Bonus content!
I've had trouble with hot spots on my feet for about as long as I've been doing longer rides. In the very beginning, I chalked it up to the Shimano 600 toeclip pedals I was riding with sneakers (C&V affectation?), and made the switch to SPD pedals and shoes (Giro Rumbles.) These extended the time I could ride before getting hot spots, but didn't cure them. I tried moving the cleats around (as far back as possible was a popular suggestion), which possibly helped a little. Around this time, I read that one's feet can swell while riding long distances, so I started leaving my shoelaces a bit looser. On one brevet in 2015 (I believe it was the 400k), my feet were hurting so bad that I had to take the insoles out of the shoes. This relieved the hot spots but led to some behind-the-knee pain later in the ride due to the change in leg extension. Not long before PBP that year, I bought some Shimano M089 shoes a size up from usual. The stiffness and extra room helped a lot, but as you might guess by now, I still had hot spots and numbness by the end.
More recently, I'd been leaving my shoes looser and looser which seemed to help -- it seems like I really arch my feet when pedalling, consuming more of that excess space than I realized. And I also started to notice that I didn't get hot spots as severely if I had eaten recently. Hmm! Some experiments with snacking more than I normally would for non-stop 40+ mile efforts seemed to confirm that. But what was the mechanism? Did having food in the stomach allow it to compete for more of the circulation that might otherwise settle in my feet? I had already noticed that staying fed helped keep my hands and butt feeling better on long rides, maybe it was just the same for all contact points?
So on the outset of this 300k, I told my buddy "This may be monumentally stupid, but I'm gonna wear my sandals for this ride." He agreed that it was monumentally stupid. But I had committed to the experiment -- my Shimano SD5 sandals were the only bike shoes I'd brought with me. And this facet of the plan worked as well! Taking in calories of whatever type I could on a regular basis kept my feet feeling great for nearly the whole ride. My right foot started to develop a hot spot by that mile 54 mark, but slugging down a bottle of apple juice and eating a snack relieved it. Interestingly, we met another rando at that stop who knew of another rando who had done quite a few 1200's in sandals.
Toward the last 15-20 miles, I started to feel a bit of pressure in my feet again, but we were so close to the end that best practices were starting to fall by the wayside. By the next morning, it was incredible how much I didn't feel like I had ridden 300k.
I've always had trouble eating enough on brevets (I'll blame exercise for blunting my hunger even though laziness plays a role), but now I can use foot pain as a reminder that I've gotten behind on calories and need to eat something.
