So, Zakeen, can you pull yourself away from your long hours of being a Protour hardman and take a minute or two to fill us in? And if you have any extra time, how about a step-by-step how-to to help guide us would-be DIY carbon shoe builders?
I dont like to say to much, so you are right in that way
But to say a few things I disagree of, which does not mean I am correct, I watched your video Cyclespeed and your points on why its better to have shorter cranks were:Leg doesn't come up so high so you can get your torso lower just by having shorter cranks.
This has nothing to do with crank length, I run super long. Then I ride a frame a little smaller then I should, but I must do that so I can have a shorter steering tube, meaning my stem, without spacing is as low as possible and then I still have a negative angled stem. If I ran the a bigger frame then I wouldnt be able to get my handle bars so low(bigger frame bigger steering tube). So having said all this. I really have an extreme low bars and still my legs dont hit my torso. I did however move my saddle more forwards which opens up my hip flexors and tilled down my saddle which helped even more.Cornering, you have less ground clearance.
Im able to race without this problem.To get maximum power is hard and fast peddling and its easier to maintain that on shorter cranks because you said it is a lot easier to maintain that circle of high speed circle. If you don't have to do a great big circle with longer cranks which is putting a lot more strain on your joints
This gets more interesting. Power output is Watts equals RPM X Torque. So having a longer crank arm requires less Torque/strain( which I believe is better for your joints ). Doing smaller circles to maintain higher speed I disagree a little. Legs are going up and down, like pistons in a engine. Every time they go up, stop and down they lose energy and the muscle has to re-fire again. I feel its easier to maintain a larger circle.You mentioned that if a shorter crank does a 12 to 6 oclock rotation then the wheel travels the same as a longer crank doing the same. Then you say that people with longer cranks are using less force(which is the whole idea), saving energy and must be good.... on that rotation. Then you say: But no its just a simple question of gearing, because all you have to do for the shorter crank feel easier again is just change up a gear. The shorter crank becomes easier and you are back to the same thing and you have no advantage of having a longer crank.
This is where I think you are wrong. If you are at the same place by simply changing up the gear, then yes you are right, the amount of force would be the same for the smaller crank to do that 12 to 6oclock rotation in a smaller gear compare to the longer crank in a bigger gear. Force might be the same(depending on gearing differences). However, the wheel rotates far longer in a bigger gear then in a smaller gear. So you yourself say right there, that there is a difference. Same force, different crank length, different gearing's. But one gearing has a longer rollout would mean that difference in rollout is the advantage of longer cranks. You would rider further with the same force applied on the crank.
Now I know its not as simple as that, but yourself there says it.
How I got to my crank length were pretty simple. There is no real way of measuring the workload of a body(yes we can throw on SRMs and guess the body is about 25% efficient and work out the total amount of calories spent through an SRM is multiplied by 4 to give what out bodies used in energy to produce those watts, but that's still guessing, they do say its very accurate). But after speaking with a mechanical engineer they set up my bike to be efficient. Then I went and spoke with then tested with Bio mechanic and asked them how do I become as efficient as possible to spin this position. I was able to get my position based on that. I dont want to say to much but some food for thought:
Your muscles are at most powerful as operate with greatest active tension when they are close to ideal length (normally their resting length). So to get the maximum out of the quad its best to be at maximum effort from 2:30 oclock to 6 oclock or while standing even 1 oclock and imagine the leverage on a longer crank while standing
Cycling races are long... super long. I could hit the gym and hit hard weights or I can hit slightly less hard weights and be there longer....
I have my cleats further back, seat forward and all this combines with my position and also my longer cranks, Then you look at femur to crank length ratio that just destroys everyone theories all together....
Im not saying longer is better, I personally tried 172.5, 175, 177.5, 180 and 185mm. I ride with what I feel best. You should ride what feels best for you