I'll add my thoughts here... as I'm of the belief that a fat tire at low pressure will indeed be harder to push up a hill, just based on my own experience, no data to support it, although I also believe that real life experience is a pretty good "data point" in itself. So, what is "rolling resistance" besides friction between the tire and road. Let's assume a constant contact patch for a moment, but a 100lb rider vs a 200lb rider. Is there more rolling resistance with the 200lb rider? I think so. Suppose you're sanding a board for example. You can apply light pressure (less weight), or really get into it and apply a lot of pressure (more weight). Which one produces more friction... I'd say the one where you're applying more pressure. Ok, so if you agree with that, assume there's also this thing called gravity... I know it exists and being a big guy it affects me more than the little guy, at least that would explain why most "climbers" are "little". Going up hill is simply harder as the weight increases for sure, but also due to gravity. It doesn't take much more effort to keep the 200lb guy rolling on flat ground than it does to keep the 100lb guy rolling (on flat ground). But that all changes dramatically as soon as a hill looms ahead, thanks to gravity. Aero factors at uphill speeds are pretty negligible (you can argue this if you want). So, even with tires with the exact same contact patch.... wouldn't the heavier rider be creating more friction between the tire and the road, due not only to the extra weight, but also by the evil forces of gravity as he ascends trying to catch his li'l fuker of a friend bouncing on ahead.Hexsense wrote: ↑Tue Oct 02, 2018 4:06 pmHeavier, yes. But more rolling resistance too? Do you have any evidence or explanation?
You'd feel more of the rolling resistance difference when you climb, because the speed decreases and wind resistance is shrinked to a point it can no longer overshadow difference in rolling resistance in the total drag. You'd feel more of the difference, yes. But i don't see rolling resistance increases when you go up hill, more like it'll decrease as you also decrease the speed.
So, yeah... I think rolling resistance is indeed greater going uphill than it is on level ground because of two things... absolute weight, and the effect of gravity on that weight.
Just a thought.