747 vibration on take off

[windy1]

Departing Miami on BA we couldn't help but notice a severe cabin vibration just before lift-off. We were seated midships and most pax around us were quite startled and convinced something was amiss.

We are quite experinced pax but this was a novel experience.
Suffice to say cabin crew totally unmoved and journey completed without incident.

What might have caused this and to what extent is it normal 74 behaviour?

[Cleared_to]

Could have just been a rough part of the runway, nothing to worry about.

EDIT-spelling :)

[Fright Level]

Quite often the nosewheel will run across some centreline lights prior to rotation or as the aircraft rotates the rear wheels will hit a rough part of the runway. As the gear is selected up, the wheels wobble transferring the vibration to the cabin. Nosewheel is particularly bad as it isn't braked until it is retracted into the wheel well.

Nothing to worry about.

[AlanM]

We had it quite "severely" when flying from JNB with the world's favourite airline last month. (B744)

What you have described was probably a pressure inbalance on the 2 nose wheels causing vibration.

At least that is what the Capt said!