C5 X7 noises

[steveclv]

So the C5 is such a quiet vehicle compared to what I am used to but I'm trying to find the source of a particular noise that I now hear all the time, having got used to driving the car. I hear it mostly on good surfaces, I think tyre roar blots it out on poor roads. It sounds like a medium pitch wow-wow kind of sound, fairly faint but now of course I listen for it. It seems to be speed related but is not engine or auto box (I have changed revs/gears but the sound doesn't change) but it does change if I go over a dip or hump in the road - when the car goes light over a hump at speed (40-50MPH) then the sound momentarily disappears until the car settles again.
It doesn't sound OMG serious but it is just a little annoying.

Any thoughts?
Thanks

[mickthemaverick]

I'd check for clearance between the wheels and brake back plates and ensure that a piece of inner wing plastic is not catching the tyres as a first move.

[steveclv]

I'll give it a look tomorrow as I'm replacing the fuel filter and motor mounts but it doesn't sound loud enough for plastic catching but maybe I'll lift each wheel and give them a spin - it's quite a subtle sound so not something obvious.

[Rp0thejester]

If it was catching the arch then it would show on the tyre as wear and also the inner wheel arch. If it's fitted with arch liners then one could be loose but doubtful