Balancing AFTER alignment.

Cass

This is a pretty basic question but best to check.

Got four new tyres, Kumho 235/40/18s, and then had the four wheel alignment/tracking done. Within a few days I noticed a slight "whomping" noise and vibration from the rear of the car which gets worse with speed. It subtle at under 40mph, worse at 60mph and at motorway speeds its bad. Now I won't exaggerate it won't deafen you and even the heater turned on drowns out the nosie. So whatever the issue its subtle, but annoying.

Symptoms are "whomping" noise from the rear, slight "stepping out" of the rear on rough road/ground while going striaght, virbration in the steering wheel, and a sublte drift to the left when I let go of the steering (not counting road camber as it happens within 100 yards of letting the steering wheel go).

I took of the rear wheels as its definitely coming from the back. Found no issues with brakes, discs, hub, bearing, etc.The control arm bushes are worn and to be replaced shortly enough but this issue was not present at all before the alignment. Usually I wouldn't ask and just replace the arms considering them to be the problem, but this did not happen before the new tyres went on. There was a month or so between the four tyres fitted and the alignment. It only appeared directly after the alignment. When I contacted the garage they said the wheels may need balanced again.

Here is the basic question.

I had the wheels/tyres balanced when the tyres were fitted. Would they have gone "out of balance" during the alignment? Its possible a weight got knocked off but I assumed that once the new tyres were fitted and the wheels balanced that alignment could not create an out of balance effect after the fact. I've had this done with my other car (tyres, balancing, alignment) and never suffered any sort of balancing issue that needed done again after the alignment.