Fascinating topic!
Only a few rides past that point, but hoping to do some “faster” 300k+ rides in the future. I feel like my legs feel the best (compared to others) after the 200km mark, so maybe I am built for some relatively long miles.
Some data points:
Not sure what original post’s question is. However, if it helps, I did a 12hr Time Trial a couple of months ago. 252miles, average speed 21mph, IF 0.68, off a 225w FTP. Average power 146. NP 154. That includes coasting for an hour down hills. I was stationery for 11 mins for food and pees. Do these graphs help the conversation?
I have no idea what my average over 24 hrs might be. Definitely I would be going slower/more econimically.
Graph with power curve, compared with racing season’s power curve (steps at 25m, 50m and 100m TTs of course)
Graph with zones. showing power in the 12hr TT
I did similar 12hr TT (236 miles) 2 years ago so may post that as well.
Lol, are you insane? 
Can I ask why?
Going for the Triple Cown? I’m planning on doing the Eastern Sierra double as my first. I’m still not sure if it’s a good idea! If that’s one of your three, I’ll see you in June.
Yes, I want a triple crown jersey. Trying to figure out which 3 to target. Possibly Hemet in April, Davis in May, and Eastern Sierra in June.
My wife hung up a thing in my pain cave that literally says, “You’re crazy” 
. It was height of covid, all my events were cancelled, and with WFH started doing longer indoor rides, and just eventually decided to see how long I could push it. I’d decided to do a 200 miler solo just to have something on my calendar, so it helped me gauge what I’d be able to do for that power wise.
All my 12 hour efforts seem to be part of multiday bikepacking trips, so not sure how comparable they are. The pace can’t be too high since I need to ride the next day as well. There’s also all the stopping involved with shops, cafes, restaurants, sights, etc.
This year my summer solo bikepacking trip ended up being 1000km of pavement, gravel and a bit of singletrack across Finland over 5 days. All except first day had total elapsed ride time of >12 hours and power curve had power at ~100w@12h for each day and got a couple of >12h power PRs. FTP was ~276w (probably a couple of watts less)
Day 4 had the highest 12h effort at 105w.
Day 5 was longest at 103w@13h45min
Closest proper long ride effort has probably been “Saimaa Cycle Tour” event this year. 285km, 147W@10h15min. I wasn’t completely destroyed at the end and there was a lot of stupid pacing involved, so I’m pretty sure I could get similar power numbers for a full 12 hours with proper planning.
Remarkable
… not so impressed after the first statement 
Well yeah but most are unable to comprehend how aero Jason’s bike was. 
That model bike is a real mile gobbler.
12 hours of moving time, 180w avg. 202w NP, about 60.5% of FTP. managed to minimize my non-moving time for the race down to 19 minutes! Was good for 2nd place. Rode most of the race solo and didn’t hammer too hard since the Leader/winner stuck an attack at mile 20, knowing I wasn’t gonna chase him down alone, rode easier in case I got caught so I would have the legs to jump in.
I’d be curious to see what I could do for 24hrs, but I am such a routine sleeper the overnight part would be rough for me. No problem riding at 4am, but 10pm I think I’d struggle.
same here, so I’ll work on seeing what I can do for 12 hours.
Look for a 12 hour event that starts at midnight. Some promoters do this from time to time so that the 24 hour and 12 hour races finish at the same time. A midnight start is kind of the ‘half way’ compromise. You get a chance to feel out the midnight and witching hours riding in a less fatigued fashion.
It does give you a feel for it…but more than that a midnight start for a 12 hour just gives riders the confidence they need. Pretty much everybody can do the 24hr overnight thing. They just need the confidence to give it a go.
The only caveat I’ll add is watch out for the cold! The cold will hit you a lot harder in the witching hour. And not just as a mental issue…you really will be more susceptible to hypothermia.
I am currently training for a 10hr+ gravel event and have looked at my own power curve and that of world class ultra endurance athletes (although the two have nothing in common).
My power curve seems to flatten off at around 200W and stay there for quite a while. I haven’t done anything longer than 9 hours of riding and had 198W Np (with off road riding making a even power output very difficult, and the avg therefore being much lower).
That would be something like 55 to 60% of my 1hr power.
Looking at the elite, many of them don’t have a higher FTP than I do. However, the power curve just flattens off at a much higher number (like 250W) and stay there for almost ever. For me, that’s totally crazy. I have done 5 hours at 240W and it was the absolute maximum of what I could do. Considering that some people would do such power for 10 or even 24 hours is absolutely beyond me.
I guess it has to do with genetics (so if a long effort suits you better than a shorter effort) but of course training. So I don’t think it necessarily has to do with FTP, but rather training to maintain a high power for long hours.
) for the 12h40mins moving of the 312 I did 185w (or then 3.02w/kg) adding in the 50mins stopped it falls by the Strava calculation to 175w (then 2.98w/kg).
