Watch the pit lane video on the red button during live events. Pictures of drivers are shown with all their stats/weights/birth.
If my source was wrong, I apologise. And if so, that particular figure must be out of date. I must admit, I raised an eyebrow at being told Vettel was only 58kg! Even so, in today's world of F1, 10kg is still significant, and set to become more so next season, not that it'll bother Webber.
In Ted Kravitz's qualifying notebook he said Red Bull are going to have to make a wider cockpit next season to accommodate Ricciardo's fat thighs. He hasn't even got there yet and he's causing problems. please log in to view this image
It's okay... they are having to redesign the steering wheel to accommodate Vettel's finger. Swings and roundabous. #itsajoke