A top speed run may or may not have preceeded this issue as I was getting to know my car and its performance over a long drive... in Mexico. The top speed seems to be limited to 127mph (GPS indicated) -- can anyone verify this?

Back in Blighty, a vibration began to arise at motorway speeds. At first, I thought that it might be a flat tyre, or the road surface, or the fact that the tank was very close to empty.

However, the air suspension operates correctly in all three ride heights and the engine revs freely when stationary from idle.

The issue is evident over 20mph and when over 55mph, the vibration is prominent. 70mph ellicits a proper judder.

Additionally, at 54mph cruise control (the balance between comfort and making progress on the motorway), the juddering increases when under load i.e. knocking down a gear to tackle an incline.

My thoughts are that it is drivetrain related and another forum have ventured three opinions:

- sticky calliper

- propshaft centre bearing

- transfer box

What is likely to be the cause, from the syptoms described, in your experience? Happy to elaborate further., as required.

Also, is this an issue most likely created or excacerbated by high speeds? --------
2006 Buckingham Blue/Parchment White AJV8 Vogue

Torque converter if you had said under light load but disappears when. Raising, so luckily that puts that out.
I’ve read ‘propshaft centre bearing’on previous threads, so I would look carefully at that. 2012 Orkney Grey Westminster 4.4TDV8 with Ivory interior.........nice!
Alfa Romeo Giulietta
Just one Montesa now, 349 White Wonder
Austin A40 Farina MK2
1975 Morris Marina 1.8TC
1973 Honda CB250 K4

I'm surprised at the lack of commentary on this thread -- neverthless, the issue has now been resolved and for the benefit of closure, the issue was identified as an out-of-round tyre. Replacing with the spare has resolved the issue and I'll now swap all five tyres for new all seasons. --------
2006 Buckingham Blue/Parchment White AJV8 Vogue

Glad it's sorted. I was about to suggest a check on tge rims which are prone to buckle . I once had a buckled wheel which had been balanced perfectly . It was discovered when a tyre place filmed the wheel being spun . ----------------
2010 RR tdv8 3.6 ( gone but not forgotten ...)
2012 RR tdv8 4.4
2004 RR 4.4 V8 (M62) -gone but not forgotten (sob)
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