My 380 drove silky smooth until i put 20s on it, it has a strange vibration now and shakes above 110. They have been balanced recently and have got like 10 weights on each rim and even a couple of weights on other areas of the rim. I have budget tyres on them ( brand is CARBON 245/35/20, wondering if cheap tyres would have an effect (tyre shop says no), if they r just not balanced properly or what?????Is it normal to have so many weights and r 20s usually hard to balance??? I have those plastic locator rings where the rim slips on also. Any advice would be appreciated thanks.

Could be the tyres.

I had a set of Maxxis MA-Z1s previously, and one pair had a pretty bad vibration through them. Needless to say, they were kept on the rear of my car lol Have you rotated your tyres front-to-back at all? Or tried to get a rotation elsewhere? Could just be a dodgy/lazy store.

Regardless of vibration, cheap tyres like Carbon are a no-no...

were they new rims? could be a aq flat spot of buckle in one. its not hard to do with 20's. (very little protection from hard impack like pothole etc)

First thing I would try is a balance. Is the vibration coming through the steering wheel.? If they where balanced properly there shouldn't be weights everywhere on the wheels. Should only be in one spot.

First thing I would try is a balance. Is the vibration coming through the steering wheel.? If they where balanced properly there shouldn't be weights everywhere on the wheels. Should only be in one spot.

when weights are everywhere its usually because they have tried to balance a bent rim or shitty tyre, chances are they did it as well as they could, mind you it wouldn't hurt getting a second shop to give them a go.... some shops have no idea what they are doing..