Originally Posted by
Wilmingtech
This is not true. In the same gear the pedal speed (Not Cadence) must be faster with the longer cranks to keep the same cadence. By reducing the length of the cranks it does a few things, slows the pedal speed and opens the hip angle and reduces the knee flex over the pedal stroke. It's not going to give anyone more power or make them go faster but at the same pedal speed as the larger cranks the cadence would be higher thus increasing endurance over the 15 miles of climbing. Granted this is very marginal as we are talking about a 2.5mm difference in crank length which amounts to a 5mm overall circumference when looking at pedal speed.
The reasoning for the saddle forward was two fold. To make up the slight difference in saddle height with the shorter cranks and to open the hip angle for the longer climbs. It was 1/2cm of difference and was actually pretty comfortable for climbing.
Typically I try to spin at 75-80 rpm when I have steep climbs (+6%). In anything less than a 6% grade, I can typically sit at 85-90 without issue. My bike is typically setup 50/34 x 11/28 when I am in the hills which is most of the time. The struggle I had on this ride specifically is that it was 15 miles at 6-8% grade. I just don't have a regular ride that has a 2 hour climb at +6%. So my cadence slowly dropped over the length of the climb. .
Knees don't wobble. Just had a bike fit a month ago and the fitter started with KOPS (he was more of a "classic" fitter). He had me slide the seat forward during the fitting as this frame (As mentioned in the OP) is at the large ends of frame sizes for me. Sliding forward shortened my reach and opened up my hip angle a little bit and gave me a little more power comparative to where the seat was previously. I thought it interesting as well that I didn't get cramping in any other muscle groups besides the satorius. Toward the end of the final climb I had to massage them a little bit while riding to keep them from cramping up.
Here's a simpler way to think about crank length.
Crank length is simply a gearing issue. We can use a standard "reductio" argument here. Given your current gearing, could you do that climb faster with 100mm cranks? No, you couldn't. You'd be hard pressed to just turn the cranks. Without a gearing change, it becomes a torque issue. If you can reduce the necessary torque with sufficient gearing, then any crank length will serve. Then it becomes a biomechanics problem, which is very difficult to solve because of the training issue. We become accustomed to a certain position, certain rpms, a certain crank circle, and only prolonged training with that new position, cadence, and crank circle can resolve whether or not it generates more power over a particular time span. This is not a simple problem. Hence the standard formula of: inseam in inches * 5.5 = crank length in mm. Most folks just use what came on the bike or else use the formula and see if that works for them. Or not.
Since your standard climbing cadence is considerably faster than 65, gearing your bike lower to allow a faster cadence and thus lower force would have been helpful. Just putting on shorter cranks doesn't mean you'll spin faster on a climb. To the contrary, because you can't spin faster unless you gear lower. One has to accept that cassette size is a visual for others which doesn't matter to you as you can't see it.
The climb from the Deli Stop to Sunrise is good training. I was at the ranger station a couple years ago, talking to a tandem team. They were about to start their 3rd repeat of the day. Can't say that tandems can't climb. An exceptional day ride is the clockwise loop from Ohanapecosh over Chinook and then White passes. People park in the equipment yard, to the left going in.