wheel hoppin' Why ?

This would be my guess also. A freind had a late model with custom wheels and tried everything. Then found out the aftermarket wheels had a different hub size. He put adapters on and problem solved.
My T Bucket had a front tire that bounced like a basket ball. Turned out it was the fix-a-flat I used when I was out on the road. Had the tire dismounted, cleaned out and rebalanced. Won't use that **** again!