Defo Wheel balance.
weird tho as ive always felt wheel balance from 70++
Have you checked both the outside AND inside rims for damage?
Rim damage could be a factor.
The idea that you can "feel" wheel balance at any speed seems odd to me.
The whole point of having the wheels balanced is so that all vibration/judder/steering deviation is removed isn't it?
You might also want to consider a full geometry check.
Most tyre places can do it.
Regards Guy.