I’m hoping someone can offer some advice.
I love long distance cycling, and plan to do a 200 km brevet within the next year (with plans to do 300 km, 400 km and beyond as my schedule allows).
I’ve done 180 km+ and regularly ride 80 - 100 km+ at a time (multiple times a month).
My ass, hands, and legs are totally fine until around 130 km, then saddle pain creeps in.
I will admit that doing these distances on a folding bike with 20" tires isn’t ideal, and perhaps that’s just the limitation I have to work with. I do have a suspension seat post and wear padded shorts on those long rides, but again, everything is quite comfortable until around 130km.
Is this a bike fit issue? A padded shorts issue? A small tire issue?
No, but not because of comfort. I find that regular shorts or just non-padded lycra causes me to sweat through them to the point where it looks like I’ve pissed my pants in less than an hour of riding. Padded shorts give me some buffer before moisture can be seen through them.*
If I were to guess, I’ve probably done my regular 60 - 80km rides without padded shorts at a reasonably comfortable level (I honestly don’t even remember).
On this bike, without padded shorts and with several other saddles than the one I’m using now (Brooks C17 carved), it gets uncomfortable much sooner.
Sounds like a good thing to try. Good luck!