Audi A4 Cabrio Sport 3.0 Quattro - judder at high speed

[Poopedmummy]

Hi all

I start to feel a judder through the steering wheel and the seat at about 60mph which is really quite bad at 80pmh +. If I speak, the judder can be heard in my voice. So far I have:-

1) Had the tracking done (as advised by a friend, but I didn't know at that point about laser wheel alignment!)
2) Had 4 new tyres, all balanced (however, I had Falken Ziex's on previously all the way round and a tyre place I went to for another 2 talked me into having 2 Nexen's as that's waht they had - so I have 2 of each
3) Tyres have been rotated
3) All wheels have been laser aligned
4) an 'Audi specialist' told me he thought it was a wheel bearing (when previously when I had the brake pads checked I was told everything looked OK)
5) Got quotes for wheel bearing and booked it in with another garage, who told me they didn't think it was the wheel bearing when they test drove it and said they thought it was the tyres (although they told me where they test drove it and couldn't have driven it fast enough, I don't think)

I'm paying out all over the place but not really coming up with the answer. Not really sure what to do next? Do I order 2 Falken tyres to replace the Nexen's and see if that does the trick? Opinions/help would be very much appreciated.

I'm hoping to sell the car at some point so want to make sure all's well.

Thanks

[Poopedmummy]

Just realised my old signature from the days of my VW Eos has shown :-/

[scotty33]

An odd one but something like deposits or mud or cow whatsit inside the wheels could cause this, but guess they would have noticed?
Maybe some play in a driveshaft/propshaft, or even bent, which would put it out of balance.
Some places can balance wheels 'on the car' this also balances the disc/hub assembly, could be worth a try?
Are the tyres wearing evenly, no undue squealing when you drive on painted surface? Are they 'round' i.e no high spots when you jack up and spin them?
Is it possible the balance weights have fallen off?

[Poopedmummy]

I have been told that the rear tyres are laddering ie wearing on the inside?

[scotty33]

That would point to 'toe out' at the rear I think? One other thing, as it is a quattro, are all the tyres the same size? To some extent a pair near the end of their life matched with a new pair are effectively different sizes, though in practice, I found I could get away with that scenario on a 80q I used to run.

[Poopedmummy]

Thanks for your reply. The front two tyres are about 6 months newer than the rear but I haven't covered many miles during that time. I think I'm going to stop off at the local friendly tyre place and just get them to check the wheel nuts are all properly tightened as a next step. Just to tick another box!

[hibberd]

Maybe worth looking at the way the wheels sit on the axle..there is a lip inside the wheel that sits over a raised portion on the hub...they can get damaged and cause the wheel not to center properly on the hub. My BMW had this and when the insert inside the wheel was replaced with a new aluminium one it was back to being good.. It was like a 2-3 mm thick insert inside the center of the wheel..