The Powermeter Thread

[King Boonen]

Several years ago when these were announced at Interbike I excitedly contacted Clark Foy and told him he needed to incorporate the ability to use various crank lengths including very short cranks. He apparently listened to me (although I think a few may end up going shorter than 110), and to others I suppose. Right now the ability of the PM is not much of an advance. It looks like they are planning more, according to DCrainmaker, but until they incorporate the ability to actually measure technique I think these will only constitute a small advance over ordinary PM's. I look forward to trying them.

They already measure pedal smoothness and torque effectiveness, surely that's a big step in that direction?

 

[FrankDay]

They already measure pedal smoothness and torque effectiveness, surely that's a big step in that direction?

Not really. One can have a very smooth pedal stroke with large negatives. And, just knowing the ratio of the positives to the negatives (torque effectiveness, as I understand their use of the term) tells nothing about where the negatives and positives are (necessary information if one wants to eliminate negatives), nor whether the positives are smaller than they should be at some parts of the circle (if one believes there is an optimum technique, which I do). If you don't care about technique then that data will mean nothing. If you do then that data isn't very helpful.

 

[CoachFergie]

DC Rainmaker has already got a preliminary review online for the Garmin Vector...

http://www.dcrainmaker.com/2013/08/hands-on-garmin-vector.html

 

[sciguy]

Several years ago when these were announced at Interbike I excitedly contacted Clark Foy and told him he needed to incorporate the ability to use various crank lengths including very short cranks. He apparently listened to me .

Frank,

The 110mm to 220mm range was set up by the Ant+ Alliance. I'm not certain if Clark participated in the development of the standards. Surprisingly I don't happen to see a listing for ICranks or BTS Bioengineering on the membership list. Quarq, Garmin, Rotor, Look, Saris, Pioneer and Brim Brothers made the list though. http://www.thisisant.com/business/ant-membership/current-ant-members/

Perhaps they are listed under another name that I don't know. If not, it would seem critical for them to join such a key group for power meter developers.

Hugh

 

[FrankDay]

Perhaps they are listed under another name that I don't know. If not, it would seem critical for them to join such a key group for power meter developers.

Hugh

I don't know. I will pass this info along.

 

[King Boonen]

Not really. One can have a very smooth pedal stroke with large negatives. And, just knowing the ratio of the positives to the negatives (torque effectiveness, as I understand their use of the term) tells nothing about where the negatives and positives are (necessary information if one wants to eliminate negatives), nor whether the positives are smaller than they should be at some parts of the circle (if one believes there is an optimum technique, which I do). If you don't care about technique then that data will mean nothing. If you do then that data isn't very helpful.

How do you make a power meter that measures technique then? It seems to me pedal based systems are the way forward. Does the spindle need to take the measurements? So it can measure at what point in the rotation the power is being applied?

 

[hiero2]

. . ., but until they incorporate the ability to actually measure technique I think these will only constitute a small advance over ordinary PM's. . .

Not really. One can have a very smooth pedal stroke with large negatives. And, just knowing the ratio of the positives to the negatives (torque effectiveness, as I understand their use of the term) . . .

Now, to make sure I understand what you are saying correctly, I will restate it. You are saying that "One can have a very smooth pedal stroke" but still have a large efficiency gap during part of the crankarm revolution. Presumably on the upstroke.

Wait a second. By definition, "smooth pedal stroke" means a pedal stroke that can be maintained smoothly at high rpms -- and the only way to get this is to level the muscle effort out over the whole stroke. In other words, there has to be upward effort by the leg, in order to achieve and maintain high RPM.

Saying "One can have a very smooth pedal stroke with large negatives. . . " only gives me more reason to be skeptical of other conclusions you present.

 

[King Boonen]

Now, to make sure I understand what you are saying correctly, I will restate it. You are saying that "One can have a very smooth pedal stroke" but still have a large efficiency gap during part of the crankarm revolution. Presumably on the upstroke.

