Re: My testing to try and find best crank length with my Velotron [h2ofun] [ In reply to ]

Oct 22, 17 14:30

Post #326 of 1333 (11252 views)

Interesting racing today. 175’s. Bike shoes.

Worked on keeping my RPM’s down. Sure wish I had some type of meters so I could see my RPM, power and HR.
I have not gotten my garmin going again yet on the bike since I changed the cranks.

What was really interesting is at one point when I was low RPM’s, and on the flats, I tried to get another gear to gear down.
Guess what, nothing was there, I was already in the 50/11. So crank length and rpm’s clearly can impact a choice of gearing.

I wonder if there is data that could show using one crank length for the hills and a different length for the flats?

Fun stuff. Sure the right time of the season to be playing with this stuff.

I tried 150's on my Velotron on Friday. Was pretty tired so the HR was pretty high. Will give it a try again hopefully tomorrow.

Dave Campbell | Facebook | @DaveECampbell | h2ofun@h2ofun.net

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Re: My testing to try and find best crank length with my Velotron [h2ofun] [ In reply to ]

Oct 22, 17 15:42

Post #327 of 1333 (11211 views)

Decreasing your crank length has increased your gain ratio and your effective gearing:

https://www.sheldonbrown.com/gain.html

http://www.slowtwitch.com/...nd_Gearing_4095.html

That would seem to run counter to what you experienced, i.e. running out of gears.

It's possible that with the hip angle more open on shorter cranks, you're able to put out more power.

If you decreased your cadence more than would be made up for by the increase in effective gearing, that would explain why you ran out of gears.

In trying to keep my cadence super low, I moved from 172.5 to 155 cranks and increased my chainrings from 52/36 to 54/39, which was somewhat hard to find on 110bcd.

Coach at TriForce Triathlon Team: https://www.triforceteam.com

Re: My testing to try and find best crank length with my Velotron [h2ofun] [ In reply to ]

Oct 22, 17 17:00

Post #328 of 1333 (11180 views)

Great inputs from another of my threads I wanted to capture here.

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.

Dave Campbell | Facebook | @DaveECampbell | h2ofun@h2ofun.net

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Re: My testing to try and find best crank length with my Velotron [asellerg] [ In reply to ]

Oct 22, 17 17:07

Post #329 of 1333 (11180 views)

asellerg wrote:

Decreasing your crank length has increased your gain ratio and your effective gearing:

https://www.sheldonbrown.com/gain.html

http://www.slowtwitch.com/...nd_Gearing_4095.html

That would seem to run counter to what you experienced, i.e. running out of gears.

It's possible that with the hip angle more open on shorter cranks, you're able to put out more power.

If you decreased your cadence more than would be made up for by the increase in effective gearing, that would explain why you ran out of gears.

In trying to keep my cadence super low, I moved from 172.5 to 155 cranks and increased my chainrings from 52/36 to 54/39, which was somewhat hard to find on 110bcd.

My guess is my cadence was so low. Meaning, no way could I spin a 50/11 at 90 plus RPM on the flats. But at 70, with a tail wind, all I know is what I tried to do.
Just never had that happen before.

Your comment on going to shorter cranks and increasing your rings is interesting. That clearly was my first thought. But I was thinking maybe I would have to put
the 53/39 130mm cranks back on. But, am still concerned how this shorter cranks are going to work in the hills, which I have yet to make the time to see how it feels. I need to get off my duff.

So where did you find 54/39 110 rings?

Thanks

Dave Campbell | Facebook | @DaveECampbell | h2ofun@h2ofun.net

Boom Nutrition code 19F4Y3 $5 off 24 pack box | Bionic Runner | PowerCranks | Velotron | Spruzzamist

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Re: My testing to try and find best crank length with my Velotron [h2ofun] [ In reply to ]

Oct 22, 17 18:12

Post #330 of 1333 (11152 views)

I bought the 54T and 39T rings separately, but both were Rotor, the NoQ. One was from Art's Cyclery and one was from Chain Reaction Cycles.

