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Thread: Team efficiency

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    Team efficiency

    Just wondering if you have experienced either being part of, or ridden with teams that seem to not perform on a tandem as well as you would think they would going by their single bike speed.
    Recently my wife and I (we have been tandeming for years) rode with my brother and his friend (who have only ridden together a few times).
    Going by their single bike performance I would say that the average of their hill climbing speed (watts/kg) was at least equal to ours and as they are heavier their flat land speed average would be superior.
    But when we rode on our tandems we were significantly stronger than them on the hills, and could match them on the flat.
    There is obviously something going on here with how the dynamics of the two people work together to power the bike along. I sort of knew this already but had never experienced it.
    Anyone know if any science/research has been done on this, and is there any specific training that can be done to improve it?

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    Tandem Vincitur Ritterview's Avatar
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    If you want to analyze this, and determine if there is some factor beyond watts, kilograms, air drag, rolling resistance, and drivetrain efficiency, then plug a range of estimated numbers for the tandem teams into the Kreuzotter Speed & Power Calculator, and see if the answer cannot be found in the the known, prior to invoking some new and unknown factor, which, like duty, goes on in time and space, and beyond time and space.

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    Senior Member ftsoft's Avatar
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    Hi Dean. Hows it going? There are a lot of factors involved in climbing aside from the numbers. Types of climbs, rhythm, mood, climbing style. Terry and I are pretty slow climbing for instance, even though I'm a passable climber. But I tend to climb out of the saddle a lot and Terry isn't really comfortable or fit enough to do this on the tandem. So, our styles don't mesh very well.

    Frank and Terry

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    just another gosling Carbonfiberboy's Avatar
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    It's usually a difference in pedal stroke. One person is attempting to accelerate the other person's feet and legs during a part of the stroke. Some people can accommodate these differences by slightly changing the phase timing. It takes practice to feel the other person's stroke and then some communication to figure out what to do about it, and then some time for one or both to change their default pedaling style.

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    After many thousands of miles of riding over many years with different pilots of varying levels of ability, I believe the single most important factor in riding well on a tandem, is riding as one. Over short distances, around 1 km, I suspect that simply adding the power of the riders may well give a good approximation of overall performance and 2 very powerful riders will typically be faster than 2 less powerful riders. However, over longer distances, the delivery of force to the pedal by each rider arond each pedal cycle becomes increasingly important.

    I don't believe 2 riders can ever pedal perfectly in synch with each other. And by that I mean deliver precisely the same force in the precisely the same direction around every single point of every pedal stroke. It follows that whenever they are not pedalling in synch as described above even for a fraction of a second, , one of the riders is tryingto accelerate the entire bike on their own. This may only be for a fraction of a second, but could occur many times throughout each pedal cycle. Over time, these differences fatigue both riders more quickly than they would fatigue as individuals and hence over all combined performance is compromised.

    In my experience, the best way to reduce this affect is simply to do as much riding as you can with whoever you race with. This is probably why you and your stoker are faster than 2 otherwise potentially stronger individual riders on a tandem.

    However, it is possible to simply just ride better with certain people from the outset, probably because you just happen to have very similar pedalling styles. And likewise, even if you ride with someone else a lot, it doesn't follow that you will ride well with them in a race. You just both might not be particularly well matched riders.

    So anacdotally, based on my experience, this seems very clea to me. Indeed, I'm sure others would agree that sometimes you can simply feel a tandem accelerate when both riders don't necessarily put in a massive effort. You just seem to hone in to each other and it feels great, smooth, effortless in comparison. It may not last for long but that is what I try to do when riding with whoever.

    I've also heard many pilots say that riding a tandem feels heavier than a solo bike. While this obviously could be directly attributed to one rider being stronger than the other, I know that I am stronger than some ofpeople who I ride with who also say the same thing and I know I have worked hard on the ride.

    And I believe this is also supported by the fact that it is harder climbing on a tandem as well. Typically your cadence is slower and pedalling style tends to be more punchy and these differences potentially exaggerated.

    We have also beaten other teams, even over short distances, who's combined power output on a static bike individually is significantly higher than our combined power output, and on very similar setups.

    This all makes perfect sense to me although I have no scientific evidence or proof of the affect.

    I'm not exactly sure how the Da Vincci independent drive chainsets work but if they do indeed allow eiher rider to pedal independently in a different gear, it woul be interesting to hear how riders using this drive train relate to any of the above. It think it is a little more complicated than this since riding together when linked in a conventional drive train may give more feedback to each rider and help improve any discrepencies in pedalling, as well as potentially reduce mechanical losses, but it still would be interesting to know.

