For me it's about flexibility. I know I can do consecutive days riding; I did London to Edinburgh (plus a bit further at each end) in under 3 days earlier this year. I was still feeling relatively fresh when I woke up on the 4th day (to get the train home). It will certainly be easier starting off each day given the enthusiasm that will be around on the real event with hundreds of cyclists about.
I've also recently done a very hilly 600 (8200m climbing) with two 15 minute powernaps and felt ok at the end (maybe not so great during the middle, but I pushed through the bad patch and came out the other side).
Having done both of these I'm better equipped (in my head) to decide what to do on the day. I may decide to ride through the first night and go all the way up to Dalkeith (720km) in one go with just a couple of naps. I can then get 10 hours of good sleep and then have 3 days to slowly bimble back down to London.
Or, I may do the bare minimum of 288km per day and try and minimise night riding in favour of 6 hours sleep each night.
400s are odd distances because there often not long enough to build up enough time in hand to have a good sleep (unless you're fast), so they are very good for getting used to riding with a bit of sleep deprevation.
As I said before, I'd agree that it's not necessary to do a 400 or a 600, but they introduce you to different aspects of long distance riding that you won't necessarily get even with consecutive days of 200s or 300s. Nightime hallucinations are one thing, but getting them at 4pm is just plain freaky.
I've also recently done a very hilly 600 (8200m climbing) with two 15 minute powernaps and felt ok at the end (maybe not so great during the middle, but I pushed through the bad patch and came out the other side).
Having done both of these I'm better equipped (in my head) to decide what to do on the day. I may decide to ride through the first night and go all the way up to Dalkeith (720km) in one go with just a couple of naps. I can then get 10 hours of good sleep and then have 3 days to slowly bimble back down to London.
Or, I may do the bare minimum of 288km per day and try and minimise night riding in favour of 6 hours sleep each night.
400s are odd distances because there often not long enough to build up enough time in hand to have a good sleep (unless you're fast), so they are very good for getting used to riding with a bit of sleep deprevation.
As I said before, I'd agree that it's not necessary to do a 400 or a 600, but they introduce you to different aspects of long distance riding that you won't necessarily get even with consecutive days of 200s or 300s. Nightime hallucinations are one thing, but getting them at 4pm is just plain freaky.