Coach at TriForce Triathlon Team: https://www.triforceteam.com

Re: My testing to try and find best crank length with my Velotron [h2ofun] [ In reply to ]

Oct 29, 17 9:52

Post #331 of 1333 (11038 views)

Is interesting spending more time spinning 150mm cranks. They might be causing me less knee strain on my bad knee compared to 175's, let alone my 200's
Being sick means the data does not mean much but what the heck.

Hoping to get some prototype cranks from Frank to use for more data collection on how efficient my pedal strokes are via the testing.

Got to somehow make the seat post extension on my Velotron go higher. At my height, and crank length, seat is not able to go as high as I want it to.

Dave Campbell | Facebook | @DaveECampbell | h2ofun@h2ofun.net

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Re: My testing to try and find best crank length with my Velotron [h2ofun] [ In reply to ]

Oct 29, 17 13:30

Post #332 of 1333 (10990 views)

Why are you trying to keep cadence so low in a race?

Re: My testing to try and find best crank length with my Velotron [iamuwere] [ In reply to ]

Oct 29, 17 14:00

Post #333 of 1333 (10968 views)

iamuwere wrote:

Why are you trying to keep cadence so low in a race?

Why not? What is low? Sutton sure believes that lower cadence is better for most athletes. Lower cadence for the same power is giving me lower HR's.
I have always believed the line that one has to spin high RPM's. But why?

It did not hurt me in my first race I was able to try it.

If you can put out the same power with a lower cadence and lower HR, is this not worth considering, as Sutton says?

Dave Campbell | Facebook | @DaveECampbell | h2ofun@h2ofun.net

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Re: My testing to try and find best crank length with my Velotron [h2ofun] [ In reply to ]

Oct 29, 17 15:08

Post #334 of 1333 (10940 views)

h2ofun wrote:

Why not? What is low? Sutton sure believes that lower cadence is better for most athletes. Lower cadence for the same power is giving me lower HR's.
I have always believed the line that one has to spin high RPM's. But why?

It did not hurt me in my first race I was able to try it.

If you can put out the same power with a lower cadence and lower HR, is this not worth considering, as Sutton says?

Lower cadence shifts load from cardiovascular to legs and uses fewer calories per mile. Higher cadence shifts load from legs to cardiovascular system and uses more calories per mile. Using a lower cadence will lead to more fatigue in the legs and likely slower run times. Higher cadence may lead to your cardio system blowing up during the run. It's all about finding the proper balance. I personally have better cardio endurance than I do leg muscle endurance, so higher cadence plays towards my strengths.

Re: My testing to try and find best crank length with my Velotron [PVD04] [ In reply to ]

Oct 29, 17 15:14

Post #335 of 1333 (10930 views)

PVD04 wrote:

h2ofun wrote:

Why not? What is low? Sutton sure believes that lower cadence is better for most athletes. Lower cadence for the same power is giving me lower HR's.
I have always believed the line that one has to spin high RPM's. But why?

It did not hurt me in my first race I was able to try it.

If you can put out the same power with a lower cadence and lower HR, is this not worth considering, as Sutton says?

Lower cadence shifts load from cardiovascular to legs and uses fewer calories per mile. Higher cadence shifts load from legs to cardiovascular system and uses more calories per mile. Using a lower cadence will lead to more fatigue in the legs and likely slower run times. Higher cadence may lead to your cardio system blowing up during the run. It's all about finding the proper balance. I personally have better cardio endurance than I do leg muscle endurance, so higher cadence plays towards my strengths.

Great points, and that is what I am going to try and figure out, for me. If I can knock 2 minutes off my bike time, and add a minute on my run time, might be worth it.
But only one way to find out, and that is to change stuff and see what happens. Why not, I sure have nothing to lose on my bike times. :(

Lower RPM sure did not seem to hurt Chrissie on the bike, let alone her run times for Hawaii.