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    Senior Member zonatandem's Avatar
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    While folks may be great riding their solos, put'em together on a tandem and they are not quite as great as a duo.
    In our younger days we have beaten folks who were great solo riders and on a tandem tried to beat us in a distance events. No luck on their part.
    Clearly, mega-miles TWOgether on tandems will give you a distinct advantage.
    Pedal on!
    Rudy and Kay/zonatandem
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    I'm not exactly sure how the Da Vincci independent drive chainsets work but if they do indeed allow eiher rider to pedal independently in a different gear, it woul be interesting to hear how riders using this drive train relate to any of the above. It think it is a little more complicated than this since riding together when linked in a conventional drive train may give more feedback to each rider and help improve any discrepencies in pedalling, as well as potentially reduce mechanical losses, but it still would be interesting to know.
    I'm a happy daVinci stoker, and I can at least say that the captain and stoker do not pedal independently and do not pedal in different gears. When both are pedaling you feel that resistance and pedal at the same cadence just the same as you would with a conventional tandem. What the daVinci will allow is for the stoker to take a break and coast for a bit while the captain is still pedaling. Likewise the captain can stop pedlling and coat while the stoker continues to pedal. When either of the two coast, particularly if it is a slight hill, the bike will lose some momentum since you don't have two people putting forth effort. The ICS (Independent Coasting System) is useful for standing, stretching, fumbling in the rack bag and getting water. Also useful for starting out while on hills or just waiting for the captain to get fully clipped in while the stoker pedals.
    Last edited by bikefor2; 05-15-11 at 04:42 PM.

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    Senior Member zonatandem's Avatar
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    ICS on daVinci tandems is exactly as it says:
    Independent Coasting System . . .
    NOT independent cadence.
    Pedal on TWOgether!
    Rudy and Kay/zonatandem

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    I once tried out a "faster" stoker with the intent of evaluating a possible race setup. He couldn't give up control of the bike so I tried stoking for him. That worked out better but the results were unimpressive. The bike felt like a noodle and I suspect very little of our exerted energy was actually making it to the ground.

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    Senior Member mkane77g's Avatar
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    Been riding tandems 25yrs. with the same person. Practice makes perfect.

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    Senior Member waynesulak's Avatar
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    I would like to hear more from those who have ridden with many stokers. From my limited experience, mismatched but powerful stokers may not feel smooth or even be very fun but it can be very fast.

    When comes to watts quantity has a quality all it own.

    Wayne

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    IMO, the big problem with poorly-synced teams is that the riders aren't in sync with how they modulate their efforts. I.e. if I'm captaining the tandem, I might want to increase the team power output to 150% of the team's combined sustainable power to close up a gap or power up a short hill. If my stoker keeps his power output at 100%, I might have to surge to 200% to close the gap. So I'm killing myself, really going anaerobic and wearing myself out extra quick, when if we both upped our power output to 150%, we could close the gap without "burning so many matches".
    I don't even use the offensive term "Fred." -- Sheldon "All Cyclists Are My Friends" Brown (1944-2008)

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    Senior Member zonatandem's Avatar
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    We used to teach tandeming, so have literally ridden with over a hundred different stokers.
    The worst was with a guy who called himself 'a racer' . . . he kept throwing his body weight around. He was neither good, smooth or fast . . . except in his own mind!
    The most fun were the stokers who had never ridden tandem . . . they were all (eventually!) smiling!
    Pwedal on TWOgether!
    Rudy and Kay/zonatandem
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    just another gosling Carbonfiberboy's Avatar
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    Quote Originally Posted by Phantoj View Post
    IMO, the big problem with poorly-synced teams is that the riders aren't in sync with how they modulate their efforts. I.e. if I'm captaining the tandem, I might want to increase the team power output to 150% of the team's combined sustainable power to close up a gap or power up a short hill. If my stoker keeps his power output at 100%, I might have to surge to 200% to close the gap. So I'm killing myself, really going anaerobic and wearing myself out extra quick, when if we both upped our power output to 150%, we could close the gap without "burning so many matches".
    Yes, right on. Stoker and I both wear coded HRMs. The really weird thing is that after the first 5 or 10 miles, our HRs are synched up. We call them out to each other just to make sure, but mostly we're about the same. If I power up, she powers up. If I back off, she backs off. If I want to attack, I say "Accelerate" as softly as I can. Otherwise, I usually don't have to say anything. We're not exactly sure how this works, but I'm sure it's something about the feel of the pedals.

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    PMK
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    Finally getting all the input info in one location has helped us step it up a bit more.

    No more questioning the stoker for HR, now I watch her immediate trends. The inputs of cadence, Captain HR, Stoker HR, speed, and feel of how the pedals are turning (mashing or spinning) makes keeping us stronger longer, while keeping speed up with less effort more attainable.

    The one almost invisible parameter is the wind. I watch for flags, waves or any other indicator of the wind direction. This allows a better assesment of the effort vs the speed.

    Off-road is entirely different. However, there I constantly ask stoker HR on climbs or areas where it may be a factor. Unfortunately, as often as it may be a higher HR, there are many times it is very low, usually in technical areas where she does not want to go fast.

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    ++ Heart Rate

    The purchase of Cateye V3 was the best thing we did to even out the load. Heart rate will definitely tell you who is working the most once you know where your normal cruising rate is.

  17. #17
    The Jet Stream Alex & Deya's Avatar
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    We consider our selves an efficient team. Although we don’t ride the tandem as much somehow we don’t need to speak much, it just seems that we can tell what needs to happen and we do it almost at the same time. I believe it helps that we also ride and work together as a team on our singles.

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