I've never really shot sports before, but I did take some pics when the torch came through last week.
What I found was that I used the 24-70 the most, especially when the torch itself comes through as you couldn't get a clear shot when it was far away - at least I couldn't and I was standing on a high vantage point.
A telephoto was useful for picking out details in the crowd, but really a wide was the best option. In terms of settings - definitely use continuous if your camera does it - mine does but I forgot to switch it to that so only got one good shot!
Also, when it comes past, it comes and goes really fast so you have to be ready. I got a great shot of the guy as fortunately there were no barriers where I was and I could more or less stand in front of him.
I'll put up my pic when I get a chance.
Hope that helps, but do enjoy the day as there was a great atmosphere (and pretty well organised). From my experience and others that I've spoken to - get there early.