powertraining aids

[lowracer]

appologies for starting another thread, but the other one is going from bad to worse to slightly better

 

Supposedly chain-drive bikes is 98.5 percent efficient, although efficiency does tend to drop when chains are exposed to dirt and the elements

 

here is an example of such a study

http://www.jhu.edu/news_info/news/home99/aug99/bike.html

 

With the worst of the bikes, (assume rusted chain, no lubrication, etc) the efficiency dropped to 81%.

 

I'll be quite safe to say that RH's bike should be reasonably squeaky clean, but if we go for a 'really dirty bike for RH" , i'm quite sure you'll still get 95% efficiency at least, at the end of a long day's ride.

(please note : lubrication does not make that big a difference, though dust picked up might)

 

so if one piece of equipment measures at the crank, and another at the hub, there should be at most 5% diffence between the 2 measurements.

so if one measures 1500 watt at the crank, the other should be at least 1425 watt at the hub, and the chain measure should be somewhere in between.

 

ok real life question : what difference are you looking at between the measurements given by different powermeters.

 

[NotSoBigBen]

OK so let me start with a standard disclaimer "I'm just a layman so any comments made are just my own personal thinking and should not be followed by anyone who hasn't had medical (or psychiatric) advice"

 

So does it matter? Probably not unless you want to compare your output with someone else's!

 

My thinking is that if you are using it as a training aid then as long as it's readings are consistent then you will know if you are improving or reaching your previous levels etc.

 

Should you want to compare with someone else's then use theirs!

 

I'm ready for any flames!

 

[BikeMax]

 

The difference in the location of the strain guages in an SRM Vs a PT should result in a difference of around 2% - the SRM being the higher of the 2.

 

In real terms the difference is insignificant and within or around the accuracy parameters of both devices.

 

BB - you are correct in one sense but I can tell you that the comparison of rider data is a very valuable analysis tool in giving a rider goals and also measuring economy in a race situation, and from this perspective it is important to have an accurate device.

 

 

 

BikeMax2007-09-13 06:54:57

[The Saint]

Well If I had to hazard a guess the best power training aids I can think of would be "Legs" the rest is just science.

[bruce]

The difference in the location of the strain guages in an SRM Vs a PT should result in a difference of around 2% - the SRM being the higher of the 2.

In real terms the difference is insignificant and within or around the accuracy parameters of both devices.

BB - you are correct in one sense but I can tell you that the comparison of rider data is a very valuable analysis tool in giving a rider goals and also measuring economy in a race situation' date=' and from this perspective it is important to have an accurate device.


[/quote']

 

I think the caveat to this statement is the degree of accuracy to which two riders are compared.  If one rider had a threshold power of say 5.1w/kg, and another 5.08w/kg, for all intents and purposes they are the same.

[bruce]

Well If I had to hazard a guess the best power training aids I can think of would be "Legs" the rest is just science.

 

I dunno, there is also a good book by Allen & Coggan - bit of a study aid I guess.  There are also some very good aids on bikemaxpower.com and google wattage group.

[bruce]

appologies for starting another thread' date=' but the other one is going from bad to worse to slightly better

 

Supposedly chain-drive bikes is 98.5 percent efficient, although efficiency does tend to drop when chains are exposed to dirt and the elements

 

here is an example of such a study

http://www.jhu.edu/news_info/news/home99/aug99/bike.html

 

With the worst of the bikes, (assume rusted chain, no lubrication, etc) the efficiency dropped to 81%.

 

I'll be quite safe to say that RH's bike should be reasonably squeaky clean, but if we go for a 'really dirty bike for RH" , i'm quite sure you'll still get 95% efficiency at least, at the end of a long day's ride.

(please note : lubrication does not make that big a difference, though dust picked up might)

 

so if one piece of equipment measures at the crank, and another at the hub, there should be at most 5% diffence between the 2 measurements.

so if one measures 1500 watt at the crank, the other should be at least 1425 watt at the hub, and the chain measure should be somewhere in between.

 

ok real life question : what difference are you looking at between the measurements given by different powermeters.

 

[/quote']

 

This is a very good question.  Apparently some top level riders have a variance of less than 10% power output between off-season and peak.

 

Realistically, we can expect a variance in performance of 1%-2% in a rider on any given day (based on the assumption that the ride is not injured, dehydrated, etc etc) due to motivation etc.

 

I would take a guess that differences of around 5% are statistically significant.

 

The width of the racing categories in Coggan's power profile for 60min power are around 10% between top rider in category and bottom rider.

[AndreZA]

When I read the heading I thought it was something you got when you used your mates Power tap without protection.

 

[Barend de Arend]

 

so if one piece of equipment measures at the crank' date=' and another at the hub, there should be at most 5% diffence between the 2 measurements.

so if one measures 1500 watt at the crank, the other should be at least 1425 watt at the hub, and the chain measure should be somewhere in between.

 

ok real life question : what difference are you looking at between the measurements given by different powermeters.

 

[/quote']

 

The difference in power meters will also be exagerated on very short bursts of power.  Measurements of peak power for less than 5 seconds will vary wildly.  Measurements of sustained power will be much closer.

 

One reason is that in 1 second, you've only done 2 to 4 pedal strokes (two pedal revolutions), so the power will be very variable.

 

Another is that not all power meters measure the same number of samples per second, and some display a rolling average, some a peak, and some a random sample.

 

On sustained efforts, expect 2%.

 

 

[Guest Big H]

Well if I was one of those VETS with a LOT of munny I would get the one that measure the most volts or is it watts?????? The brag factor.... that is all this really is about.... whilst drinking a cup of coffee or standing in the starting blocks will be the best benefit (without lying.... cyclists are worse than fishermen!!!!!) own testosterone inflated VET mind!!!!!!! What does it really matter...... you use the same volts generator and the results will thus be the same inaccurate standard!!!!!!!!

[fandacious]

Well if I was one of those VETS with a LOT of munny I would get the one that measure the most volts or is it watts?????? The brag factor.... that is all this really is about.... whilst drinking a cup of coffee or standing in the starting blocks will be the best benefit (without lying.... cyclists are worse than fishermen!!!!!) own testosterone inflated VET mind!!!!!!! What does it really matter...... you use the same volts generator and the results will thus be the same inaccurate standard!!!!!!!!

 

I thought this stirrer had left. I much preffered Hendrik Petoors. Anyways I'm sure thats why RH has his power meter. So he can brag over coffee with his friends.

 

Oom - we know you're more intelligent than that so why make silly comments? Just because you dont believe in it/dont like it/dont have one, doesnt make you better than every one else, or give you the right to demean those who do...

[Guest Big H]

Het jy een en is dit hoekom jy suurtiet is????????

[fandacious]

Suurtiet? Wie se eks siertiet... jy's die een wat vir my suurtiet klink? I'd really love to have one as it would definitely help me monitor my training and accurately target the areas I can improve on.

[Guest Big H]

Eddie Merxks became the champion he was WITHOUT any fancy attachments like HRM and Voltage Generators. You do not need it and youcould also become a fit and strong cyclists without these by applying well treid norms of training,

[fandacious]

Eddie Merxks became the champion he was WITHOUT any fancy attachments like HRM and Voltage Generators. You do not need it and youcould also become a fit and strong cyclists without these by applying well treid norms of training' date='[/quote']

 

And Contador became champion at his young age by using all those aids....

[ewep]

Oom H, goeie redenasie, MAAR, hoekom werk oom dan nie met 'n abakus en passer om die paaie uit te l? nie?  En ja, ek het nou 'n Polar Power ma-goefter en dis 'n excellent training tool (net 'n tool)