I have zero leg muscles, but am trying to see if I can improve for next season. Already have added squats into my daily training. Have a much better bike fit.
May put in some hill repeats for next season. But yep, that is the big question, how much, if any, will this hurt my run. The first try with 175's in a race, and limited aero, and lower RPM, got my a 18:44 for 3 miles which was cool. My last race had a little longer 5K run time, but still was pretty good for my age.

So again, why would I not try some different things. Been doing this for 20 years and it can get pretty boring without something to try new.

I might find I want to go back to 200's and higher RPM if I try a few races and suck. :)

Dave Campbell | Facebook | @DaveECampbell | h2ofun@h2ofun.net

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Re: My testing to try and find best crank length with my Velotron [h2ofun] [ In reply to ]

Oct 30, 17 5:20

Post #336 of 1333 (10843 views)

Sutton advocates low cadence for AGers doing full Ironman, where you need to conserve calories and HR for a 9-16hr day. (Well, actually, he doesn't advocate low cadence... rather, his belief is that AGers should just ride at whatever cadence feels natural for them (which is usually lower) and not worry about trying to "spin" like roadies at +90 rpm.)

For sprint races that you do this is a non-issue. Generally, the shorter the race the higher your cadence should be for optimal pacing.

For someone "without muscles" you would probably benefit from higher cadence. Lower cadence requires more strength and muscle recruitment per rep than "spinning" at the same Wattage.

Re: My testing to try and find best crank length with my Velotron [SAvan] [ In reply to ]

Oct 30, 17 7:09

Post #337 of 1333 (10792 views)

SAvan wrote:

Sutton advocates low cadence for AGers doing full Ironman, where you need to conserve calories and HR for a 9-16hr day. (Well, actually, he doesn't advocate low cadence... rather, his belief is that AGers should just ride at whatever cadence feels natural for them (which is usually lower) and not worry about trying to "spin" like roadies at +90 rpm.)

For sprint races that you do this is a non-issue. Generally, the shorter the race the higher your cadence should be for optimal pacing.

For someone "without muscles" you would probably benefit from higher cadence. Lower cadence requires more strength and muscle recruitment per rep than "spinning" at the same Wattage.

And great points. I clearly ran off the bike great with spinning high RPM with long cranks. The question for me now is can I make some changes on the bike, with fit, cranks, and maybe RPM, have a little faster bike, and maybe a little slower run, but be net faster to the finish line, which is what the game is all about.

Last weekend implied maybe the combo was overall a little better, but until I do a number of races, especially in the hills, will see. But I have nothing to lose by trying, only possible gains to be made and data to maybe show, for me, what is better. I will not be selling my 200 cranks but I already feel I have a much better fit without those long suckers, but, ...

I do see I have lower HR;s with lower RPM. Can I find a balance where I get this advantage but save my legs. Data will show. Maybe good. Maybe bad.

I just have never seen anyone else make the time, and change commitments, to see what might work the best. Now easy to try lots of different cranks lengths as an example.

Thanks

Dave Campbell | Facebook | @DaveECampbell | h2ofun@h2ofun.net

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Re: My testing to try and find best crank length with my Velotron [h2ofun] [ In reply to ]

Oct 30, 17 7:14

Post #338 of 1333 (10787 views)

This was posted in another thread which I thought was better here.

So the stated goal of the study is to optimize crank length to minimize drag and increase power output. Minimizing drag isn't really stated anywhere that I can find but that's pretty important. Important things to note:

1) you race with your cranks locked, as stated previously
2) you race in the aerobars, or at least you should, otherwise you're wasting your time
3) power output and physiological impact of riding in the aerobars is different than that of riding not in the aerobars, especially if your cranks are too long.

The fact that the first round of testing was with unlocked cranks and not in aero means that the collected data is useless.

