FindinFreestyle wrote:
You are not going to answer any questions regarding proper crank length range by the methods you describe. Here is what you need to know. I realize this is a waste of time, but here it is: 1. The only way to intuitively understand the benefits of shorter cranks is to have a competent fitter utilizing proper equipment take you to the limit of your current crank length before making a change. In other words, if your fit is not at least in the ballpark of optimized, you probably won't notice much, or even worse, you might have a different experience than if you were close to optimal.
2. When done as described above, about 80-90% of riders are going to prefer a crank length from .5 to 1.5 cm shorter than what would typically come on a stock bike in their size.
3. Many of the things previously mentioned are important, especially riding a lower / more aero position, but the first thing the fitter and rider need to determine is "Do you prefer this?". It is the same question asked when seat height, setback or drop is changed.... How does this effect your intuitive sense of pedaling? After which, we can look at the power, how much drop you can ride, etc. First is always rider feedback.
4. There is no perfect crank length, or if there is I don't know how to find it. I do know how to find an acceptable range for a given rider. Acceptable here is synonymous with appropriate, and NOT the same thing as aggressive. The #1 thing I look at is how close to the FIST described 100 degrees of hip angle can we achieve with this rider? Is their lack of mobility or excess belly fat getting in the way of this angle? If we have a lean and reasonable limber rider who just can't seem to pedal effectively when we dip below 105 degrees of hip angle, crank length absolutely becomes the prime suspect.
5. Crank length is often the most important metric I change for riders under 5'6" or so. The majority of these riders are what I term "massively over-cranked". These riders typically reduce crank length from 1-2cm, with the shortest commonly available length of 145mm (Cobb) being frequently used for riders under 5'3".
6. Generally, not one watt is gained or lost from a crank length change. Now if the crank was so long that it was basically contributing to a lousy fit, sure, we will probably find some power, but that is more a function of fixing the overall fit. This leads me into one of the final points...
7. Crank length is not fundamental to your bike fit. Seat height, setback, reach to bars, drop to bars ARE your bike fit. Nail those four and you've got a fit. Saddle selection, aerobar shape/tilt/width, crank length, cleat position etc are all secondary factors. Crank length is probably the most important secondary factor for the majority of riders, right up there with saddle selection. What this means is that if we determine 160mm is in your ideal range, your bike fit still exists on 175mm cranks. Saddle height will change, drop will change, set back will change and even reach may change with the less optimal length, but the fit isn't ruined by the wrong cranks. If cost is an issue, we adjust the saddle, ride a bit less drop and advise to change the cranks when you can.
8. Adaptation time for changes in crank length is about 3-5 minutes. Thanks, agree with the comments.
A couple of things I might have felt.
I had a crappy bike fit. It is getting better. After todays race, going to raise it even more.
Going down from 200's has helped me a lot I think from being able to push the pedals better, whatever that means.
But, as I am going through the test process, I am finding interesting data, as posted in my other thread, about HR vs crank lengths vs rpm.
So it may not be 100% crank length is ONLY fit. Since most folks/fitters would never spend the time I am spending, let alone having the equipment
to do the testing I am doing, not sure how anyone can say their may be more to crank length than just fit.
As Sutton said, he believes most folks race at too high an RPM. As I have now raced my last two races around 70, vs the 90's I used to spin, it is interesting how the bike feels. Not enough data points yet, but gathering.
Since my bike fit, I am a lot better positioned than I was. Seat way back, shorter cranks, and higher seat.
I do admit having more stuff to check power, hr and rpm on the bike while racing would be nice now. :(
Again, all great inputs, and I do like the one that shorter folks have probably been on longer cranks which has not been the best for their fit.
I am going to copy, assuming it is okay, your comments to the other thread I have done on crank lengths, since yours is the most detailed one I have seen yet.
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