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Monitoring captain and stoker efforts

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Monitoring captain and stoker efforts

Old 08-22-22, 09:19 AM
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Iawestrr
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Monitoring captain and stoker efforts

Do any of you teams have a good way to monitor the power (watts) being delivered to the pedals by the captain and stoker? Can this be accomplished with both captain and stoker having odometers? Or do we need to invest in pedals that measure watts? I know nothing about them. Do they also measure the foot doing the upswing, or do they just measure the foot doing the down swing? Would this also require devices of some type mounted on the front and back handle bars so that the team can see the watts of both?
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Old 08-22-22, 09:36 AM
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Simple test: take your feet off the pedals while the stoker continues to push and see what happens. If the bike slows precipitously, you can say, "You're not pulling your own weight."

This presumes that (a) you're the captain and (b) you're experiencing tandem paranoia about doing more than your share of the work. Both are likely valid assumptions, in my experience.

Unless measuring the relative levels of power output in crucial to some training plan, try not to worry about how much work each rider is doing. The main virtue of tandems is that they allow riders of dissimilar ability to ride together without the weaker rider having to struggle to keep up or the stronger rider having to sandbag.
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Old 08-22-22, 02:34 PM
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If you really want to know accurate watts you have to get power meters and the most "affordable" ones go into the pedal axle. Most riders don't go this route because it's still pretty expensive. Google "Garmin Vector 3" to get an idea of what the costs are.

A cycling-specific app with GPS and an HR monitor can do some gross estimation of power but it's typically not accurate enough for anything other than relative effort.

Honestly if you want to get good power data and get a little more bang for your buck, a smart trainer is a decent compromise (cost and usefulness).
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Old 08-22-22, 09:18 PM
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My stoker and I both have Assioma power pedals.
I have on occasion had curiosity to wonder: "how much effort is that stoker really putting down", and these do let me check, but only with a second head-unit on my handlebars (because you can only pair a head unit to one powermeter).
My stoker is remarkably good-natured, but if yours is not, I caution against such foolish and expensive pursuits.
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Old 08-25-22, 10:48 AM
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On our tandem, captain wears a Garmin heart rate (HR) strap. Stoker wears a Polar HR strap. We both have Garmins which show HR, so stoker's Garmin shows captain's HR. Stoker also has a Polar watch which shows her HR, so she tries to keep our two HRs in sync. Because stoker's HR is naturally higher than captain's, she has to keep her HR a bit above captain's. This is not a perfect system, but it's not horribly expensive and it works. The downside of our system is that HR lags effort. As we start to climb a hill, captain's effort goes up immediately, but stoker won't see it until captain's HR comes up. Going over the top, captain's HR will still be high even though the effort is lower. This is more of a PITA in a paceline than just riding along.

One could also use power, which would be better. We had the HR equipment already, so that was cheaper for us. So yes, you buy power pedals and then 3 head units to display the readings: two for the stoker and one for the captain. In our household, it's better that way. Stoker is in charge of matching effort. Using power, stoker tries to match some percentage of captain's power. If you both find your FTP (functional threshold power), you can figure what percentage stoker should use. Power readings go up immediately with effort, so that would be nice.

Having two Garmins for navigation is really nice. Stoker is navigator, which frees up captain's eyes and attention, safer. Then there's one more power head unit for Stoker, which could be less expensive.
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Old 08-26-22, 05:38 AM
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I too have been curious about this and devised a way that I think you can capture fairly accurate data with a single set of dual sided power meter pedals. My interest was both curiosity and to convince myself that my stokers claims that she was working just as hard as I was were indeed true. Always looking for a bargain, I invested in the IQSquared cheapo power meter on Kickstarter and while I am still sitting by the mailbox waiting for them to arrive I will share what I had in mind.

With just 1 set of dual sided power pedals, do several representative rides with both pedals on the front and capture the data. Looking at the Left/Right power balance, calculate an average L/R balance for the captain. Then move the pedals to the stoker and do the same - calculating an average left/right power balance for the stoker. Here is where the brilliance comes in: Put one of the pedals on the captains crank and one on the stokers crank. After capturing a rides worth of data, import the data into Golden Cheetah where you can see and edit both both pedals power data. For the captain, copy the captains pedal data to the other pedals data and apply the appropriate captains L/R balance. This should give a pretty close overall picture of the captains ride power. Then do the same for the Stokers data. You should now have a good data set for both riders power to compare (and settle those outlandish claims once and for all ).

There is some off bike work to do here that may involve spreadsheets and graphs, and it requires that both captain and stoker use the same, or compatible, pedal cleats. If you didn't want to go the route of importing and manipulating the data in a spreadsheet, you could do the same and just apply the L/R balance to the average power from the ride. This number would not be too interesting to me as all it would show is that the power from both riders is different.
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Old 08-26-22, 05:28 PM
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Originally Posted by Alcanbrad View Post
I too have been curious about this and devised a way that I think you can capture fairly accurate data with a single set of dual sided power meter pedals. My interest was both curiosity and to convince myself that my stokers claims that she was working just as hard as I was were indeed true. Always looking for a bargain, I invested in the IQSquared cheapo power meter on Kickstarter and while I am still sitting by the mailbox waiting for them to arrive I will share what I had in mind.

With just 1 set of dual sided power pedals, do several representative rides with both pedals on the front and capture the data. Looking at the Left/Right power balance, calculate an average L/R balance for the captain. Then move the pedals to the stoker and do the same - calculating an average left/right power balance for the stoker. Here is where the brilliance comes in: Put one of the pedals on the captains crank and one on the stokers crank. After capturing a rides worth of data, import the data into Golden Cheetah where you can see and edit both both pedals power data. For the captain, copy the captains pedal data to the other pedals data and apply the appropriate captains L/R balance. This should give a pretty close overall picture of the captains ride power. Then do the same for the Stokers data. You should now have a good data set for both riders power to compare (and settle those outlandish claims once and for all ).

There is some off bike work to do here that may involve spreadsheets and graphs, and it requires that both captain and stoker use the same, or compatible, pedal cleats. If you didn't want to go the route of importing and manipulating the data in a spreadsheet, you could do the same and just apply the L/R balance to the average power from the ride. This number would not be too interesting to me as all it would show is that the power from both riders is different.
Right. And not interesting at all to this team. I don't care about her percentage of my power. I already know our FTPs, so that pretty much settles it. What stoker wants to know, actually much more than I want to know it, is how hard to go, all the time. Not to go too hard and waste energy, nor to go to easy and wear me out unnecessarily. That takes real time observation of both our outputs. Our cheapo method with HRMs, which we would wear anyway, and her Garmin, which she would have anyway, sort of works, but it's frustrating for her to not know exactly what to do, all the time. I know when to increase or back off the power, but because my power dominates our pedal system, it's hard for her to know what to do - except by watching my HR. Her power is not insignificant. She makes about 60% of my power when she's on top of it. That's a lot.

One time, climbing a short steep riser, I cramped both legs. She pedaled us up it, though she was quite shocked to feel the weight of the whole bike in her pedals.
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Old 08-28-22, 08:08 PM
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This actually sounds fun, since I tandem with several VI stokers. I could compare them to each other and tease them about being slower/ faster than my other stokers.
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Old 09-01-22, 07:56 AM
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@Iawestrr, what are you hoping to do? Don't do this if you want to fuel a dispute you've been having.
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