*****i car tyres back in the early 90's which had deformed beads, resulting in the tyre appearing, "out of round".....
This was a manufacturing defect caused by poor handling of the steel hoops used in the manufacture of the bead being hung up on a rail to cool after being made, this very action caused an out of round bead wire and hence an out of round bead and so on.... QED.
Bad QA following on from a bad step in the manufacturing process......
This is one of the reasons why I fit my own tyres.....
