Baffling me and the local wheel balancing community. Any thoughts most welcome and much appreciated.

I20 (63 plate) developed a wheel wobble around 50mph. Had the front wheels balanced and problem solved. Around 100 miles later, wobble returns. The wobble can be felt through the car. Ive never driven it (my wifes) but as a passenger its worrying. Cant imagine what its like to drive !

Have repeated the above process 4 or 5 times and changed wheels front to back at the last balance, but still 100-150 miles later the wobble returns.

The second time we did a balance, the operative put on weights that went about a 1/4 to 1/3 around the inside of the rim. Never seen so many. Id guess 15 to 20 weights.

The next balancer was at a different garage and the top man/owner. He was equally surprised by the number of weights. He removed them, balanced the wheels (with far fewer weights) and as usual, all was well for a few days.

Any ideas as to a logical explanation for this illogical occurrence ? Taking the car in next week, so any thoughts I can pass onto the garage might help solve the mystery.

Many thanks in anticipation..