Couple this with the fact that your posted fit videos still don't have correct seat heights or locations (basing this off of the statements of people who know more than I do), you're still not getting data that will lead to the desired outcome. I must admit, I was somewhat incorrect in my earlier statement. You're not really varying multiple things. However, there is enough uncertainty in your test methods that you will not achieve your stated goal by the methods you've been using.

These are all great comments and questions.

I can ride cranks, locked or not, basically the same since I have been riding for so long.

I did change my bike fit and posted a video. So if your comment in on the first, yep, way off. I did not get those comments on the last, but it was fun to read some said the seat was too far forward, others too far back. I continue to slowly raise the seat more as I ride and try to feel the push. And having shorter cranks does make the fit feel much better in terms of being able to push the leg.

I also race in the aerobars when I can. If it is super windy, I sit up. If the road is real rough, I sit up. When my knee hurts, I sit up. The longer the race, the harder it is for me to stay aero, which is why I do not do long stuff.

So again, great comments, and I agree.

Dave Campbell | Facebook | @DaveECampbell | h2ofun@h2ofun.net

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Re: My testing to try and find best crank length with my Velotron [h2ofun] [ In reply to ]

Oct 31, 17 10:55

Post #339 of 1333 (10719 views)

I have been riding 150mm cranks for the last two weeks. Since I have been sick, not the best times to collect data, but what the heck.

Being a person who is tall, and ridden 200mm cranks for years, and always believing a tall person must have longer cranks, this mentally is a huge
change for me even trying. But as I was riding this morning, I have to admit, they feel just like normal. I have found, as many have stated, one can adjust fairly quickly to any length cranks.

Since I have a knee issue, one thing I am hoping is maybe by using shorter cranks, and not having to bend my knee as much, maybe I will be able to ride longer in aero before I have to sit up and stretch the knee.

At some point trying shorter cranks in real stuff is going to have to be tried. I have ridden the 175's in two races and did not find anything negative. But these were totally flat courses. So shall be interesting to try shorter stuff in the hills. Just need to find shorter cranks to try. One option I might consider is buying some adjustable cranks so I can change around. It might be having one length for a flat course, and maybe a slightly different for hills?

Fun trying to see if I can find data to support what I am riding, other than just "feel", and some expert telling me this is what crank length I should use.

Dave Campbell | Facebook | @DaveECampbell | h2ofun@h2ofun.net

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Re: My testing to try and find best crank length with my Velotron [h2ofun] [ In reply to ]

Nov 3, 17 8:06

Post #340 of 1333 (10591 views)

Just got a set of new prototype Powercranks from Frank. Much nicer design than the ones I have been using.

The new lockout feature is very cool. 3 positions. 100% unlocked cranks. Locked with 3 degrees of slip. Locked with 10 degrees of slip.
I used them this morning at 10 degrees of slip, at 150mm. I guess this show real quick if I am able to pedal of the top of the crank cycle smoothly.
I had no issues. So, not sure if the next steps will be to length the cranks and see where my pedal form fails.

Fun stuff. Sure is making the off season something I am still working on goals with.

Dave Campbell | Facebook | @DaveECampbell | h2ofun@h2ofun.net

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Re: My testing to try and find best crank length with my Velotron [h2ofun] [ In reply to ]

Nov 3, 17 8:42

Post #341 of 1333 (10557 views)

How much do those new cranks cost?

Re: My testing to try and find best crank length with my Velotron [jimatbeyond] [ In reply to ]

Nov 3, 17 9:06

Post #342 of 1333 (10524 views)

jimatbeyond wrote:

How much do those new cranks cost?

Not sure, you will have to write Frank and ask. The ones I have are very cool. Adjustable easily form like 140 to 180 or so.
The lock out is SO much easier than the old style I have.

