High Speed vibration, can't find what's causing it.

It may not look pretty but you may need to balance both sides of the wheels. On my 72' Dodge van I insisted on the weights be put only on the inside also. Had a top-in vibration and had to allow weights on the outside also to rid it. 295/50/15 TA's

I’ve had everything from an 8 inch wheel to a 14 inch wheel on my drag cars and never had to use a weight on the front side of the wheel. And I’ve had weight on some that you guys probably wouldn’t run. I glue my slicks on so it’s not as easy as just unmounting the slick and trying it in another spot.