In reply to IvanLi:
> Thanks for the answers.
> Pero, in the summer how does the character of the climb on the TR compare to a typical AD route in the Alps? Is it just the length that makes the difference?
Let's take a less serious route like the South Ridge of the Lagginhorn.
1) You have the altitude, which depending on how acclimatised you are can make a big difference. You don't need a particularly early start.
2) You have a simple glacier to cross. But, you'll still need crampons and ice axe, even if there are no crevasses.
3) It's only about 1-1.5 hours to the col where the climbing starts.
4) In good, dry conditions you won't need your crampons, but at 4,000m any time after snow you might find some ice or verglas.
5) The climbing is perhaps not much harder than Tower Ridge, although there's much more scope to go wrong. The main difference is that you are climbing for 5-6 hours, as opposed to 1-2 hours on TR. Perhaps the Cuillin Ridge from Banachdich to Gillean would be roughly the same mental and physical effort.
6) Some sections you can walk, some you can scramble, quite a lot you'll probably be better with slings and running belays as you move together; and you might want do the odd pitch or a couple of abseils.
7) From the summit it's a straightforward but long way back to the hut (about 3 hours).
That's the low end of AD and a good introduction to the grade IMO.
Tower Ridge in summer would be physically and mentally much less demanding.
PS The thing that seems to catch out a lot of British climbers in the Alps is the time. The distances and height gains are often modest by UK standards, but Alpine terrain can eat up the time. Why 5-6 hours on the Lagginhorn S Ridge? It's difficult afterwards to work out where all the time goes. But it does go for sure.
Post edited at 20:30