power meters

[jamma]

Is there any difference from a dual sided one and a left crank only apart from the obivious reasons i.e: 1-2% discrepency, left crank power meter doubles reading for right crank


And before anyone starts with you don't need one or why are you buying one. I am not just wanting to see what other reasons behind both powermeters apart from the obivious ones.

 

[T.M.H.N.E.T]

Cost and compatibility

 

[MistaDee]

A single-sided power meter measures the power of only one leg, usually the left. To provide your complete power, it doubles the power on the measured side. This assumes perfect symmetry, but most people are not perfectly balanced and consistent.

 

[Cuchilo]

I've been looking into them lately and it seems to me that the people that use them like the pedal based systems and the people that make them like the other systems . Having spoken to quite a few people i have come to the conclusion that they are all crap , go wrong , give bad data and are fiddly .

 

[T.M.H.N.E.T]

A single-sided power meter measures the power of only one leg, usually the left. To provide your complete power, it doubles the power on the measured side. This assumes perfect symmetry, but most people are not perfectly balanced and consistent.

People with single side PM's clearly aren't worried if their right leg is 5% weaker than their left. They want accurate repeatable data in an easy to use package.

I've been looking into them lately and it seems to me that the people that use them like the pedal based systems and the people that make them like the other systems . Having spoken to quite a few people i have come to the conclusion that they are all crap , go wrong , give bad data and are fiddly .

But having never used one of course, your conclusion would be very much incorrect.

 

[si_c]

The differences between power meters are largely irrelevant, unless you want to measure the difference between left/right leg power.

If you are using a left side power meter it will be inaccurate because your left/right leg imbalance, in practice this doesn't matter as you are using it for consistency purposes so you are not comparing yourself to others, just to your self, so as long as you keep the same power meter it will give you useful information.

Comparison between units which only measure the left leg power and those which measure the power in a different location within the drivetrain (pedal/rear hub) show the differences to be small. DC rainmaker has a good breakdown of all the different power meters, and is pretty much the go to source for information.

 

[T.M.H.N.E.T]

The differences between power meters are largely irrelevant, unless you want to measure the difference between left/right leg power.

If you are using a left side power meter it will be inaccurate because your left/right leg imbalance, in practice this doesn't matter as you are using it for consistency purposes so you are not comparing yourself to others, just to your self, so as long as you keep the same power meter it will give you useful information.

Comparison between units which only measure the left leg power and those which measure the power in a different location within the drivetrain (pedal/rear hub) show the differences to be small. DC rainmaker has a good breakdown of all the different power meters, and is pretty much the go to source for information.

Lets not overstate the imbalance thing. If a double sided pm reveals that you have an imbalance, it's highly likely that you had the same imbalance long before getting the PM.

So if you'd not bought the pm or bought a single sided pm instead, you still wouldn't be aware you had an imbalance (cos it's such a big deal)

 

[si_c]

Lets not overstate the imbalance thing. If a double sided pm reveals that you have an imbalance, it's highly likely that you had the same imbalance long before getting the PM.

So if you'd not bought the pm or bought a single sided pm instead, you still wouldn't be aware you had an imbalance (cos it's such a big deal)

That was pretty much what I was trying to say in a roundabout way. Ignore the imbalance it's irrelevant, get the PM that suits you and then compare the power only with yourself. It's fairly safe to say that if your left leg is putting out more power than before, your right probably is too.

 

[jamma]

So in theory which either pm you buy the zones for training are going to be the same anyway cause the spefic to you only.

 

[T.M.H.N.E.T]

Yes

 

[Cuchilo]

So in theory which either pm you buy the zones for training are going to be the same anyway cause the spefic to you only.

Now i have a bit more time to answer than this morning .
Apparently the more accurate power meter would be a crank based one or even better a bottom bracket based one . Pedal based meters are taking readings from about seven different sensors but can only read in one direction so are not getting a true reading where as a crank would take all the power transered through the pedal into one direction before it takes a reading . I think

 

[MistaDee]

The biggest impacting factor of power meters above all is knowledge, you can have the most advanced and accurate power meter available & unless you understand the data it provides along with what training is required to get desired improvements you are wasting money unless you are going to employ a coach to go through the data for you.

There are a hell of a lot of power meter users pulling data for Stava that know little about data or training.
Invest and learn about training with a power meter then you will know what system you want to utilize and the limitation of it.

 

[si_c]

Now i have a bit more time to answer than this morning .
Apparently the more accurate power meter would be a crank based one or even better a bottom bracket based one . Pedal based meters are taking readings from about seven different sensors but can only read in one direction so are not getting a true reading where as a crank would take all the power transered through the pedal into one direction before it takes a reading . I think

They all pretty much fall within each others margin of error, so does it really matter at that point (I'm simplifying a bit ofc).

 

[Cuchilo]

They all pretty much fall within each others margin of error, so does it really matter at that point (I'm simplifying a bit ofc).

To start with maybe but over time the pedal based system has more potential to wear .

 

[S-Express]

Now i have a bit more time to answer than this morning .
Apparently the more accurate power meter would be a crank based one or even better a bottom bracket based one . Pedal based meters are taking readings from about seven different sensors but can only read in one direction so are not getting a true reading where as a crank would take all the power transered through the pedal into one direction before it takes a reading . I think

I think that over-states the effect of pulling up (if that's what you meant). It accounts for very little of the force through the pedals.

The main requirement for a commercial power meter is consistency, if not accuracy. In that sense, it doesn't really matter where the power is measured. Pedal-based, crank arm-based or crank spider-based meters will probably all give you different readings anyway, and a Powertap hub will probably give you another different reading, although it could be argued that the hub reading may be the most useful, as it is effectively towards the end of the transmission process, rather than near the start of it. Think of an engine's power being measured at the crankshaft, compared to its power measured at the wheels.

If you want accuracy, then lab-based test equipment is the way forward.