Your right leg is stronger than your left.

Stages just doubles your left leg's power.

If I could do 300 watts for an hour, (knowing my power balance) my left leg is only responsible for 135 while the right leg is doing 165.

A Stages would have me at 270 for the hour while a Powertap (or anything measuring total input of both legs) would be ~300.

If that's the case, wouldn't my left leg "come around" with simply trying harder to get my watts up or will my right leg simply continue to stay X% stronger?

I don't know. I'm not aware of too much research yet in that area.

My n=1 shows that I am constantly at a ~45/55 L/R balance at race pace for the last couple seasons. Even if power is getting better or worse. Easier rides it's closer to even. Maybe people with greater knowledge of pedaling technique could chime in, but again, I don't think definitive knowledge has been established.

Seriously though, congratulations on making some good gains in speed.

Not sure about you, but when I increase my effort to raise my power output, it's usually with both legs. If you made a conscious effort to work your left leg harder, I suppose it would eventually "come around," but I bet they never get 100% equal.

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''The enemy isn't conservatism. The enemy isn't liberalism. The enemy is bulls**t.''

—Lars-Erik Nelson

Maybe you power is lower, but other things changed. Maybe you lost weight, maybe you are more aerodynamic, maybe you are staying in an aero position more, maybe more aerodynamic clothing, maybe better tires, maybe better tires and pressure? At the very least you say you changed rear wheels.

Yes, Stages always lower than my two Powertaps going by RPE. You're probably rigtht leg dominant, so why worry about it? Just compare like with like. Bottom line is not how much power you're producing it's how fast you're going.

Also insert sarcastic statement about it not mattering as long as power meter is consistent with itself.

Well first off if you upgraded your bike "Big Time" you won't require the same level of fitness to go faster so the numbers won't necessarily need to be the same for faster results. Secondly a difference of 10w @ what FTP? If it's 150W that is a high % difference but if it's at 320W then obviously it's less in the way of a % difference. Last but not least let the course times be the measurement not the reading of your power meter. Ultimately you want to be faster and get better results not have a number to brag about. Sure it is great for training but you changed a variable and that means that you'll have to reset so the data has the same source which in this case is a new power meter.

Had you kept the other wheel and got the variance you could adjust numbers for this but it doesn't sound like you held onto it. Don't over think it and continue to achieve more and next year you'll have better historical data to utilize.

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"Train so you have no regrets @ the finish line"

   My experience with 2 Stages PMs (one on Tri bike and one on road bike bike), compared to rides of anywhere from an hour to 2 1/2 hours on my Computrainer (CT) is that my average power is within a couple of watts between the Stages and CT. My leg power is not 50/50 either, I do more work with my right leg and can see splits of 45/55. But, that depends upon my cadence and workout, I've seen times when my left leg produces more power.

The Stages only records left leg power - including push down, push over the top, pull through the bottom and pull up. The CT records power based upon crank arm position and so right leg pull up is added to left leg push down. So it isn't as simple as one leg being more powerful, it is also how much work each leg does throughout the full circle and you'd need something like a Vector to measure this, crank based systems can't.

Then there is drive train loss. Theoretically a Wheel based system should show lower power than a crank or pedal based system.

I've noticed a real large difference between speed and power on my road bike versus my Tri bike. When I look at something like a 50 Km loop, I can be faster on my Tri bike with 15% or more fewer watts over the same loop compared to my Road bike. You mention a BIG bike upgrade.

Finally, can you put your PT on your new bike, just to test out the average over a couple of different courses?

While I've been disappointed with the average power on some of my rides, I've been happy with the average speed / time.

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BC Don
Pain is temporary, not giving it your all lasts all Winter.

While that is true for training if you are trying to do race modeling it can have a pretty big impact on the accuracy of the results. We have seen a lot of this lately. In theory if everything was equal stages, garmin s etc should read a bit higher than power tap. But due to leg discrepancies you can see these swings. You could counter balance it for modeling by saying you have a negitve mech loss (mech gain :)) But you would need to do some race pace efforts with what you believe to be a reliable full system (non single leg only) power meter.

For training and even pacing you are probably good to go but if you want to really start digging into advanced planning you may want to do a few tests.

