Chinese gear that measure the power output of both legs in watts?

[genealogyxie]

Are there any Chinese cycle computers (similar to the Garmin Edge 1040 Solar) that measure the rider's total power output (in watts) for each leg? So I assume this would also require at least two strain gauges or other type of force sensor on a special crankset. Do riders actually use the cycling computers during races as well, or would that just add in unnecessary weight to the bike?

[PLA]

The power meter (single side or dual side) measures the power, the computer just displays the results. Racers usually use the smaller computer like the 840 or Bolt V2. Igpsport 630 is a popular Chinese computer. Crank or portal meters come in single or dual versions. A popular Chinese power meter is the spider type Magene P505, which measures both sides.

[TribesMan]

Spider based power meters are really not good at estimating left/right balance.
They can't differentiate between power the left side pulling and right side pushing, and vice versa.

I tested this several times, for instance you can unclip your left leg and cycle only with your right leg.
The L/R balance should be 0% / 100% (and my Favero Assioma pedals confirm that)... but the spider based power meter will estimate the L/R power based on how much pulling up you do with the right leg, and assign that to left side power, and pushing down with the right leg will be assigned to right side power. So it is basically useless.

Only crank based or pedal based power meter can accurately measure L/R balance.

[kbernstein]

Technically yes, spiders can't tell left pulling from right pushing, but it really shouldn't matter in the real world. Most people don't pull at ALL, so it's safe to assume all the power comes from pushing the other side. So unless you only have one leg, then spiders should have a pretty good L/R accuracy.
Unless of course you still believe in the "round pedaling" efficiency bullshit and make a conscious effort to pull

[TribesMan]

It matters quite a lot.

In my case my left leg was always "a bit lazy".
When I try to do single leg drills, right leg is very smooth, but left one feels like pedaling squares.

On my Assiomas measured L/R balance is 45/55 (also confirmed on friends Garmin Vectors).
But spider based power meter reports L/R balance at 53/47.
I assume that because my left leg does almost no pulling, and right one does some, the interpretation is completely wrong in the end.

So yeah, L/R estimation on anything that is not pedal or crank based, is completely useless.

[PLA]

For any normal case, a spider is fine. If one leg is pedalling squares and the other circles, then you got deeper issues than your power meter.

[TribesMan]

My point is, spider based power meter is not a good tool if you want to observe your L/R balance.
It measures total power just fine and it's a great tool for training, but fails miserably when it comes to L/R balance.

Also, no matter what I tried, I could not get my L/R balance closer to 50/50.
I spent a few winters doing single leg drills, single leg weight training and so on... almost no change.
The best I've seen was 46/54... ¯\_(ツ)_/¯

[kbernstein]

Are you making a conscious effort to pull on the return? My point was that you shouldn't try doing any of that. It's okay to have a small unbalance (although 45/55 is pretty high, do you have a condition perhaps?) and specifically training to "correct" those is kind of a waste of time. It's just an interesting stat and of course spiders can't differentiate left pulling from right pushing but it shouldn't matter much as you shouldn't be pulling

[TribesMan]

Its not so much about "pulling" as it is just unloading the pedal on the way up.
I find it quite natural on the right side, I don't have to even think about it.
Sometimes when I ride a bike with flat pedals I notice that my right leg gets a bit of "air time" on the upstroke.
But the left leg was never like that. No injuries, no conditions, same leg length... its just "lazy".

[genealogyxie]

Its not so much about "pulling" as it is just unloading the pedal on the way up.

Yeah, that definitely makes sense. Maybe some athletes might think this newfangled tech is useless, but didn't some people think that the MP3/iPod players were going to be just a fad?