Oh no, not another one...
Megane Cab Vibrations through steering wheel
Yours sounds slightly different though
Firstly, I would completely rule out the rear discs.
If it was a misfire, the idle would be rather slow, the engine would be shaking, and listening at the exhaust tailpipe, you would hear a rhythmic blowing rather than an even burble.
But then again, a misfire (
pack, plug, injector, whatever) would most likely be evident at all engine speeds, not just over 40mph, and I'm not sure you would even make it to 60mph...
So, it does sound to me like you might also have a buckled wheel, try swapping front wheels with back and see what happens
Sorry, I just noticed... Welcome to the forum!