vauxhall 1.9 cdti diesel ?

It can sometimes be very difficult to trace vibrations,as you are on the move I would be looking at a rotational imbalance and you have done the wheel balance,I remember having one like this,all wheels balanced numerous times and a constant vibration at 50 mph,swapped the wheels across the axle and all was well,you just have to try different things,check all suspension and steering joints,discs and pads etc,not sure on yours but if there is a support bearing on your o/s shaft then check that also,maybe g/box and engine mounts may be worth having a look at also,good luck

cdc
March 2015