The Les Schwab stores I've used don't really balance 19.5s, they just put that "Equal" garbage in them. What I ended up having to do with the last set of 19.5s from Schwab (on an Isuzu truck) was take it to a real truck tire shop and have them balance them for real.
Les Schwab tried to tell me 19.5s don't get spin balanced with weights, the "Equal"' additive is the only way to do it. But they couldn't explain why my wheels had balancing weights before they got their hands on them, and why they still shook after their so-called balancing job with that stuff they put in them.