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Founder: BestBikeSplit
Amazonian

As a Stages owner, this is the biggest problem with the product in my opinion. You can't compare apples-to-apples in terms of long-term gains.

If you switch from Quarq to PT to P2M to SRM, you are always getting a complete picture of your power numbers. With Stages there is always that glaring blank space of "wtf is my right leg actually doing?"

I think the biggest issue is not for people who know they are 55/45 across the spectrum, but for those who have a balance that changes with intensity. I'm glad I have my Stages, but I see it as a better measurement than heart rate, but not as good as a "real" power meter.

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/kj

http://kjmcawesome.tumblr.com/

I'll try to hit everything but I'm sure I'll miss some:

1) Yes, upgraded my bike and wheels to more aerodynamic stuff. Based on BBS, I'd be gaining something like 5 minutes over an Ironman at the same watts. On my local 100 mile ride (alone), I'm pushing 10 less watts and going 1mph faster. The numbers don't add up unless my meter is low.

2) No, I don't have the PT anymore. If I did, I would have tested a long time ago to see what, if any, difference there was.

3) It does and doesn't matter for training and racing. You're right, as long as the Stages is consistently accurate, I know what to push on race day and I shouldn't have a problem. I've already done this throughout the year. However, if I'm targeting a big goal for my A race and know I need to push X watts to hit said numbers, having low numbers will skew my targets and I need to figure that out now.

Probably missed a few.

Do you have a sustained climb you can do not in aero? I may be looking at your data already, but can at least see if it's in the ball park.

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Founder: BestBikeSplit
Amazonian

Yeah, tons! Gotta live Los Angeles.

I typically don't swap my PM from my TT bike to my road bike but I'm covering 5 mile and 9 mile climbs significantly faster at same rpe and hr as last year.

I'd wager a guess that you haven't fully absorbed the reviews of stages and the potential issues. With left leg only, there is no way to compare power output to other devices unless both are on the bike at the same time.

So, your fitness could be up or down compared to last year, there is no real way to know without some form of independent testing. Can you go back to your old bike setup and compare times on know courses?

When I went from PT to Stages I kept both on the bike for about a month. Reviewed my rides and decided they were close enough to not bother me. Used the stages for the last 2 years and am still very happy with it.

I have a Powertap you could borrow to check (11sp cassette installed.) I'm in Santa Monica.

Thanks for your post and for verifying the same experience I am having with Stages...

I suspected my power numbers were low when comparing TT and FTP test results with riding buddy (similar weight and fitness but he uses a Powertap).

Last night, I did a Computrainer FTP test (with my stages calibrated on left crank arm) and sure enough, my stages numbers are low (Computrainer 270 FTP, Stages FTP 218). I find this remarkable as I too, like OP, have viewed the DC rainmaker video where his power readouts are similar during testing ride.

Bottom line: Stages has been reliable and repeatable since purchase Jan 2014 and provides the feedback I am looking for to train and race. Also, when I had issues with power drop out occurring on my Garmin, Stages customer support had me up and running with a replacement cover in 2 days. They understand customer support and have been available when I've called.

Thanks again for your post

This is an excellent example of why one should limit power meter choices to ones that allow for at least checking of the torque slope calibration, if not allowing for "in situ" torque slope calibration.

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http://bikeblather.blogspot.com/

Wow, thats a big difference!

I might take Dunbar up on his offer. Im starting to think my 185 easy pace on stages is roughly 210-215 on Powertap. Maybe even more based on MPH average from rides last year to this year.

It's very frustrating to be honest. Plus, my 3sec average doesnt seem as stable as last year. Many more high/low spikes.

LOL!

Forgive me for my naivete but does the new PT pedals fix my problem in your mind?

I don't know...can you do a static check on them with a known weight after they are installed? I haven't been paying attention.

That said, judging by their hubs, PT products are typically VERY well calibrated out of the box...but, the new pedals (and chainring PM) add another level of uncertainty as compared to the hubs due to the installation vagaries...

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http://bikeblather.blogspot.com/

How do you know that over the last 2 years your left right balance has remained stable?

Have you kept the powertap to check occasionally?