Wait a second. By definition, "smooth pedal stroke" means a pedal stroke that can be maintained smoothly at high rpms -- and the only way to get this is to level the muscle effort out over the whole stroke. In other words, there has to be upward effort by the leg, in order to achieve and maintain high RPM.

Saying "One can have a very smooth pedal stroke with large negatives. . . " only gives me more reason to be skeptical of other conclusions you present.

I can see how it's possible, it's just balancing forces afterall.

I'm assuming a negative on the upstroke is caused by downward pressure/no upward pull, if this change is consistent with the forces applied by the opposite leg then the movement would still be smooth, just not as efficient.

 

[FrankDay]

How do you make a power meter that measures technique then? It seems to me pedal based systems are the way forward. Does the spindle need to take the measurements? So it can measure at what point in the rotation the power is being applied?

Depending upon the geometry of the pedal and crank, any given pedal force in any given direction can only result in one "geometry" of stress in the pedal spindle/crank arm. If one measures enough of those stresses in the crank arm one can "reverse engineer" what the stresses are on the pedal. They do not need to be measured directly.

 

[FrankDay]

Now, to make sure I understand what you are saying correctly, I will restate it. You are saying that "One can have a very smooth pedal stroke" but still have a large efficiency gap during part of the crankarm revolution. Presumably on the upstroke.

Yes, but I am using the current definition of pedaling smoothness as it affects the bike as a whole, i.e., both cranks acting together. This is what spinscan measures. Using this definition pedaling smoothness is simply the ratio of the average crank torque around the circle divided by the maximum crank torque seen. Since the two pedals are combined in this calculation high negatives subtract from the high maximums making the maximum, for the purpose of calculation, lower and resulting in a "high" smoothness number.

Wait a second. By definition, "smooth pedal stroke" means a pedal stroke that can be maintained smoothly at high rpms -- and the only way to get this is to level the muscle effort out over the whole stroke. In other words, there has to be upward effort by the leg, in order to achieve and maintain high RPM.

While I would tend to agree with you that smoothness should be what you say, smoothness is generally defined as noted above, the ratio of average torque to maximum torque partly, because it is essentially impossible to measure muscle effort around the circle because we live in a gravitational field.

Saying "One can have a very smooth pedal stroke with large negatives. . . " only gives me more reason to be skeptical of other conclusions you present.

Well, one can using the currently generally accepted definitions. I personally think a better definition would be some sort of measure of circularity. I go into this a little bit when I am discussing what it means to "pedal in circles" here

 

[Boeing]

Question: Do power meters measure how powerful you are?

 

[CoachFergie]

Yes, but I am using the current definition of pedaling smoothness as it affects the bike as a whole, i.e., both cranks acting together.

Frank, this is a thread about racing and training with a meter that measures power. There is a thread devoted to pedalling technique where you can continue trying to convince us that there is any importance to training pedalling technique.

If people look back in the previous posts that you haven't tried to hi-jack you can see that the quest for more power, more power to weight, more power to frontal area, more power for a specific event, more power for different disciplines in cycling, better management of power in a race, in a training block and over a season actually has an impact on performance we can see why discussing the equipment, recording and analyse of power meter data is an important part of the cycling performance process.

 

[FrankDay]

Frank, this is a thread about racing and training with a meter that measures power. There is a thread devoted to pedalling technique where you can continue trying to convince us that there is any importance to training pedalling technique.

If people look back in the previous posts that you haven't tried to hi-jack you can see that the quest for more power, more power to weight, more power to frontal area, more power for a specific event, more power for different disciplines in cycling, better management of power in a race, in a training block and over a season actually has an impact on performance we can see why discussing the equipment, recording and analyse of power meter data is an important part of the cycling performance process.

