Well they fool some powermeter...

Yeah, they do .. but not the time .. ;-)

---

*
___/\___/\___/\___ the s u r f b o a r d of the K u r p f a l z is the r o a d b i k e .. oSo >>

Dan,
Sorry if I have missed some important stuff in this thread, but your post has got me thinking Dan.
Sorry if I am about to butcher torque/force etc.
But in the instance of short cranks. I find the 155s I have feel like I have to generate too much force in too short a time for my long long legs (37inch inseam) to tolerate.
I find I have a limitation on rpm in aero position. Sat up I’m fine. 100 on the turbo is no problem.
To counteract this, would a longer crank allow me to generate more torque to compensate for the lack of spin?

well, theoretically, you have this interplay: yes, you need to generate (a little bit) more torque with a shorter crank. and, not only is the lever (the crankarm) shorter, torque is force x that lever, and it's that x the cosine of the angle created between the diagonal perpendicular to the force and the line from the fulcrum of that angle (the BB) and the place on the pedal circle where you are at any moment - which is to say that there's only one perfect place on the pedal circle and you move away from that place incrementally more quickly on a smaller pedal cycle circumference, if time is the measure (just, i'm a little fuzzy on this part, i'd have to think this through a bit).

countering that is another mechanical element, which is your body. on the bicycle you have two machines at work, that interplay. your bicycle is a machine, with all its physical features. and your body is a machine, with its physical features. you have force applied at the end of a lever, right? but, what am i talking about? in the paragraph above it's the crank, and the BB is the fulcrum, and the crankarm is the lever. but i might also be talking about your hip as the fulcrum and the femur as the lever. this is where you gain back that mechanical disadvantage of the shorter crankarm. you begin to push down with a new mechanical advantage granted you by the shorter crank, assuming your retain your same aspect into the wind (identical armrest elevation drop from saddle to armrest pads).

here's something i'm pretty sure nobody offers you, but that i think might be fun. and i'm not offering it either, but bear with me. I have, what, 4 (i think) fit bikes in my studio: a GURU, an exit cycling, a purely custom, and another purely custom that just showed up and is still in the crate. they all have adjustable cranks. they all have smart resistance units. so i could put you on any one of these, in your position, and put you through a performance test, retaining your position exactly, just with different crankarm lengths. and you could see right there, in the course of, say, an hour, which crankarm is best for you.

---

Dan Empfield
aka Slowman

Thank you for your reply Dan.
Ok, so let’s add this into the mix.
I am happy putting out power on the 155s on the turbo, if anything it’s higher.
But on the road I feel it’s too fast in aero.
I have 2 chainsets, 155 snd 165.
Any logic in training 155 on the turbo and riding 155 on the road? 155 on the turbo to improve force generation and then 165 on the road to make better use of this force?

Funny you should say that about the rig, me and a friend who is looking into bikefit and is an engineer are planning on building one with adjustable cranks

Dude, if you have a 37" inseam then perhaps you should be on the 165's. In comparison to your legs, those are the short cranks everyone talks about. You may have gone too far for your size, I certainly would go to 165's with the 7" longer leg you have than me. I have 30" inseam and I ride 155's...

Yes I think I maybe went a little TOO short!

The only problem is that it's reasonably likely that there is a period of adaptation to a new position/crank length. That period could be on the order of a month so a quick 5min test doesn't necessarily provide information on an optimal length.

Not true, at least in terms of maximal muscle power.

But how often are you putting out maximal muscle power while seated? Is the optimal setup for maximal muscle power also optimal for riding at 80-100% of FTP?

The point is that our neuromuscular system is quite flexible, and readily adapts to new tasks. There is no reason to believe that the intensity of the exercise makes any difference in this regard (and in fact, at the level of the individual motor unit, all exercise is near-maximal, even when you are just cruising along).

If you start mentioning Frank Day, I'm going to assume waterboy hacked your admin account...

---

http://bikeblather.blogspot.com/

I guess your new nickname is "Red" then :-)

---

http://bikeblather.blogspot.com/

Boom. End of thread. Once again Alex distills it all down for us.

