I'm getting a vibration through the steering wheel starting right around 70mph but goes away above the upper 70s.

So far I've:

- Replaced all the front suspension components such as control arms, ball joints, bushings, anti-sway bar end links, etc.

- The tires are new and have been balanced. This started when the old tires were on the car and i had those balanced too, including the 3rd time they did them we did a road force balance. Wheels were checked at the time the new tires were mounted to make sure they are running true and they are good.

- Alignment has been done a couple of times since this started and it makes no difference

- New brake rotors (and pads)

The vibration was a bit better after replacing the rotors, so now i'm wondering if it could be something else in that area? Is there any other rotational component related to rotors that could be causing the issue?

What else would you look at?

Subframe bushings? I'm inclined to think not, since the handling is great other than the vibration. When I had a really weird suspension issue in the rear where the car was very unsettled going over bumps, and after replacing the subframe bushings tht went away. The point of mentioning that is that the bad bushings were very noticeable. The front is great other than vibration. No weirdness over bumps.

Other things i can think of: Steering rack, bushings in the steering column? CVs? Drive or prop shaft bearings or balance?

Worth checking the rear prop shaft bearing.
I had a similar vibration at 70 mph and it was a knackered bearing. All the best
Chris

Others;
1966 Jaguar 3.4 S type
1992 Jaguar Xjs 4.0 Coupe
2003 Jaguar Xjr

thanks for the info, Chris. Would the rear prop shaft bearing show itself through the steering wheel?

I found an imbalance in the propshaft on a different car and it was more of a shaking of the whole car

Generally for me, if you feel it in your seat, its the rear. If you feel it in the steering wheel, its in the front.

So, a few more questions:

- Does it do it all the time at that speed regardless of road? or do you notice it on a section of road which you typically will drive up and through 70mph ( like going onto a motorway / highway ) ?

- Do you feel vibration when you make gentle changes away from straight ahead when on gentle winding roads ? or very gentle slalom-ing it.

Other rotation parts: The front drive shafts, if there is play / imbalance in them, I supposed you could feel that through the steering. Can you feel any play in them at all? V8 or else ...