Its been a few years since I did an IM; I remember feeling battered for 3 days but getting better after and normally on the bike by Weds
Reason I ask is a friend wants me to do a 3 day event with him; will be c 6-8 hrs a day riding
Not sure its the cleverest idea; but would be a lot of fun
For what its worth the bike leg is my strongest discipline
For all you Hamburg chaps; how you feeling a week or so after the event?
Well it depends how much of the marathon you run in most cases. The more you ran, the more battered your legs will be. I don’t feel like riding 20 hours over 3 days at the moment; certainly at any pace. I’ve done 40 min very easy on a Wattbike, and two swims so far since Wednesday.
No.
I did Ride London 100 I think two weeks after IMUK and the last half was a real ball ache.
Lanzarote ruined my undercarriage, I didn’t look at a bike for five or six weeks.
The real question IMO is not whether you can but whether you would you want to?
And the answers is no! 
Some clearly can, but answer for me is a definite no. I seem to struggle after, I’m still pretty ropey 3 weeks on from IMUK. Fine day to day and moderate exercise but wouldn’t want to do back to back big days yet like that, would probably make me miserable.
When doing extreme IMs I am normally quite ok 2-3 days after, with full power back in 5 days. But it’s at a lot lower effort and hence less strain despite being out for much longer. I think Hamburg would be worse since it’s flat and fast.
I think you’d struggle on the power. Legs won’t be there. If he rides at 50-60% of your level then you might stand a chance. 
Thx - we will both liking ride at 60 % FTP because its 25hrs over 3 days
But I bet his 60% is higher than my 60%
Am conflicted; its not the sort of thing you want find out half way through that you are shagged!
Never a good position to be in, in any walk of life 
If you go easy on the IM then it might not be a problem. But what’s the point of going easy in an mdot IM?
Agreed; if I do it I would not want to hold back on either
As you say, otherwise why even do it
I wouldn’t consider trying to run within a week of an IM, but I usually find that I’m really strong on the bike after a few days of rest. My legs usually feel a bit heavy, but there’s plenty of power there when I need it and if I’m riding with other people I generally find that I get stronger relative to them as the ride goes on.
Basically, your friend needs to find another ride buddy 