---

http://bikeblather.blogspot.com/

it didn't end it for me. i guess you didn't see my reply to that post.

---

Dan Empfield
aka Slowman

It should have. And I did.

Between Alex and Andy's replies, you should have all you need to know.

---

http://bikeblather.blogspot.com/

i'm sorry. i didn't (and don't) see alex's reply. or andy's reply that spoke to my question.

---

Dan Empfield
aka Slowman

This thread is a train wreck.

Andrew Coggan wrote:

This thread is a train wreck.

i don't see what's train wrecky. what i see in the thread is that a few people have raised this question. me, i don't know. i'm just asking.


alex wrote two things: "metabolically, knowing your torque or cadence is not particularly helpful, while knowing power most definitely is," along with, "far better to focus on effort level and choose a gear appropriate for the situation."


to me, just reading those two statements, they don't square for me. if you choose the appropriate gear, you're choosing on what basis? what makes it "appropriate"? is the thesis here that you don't need to pay any attention to either torque or cadence? i very strongly suspect that the great majority of folks who earn their living from cycling, as cyclists - or coaches, etc. - would not agree that cadence is not to be considered.


i don't want to put words on anyone's mouth, but i can only read your words, not your mind.

---

Dan Empfield
aka Slowman

In your OP, you talked about "riding to torque" and asked "anything out there on that?"

You had an exercise physiologist, who you called out by name in your thread title, and a well-respected cycling coach both explain why it's, as RChung commented, a "red herring".

So yeah...asked and answered

---

http://bikeblather.blogspot.com/

let me rephrase. why is it a worthless notion?

i'm not an expert in very many things, but, in such case i'm asking a question that's in my wheelhouse, if you ever catch me pulling rank, that is, saying that a notion is worthless and refusing to explain why, or to offer evidence, historical practice, reasoning, please call me out on it. you'd be doing me a favor.

---

Dan Empfield
aka Slowman

http://forum.slowtwitch.com/...ost=6591363#p6591363

"Slower pedaling -> higher force for same power -> GREATER recruitment of type II motor units.

OTOH, faster pedaling -> lower force threshold for recruitment of any given motor unit -> greater recruitment of type II motor units.

IOW, the effects of cadence (at least at the extremes) on motor unit recruitment are more complex than you seem to be assuming. "

---

http://bikeblather.blogspot.com/

you're writing me back (in part) what i wrote. slower pedaling = more type II fiber recruitment. which could be detrimental. i'm asking a pretty basic question, and i'm really not getting an answer. power = torque x cadence. we look at cadence. very hard. have been for generations. we've never been able to look at torque. until this generation. so, if cadence is that important, why is the other metric not important?

specifically, if the point of cadence is, really, to pedal with the optimal torque, might it be interesting to look at torque? has anyone ever done it?

what i'm variously getting is - parsed - none of it is important to look at (cadence or torque), or, it's more complicated than that. which, really, is not an answer.

i don't mind if the answer is just not known (or if it's never been considered; or already tried and proved to be a false lead). i have no problem just hearing "i don't know." i say it all the time, in fields in which i'm considered an expert, because there's either not known or, if it is, i don't know it.

i have only a very casual interest in this. but you keep saying i've gotten my answer and i really haven't. i've gotten gobbledygook, and i've had rank pulled, but an answer is something i've certainly not gotten.

that said, while i found it an interesting thought experiment, it's not important to me. nobody should be more ardent in crafting an answer than i am ardent in hearing it. i withdraw the question.

---

Dan Empfield
aka Slowman

An exercise physiologist, a cycling coach, and an engineer walk into a bar, and . . . ?

I’ve only gotten to the end of page 1 (so far...), but there is something in knowing torque (if you also know power & cadence).
By plotting the relationship between all three you will find a point (relative to cadence) where power & torque cross over, this point will most likely be your most efficient cadence relative to your cardiovascular aerobic fitness. It could be useful to know this...