norcalscot

I'm kind of late to this thread, but I thought I'd put in my 2 cents worth...

I've been riding 'ultras' (I really hate that term) for a little over 12 years now, as well as randonneuring. In that time I've done three 600Ks in less than 24 hours, as well as five Furnace Creek 508's and two Race Across Oregon's, where I covered more than 300 miles in 24 hours (325 minimum, 400 maximum). I ride Brevets with friends, and the ultras have all been solo non-drafting. All of these are 'total elapsed' times, not moving averages.

With practice, I believe covering 300 miles in 24 hours is something that many people can achieve. As several have pointed out it does require that you learn to properly pace and fuel yourself. I usually do an almost exclusive liquid diet, and for me 275 to 325 calories per hour is what my stomach can sustain over the long haul - YMMV.

I would encourage anyone who's thinking of doing a 24 hour (or greater) event to go for it! The sense of personal achievement you will gain from such an accomplishment is something that will stay with you forever.