I'm presently reading up on people doing 100 km in a day
hard to say how I'd go - if I'm up there with my fitness - I'd say I'd be able to do it ok - but, when you read reports - well - one doesn't know until one tries it.
Many say the first 50 is easy -- which I've found - 50 is easy. When I've done that - I have always thought - yeah - I reckon I'd go another 20 easily enough -
but, there's a difference between 70 and 100
my cruise speed for 50 km in one day is 6km per hour - as good as almost exact.
I stop for a few coffees and a few little feed breaks.
doing 20 a day is very easy - back the week before last - I did 20 a day - for either 4 or 5 days straight - can't remember which - easy