S60 D5 vibration at speed
 

Hi Guys,
I have a very annoying vibration coming through my steering wheel over 55/60MPH.
The passenger seat vibrates back and forth and you can feel a vibration through the floor.
Any idea what this could be.
I took the car to kwik fit and had both front wheels balanced but this has made no difference. The tyres budget, could it be the tyres even though they have been balaced?
Cheers

I had similar, turned out to be an out-of-round rear tyre. Take it to a decent tyre place, they should be able to tell .

You should have had the rear wheels balanced too , that's usually the cause of vibration through the floor and seat . It's transferring up the steering column too . You might like to examine the tread for uneven wear and bulges , if it has just started vibrating on it's own , have you hit any pot holes ?

As above, floor vibrations come mostly from the rear wheels which are 'attached' to the car's body. Steering would be the front ones.

Maybe the shop didn't do a good job?

Mind you, wishbones can also cause vibrations.

More uncommonly, my inner carrier bearing on the left axle has play and causes intermittend vibration in the steering, pedal and sometimes floor depending on the angle the side road makes.

If the wheel lungs are very unevenly tighten (from corrosion at the lugs seat on the wheel) it can deform the brake discs and cause vibrations