How do you keep wheel covers from flying off!

[Jim S]

In the last 50 years I have owned several Studebakers.  Besides leaking, they have one thing in common. The wheel covers won't stay on the wheels.  Today my Avanti threw a cover on the freeway and I watched it get squashed by a truck behind me.  I have modern 6" wheels to accomadate radial tires. I even bent out the tabs on the covers to keep them good and snug on the wheels.  But the flexing of the front wheels and tires seems to still push them off.  Has anyone found a good way to keep them from coming off?