Originally Posted by
livedarklions
Right. But that's a somewhat different calculation when on a multi-gear bike. I think everyone has to calculate this zone for themselves based on experience and knowledge of their own physical characteristics and how or what they ride.
I think for me the calculation is that I more than make up for the increased aerobic demand of the increased force (if that indeed happens) by the decreased demand caused by the decrease in RPMs. I think this is varying a lot from person to person.
In my experience, there is a definite tipping-point where the decreased frequency no longer compensates for the increased force, for aerobic demand. I completely agree that this varies from person to person. It also varies with training.
I found a "brute force" kind of fitness from riding a singlespeed where my endurance for pushing low-rpms improved. I took a break from riding the SS for a while, and my only MTB rides were on my geared bike. My aerobic fitness was improving (based on PR times on a climb I do regularly), but when I got back on my SS, I couldn't maintain pushing the big gear the way I had before, and my climb time was slower than the last time I had ridden the SS, even though I was in better aerobic condition.