Massive caster variance Side to side
This must be a way to check alignment that you’re not familiar with. If you refuse to watch the video, you won’t understand.
This gauge attaches to the hub.
Here are the instructions.
If this type of tool is foreign to you, I understand. Young guys in construction used to bring in new style tools that I didn’t think I’d like. Sometimes I was wrong and the new thing was better than the old way.