Still waiting to hear from Frank the science behind why the lock process has 3 phases now. The totally unlocked, which is how I have used for year, is there. But the locked, which is now not 100%, but either with a 3 or 10 degree free float, is what I am asking about. Sure does give instant feedback as to if one is being a wuss in pedaling nice smooth circles!!

Like those cranks set at 150mm? Big change from the 200's I used for years.

Dave Campbell | Facebook | @DaveECampbell | h2ofun@h2ofun.net

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Lions don't lose sleep worrying about the sheep

Last edited by: h2ofun: Nov 3, 17 9:08

Re: My testing to try and find best crank length with my Velotron [h2ofun] [ In reply to ]

Nov 3, 17 9:35

Post #343 of 1333 (10481 views)

Are you saying that you received those cranks for free?

Re: My testing to try and find best crank length with my Velotron [jimatbeyond] [ In reply to ]

Nov 3, 17 9:52

Post #344 of 1333 (10457 views)

jimatbeyond wrote:

Are you saying that you received those cranks for free?

Presumably so, given he would obviously peddle (sorry) the benefits of them here.

Re: My testing to try and find best crank length with my Velotron [Kay Serrar] [ In reply to ]

Nov 3, 17 10:55

Post #345 of 1333 (10373 views)

So FD gets banned and now this one is shilling his snake oil here vicariously?

WTF is that all about.

Re: My testing to try and find best crank length with my Velotron [Andrewmc] [ In reply to ]

Nov 3, 17 12:53

Post #346 of 1333 (10279 views)

"now"?

Tech writer/support on this here site. FIST school instructor and certified bike fitter. Formerly at Diamondback Bikes, LeMond Fitness, FSA, TiCycles, etc.
Coaching and bike fit - http://source-e.net/ Cyclocross blog - https://crosssports.net/ BJJ instruction - https://ballardbjj.com/

Re: My testing to try and find best crank length with my Velotron [h2ofun] [ In reply to ]

Nov 4, 17 14:34

Post #347 of 1333 (10060 views)

h2ofun wrote:

Still waiting to hear from Frank the science

Aren't we all.

Re: My testing to try and find best crank length with my Velotron [jimatbeyond] [ In reply to ]

Nov 5, 17 10:17

Post #348 of 1333 (9956 views)

jimatbeyond wrote:

Are you saying that you received those cranks for free?

I wish. They go back when I am done testing. I am not good enough to get perks. :(

Dave Campbell | Facebook | @DaveECampbell | h2ofun@h2ofun.net

Boom Nutrition code 19F4Y3 $5 off 24 pack box | Bionic Runner | PowerCranks | Velotron | Spruzzamist

Lions don't lose sleep worrying about the sheep

Re: My testing to try and find best crank length with my Velotron [Bio_McGeek] [ In reply to ]

Nov 6, 17 15:02

Post #349 of 1333 (10772 views)

Bio_McGeek wrote:

h2ofun wrote:

Still waiting to hear from Frank the science

Aren't we all.

Are you Jim Martin?

Dave Campbell | Facebook | @DaveECampbell | h2ofun@h2ofun.net

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Re: My testing to try and find best crank length with my Velotron [jimatbeyond] [ In reply to ]

Nov 6, 17 15:04

Post #350 of 1333 (10770 views)

jimatbeyond wrote:

How much do those new cranks cost?

The advantage of these new ones is:

1. There are 3 modes with varying degrees of feedback.
2. It is easier to change between modes.
3. New users will be able to go out and do their long ride the very first day without needing to call mommy to come pick them up 10 miles from home.
4. Old users who have never done long rides on PC’s can see what happens to their form at the end of long rides (or races).
5. The feedback is more sensitive to minor technique issues.

Dave Campbell | Facebook | @DaveECampbell | h2ofun@h2ofun.net

Boom Nutrition code 19F4Y3 $5 off 24 pack box | Bionic Runner | PowerCranks | Velotron | Spruzzamist

Lions don't lose sleep worrying about the sheep

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