LOL. Perhaps you haven't noticed that this thread has evolved because of the recent availability of a power meter that does more than give a simple power number and that some here might want to discuss what that data means and how one might want to use it. It must be quite an issue for you that power generation and technique might actually be connected. The fact that there are two separate threads on power meters and technique is a purely artificial separation dictated by those with a "they are unrelated" bias. The Vector pedals and iCranks (and others) are about to smash such narrow thinking, me thinks. We will see.

 

[CoachFergie]

If Power Meters evolved to make Espresso as well I don't think this is the thread to discuss the effects of caffeine on performance.

 

[CoachFergie]

Two excellent reviews on power meters.

A 2nd review of the Garmin Vector...

http://www.bikeradar.com/road/gear/...uct/review-garmin-vector-power-meter-14-47478

And Alex Simmons has done an outstanding review of all the current, not so current and some of the potential meters coming to market.

http://alex-cycle.blogspot.co.nz/2013/08/which-power-meter.html

 

[CoachFergie]

Ray Maker does a summary of the updates and new power meter options from Eurobike...

New Power 2 Max options

Chargeable crank SRM and PC8

Brim Brothers delayed again

http://www.dcrainmaker.com/2013/08/eurobike-power-roundup.html

 

[CoachFergie]

For the Triathlete considering riding and racing with a power meter...

http://www.endurancesport.co.nz/story.cfm?id=104908

 

[CoachFergie]

The 2013 Power Meter Buyers Guide. By Ray Maker.

http://www.dcrainmaker.com/2013/09/power-buyers-edition.html

 

[Boeing]

so essentially that what coach fergie is saying is if you have power you are strong and if you are strong your are fast.

 

[FrankDay]

so essentially that what coach fergie is saying is if you have power you are strong and if you are strong your are fast.

Just having power is enough? Wow, where do I buy?

 

[CoachFergie]

If people don't appreciate Frank trolling this thread make sure you report his message!

 

[Retro Trev]

Although I do not think here is anything in such pedalling techniques as pulling up pushing over the top and scraping back etc etc. I do think it is wrong to accuse people you do not agree with you of trolling.

This is not the only forum where anyone who has an opinion which is not agreed with by the majority or those who think they are the 'experts' seem to think they can call anyone who dares to state an opposing view a troll.

Reporting people for trolling because you do not agree with them is in my opinion the action of a troll.

 

[Retro Trev]

I have tested Garmin Vector which is of interest to me because i have a severe imbalance 60 / 40 at some powers and cadences.

Can Vector tell me if I am applying any reverse force on the upstroke?

My pedalling technique has no pull up, no pushing over the top, or scraping back but I have a feeling one of my legs may be lazy or slow and applies some counterforce on the upstroke - is there a way of measuring this?

 

[CoachFergie]

Reporting people for trolling because you do not agree with them is in my opinion the action of a troll.

waa waa waa and calling the person who calls out the action of a troll a troll is in my opinion acting like a troll.

Frank has continually put up strawman arguments against power meters the whole way through the argument. He has been warned about doing this and was banned for a week. He is clearly a troll. My 1% of noise in pointing people towards the correct course of action should be balanced against the 99% of on topic discussion about riding and racing with a power meter.

 

[CoachFergie]

I have tested Garmin Vector which is of interest to me because i have a severe imbalance 60 / 40 at some powers and cadences.

Can Vector tell me if I am applying any reverse force on the upstroke?

My pedalling technique has no pull up, no pushing over the top, or scraping back but I have a feeling one of my legs may be lazy or slow and applies some counterforce on the upstroke - is there a way of measuring this?

The Garmin head unit does not measure force vectors (yes how ironic) from the pedals yet. The only meters that do are the Pioneer and the Rotor models. One would expect they would measure the force on the upstroke.

Why do you think there is an imbalance and under what conditions does it approach 60 / 40?

And going off topic why do you think measuring force vectors around the pedal revolution will offer a solution other than spending time trying to achieve 50 / 50?