In the old book published by, I think, TT Special, that you learnt the course from, it often used to say, of a certain section, "Bumps limit the speed". At one time you had to stay within 2ft of the white line down Sulby Straight or you were in a tankslapper, now you can go anywhere, its so smooth.

I think they should resurface the whole lot with some special "Bumpy tarmac" just for the 100th Anniversary.