[Keith Seymore]

Not trying to be argumentative, but perhaps add some more food for thought:

In some cases the dot represents "radial force variation" of the tire.

You could think of the tire sidewall like an old wagon wheel, with "spokes" - but where the spokes have varying degrees of strength, or springy-ness.

The tire is checked and marked where the sidewall is stiffest, and then mounted to the rim oriented with the valve stem. The rim is offset some increment so that as the tire rolls the spindle stays at the same elevation, rather than the stiffness transmitting the disturbance into the spindle and then the vehicle.

We called this having the tire "vectored". When I was in vehicle development I used to have a library of "vectored" tire/wheel assemblies, to install on problem vehicles to aid in diagnosis, or to install on management/executive vehicles when we were fluffing them for demonstration rides*.

The old Uniroyal Tiger Paws were terrible. I would buy aftermarket Michelins in various sizes, which were perfect right out of the box.

So - not a balance issue per se, but still a once per rev of tire rotation disturbance. Naturally, both the tire and the wheel manufacturer have to be on board before going down this path for a particular vehicle platform.

K

*In fact - I used to have a standardized check list of tasks to perform to fluff vehicles:
1) Fix vent window wind noise
2) Vector tire/wheel assemblies
3) Fix rear axle noise
4) Balance driveline as a system
5) Etc

I knew I would have to perform these task before I even saw the intended vehicle.