The wire wheels on my 1935 Chrysler are constantly going out of balance. I have them balanced at the tire shop, and if I just park it for a couple of days, the wheels are out of balance the next time I drive it. The tire shop can’t figure what’s going on and the vibration if driving me crazy. I know if anyone can solve this problem you can.
My best guess is that you have wheel ants that are causing the balance problem. These little critters congregate in hidden areas of your wheels and cause the problem you’re experiencing. It’s tough to get rid of them using a garden hose alone. The real solution is to get an automotive-grade insecticide and sprayer from your local auto parts store and follow the directions exactly. Apply the insecticide and then rinse off with a hose. That should do the trick.