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Tandem Cycling A bicycle built for two. Want to find out more about this wonderful world of tandems? Check out this forum to talk with other tandem enthusiasts. Captains and stokers welcome!

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Old 07-11-16, 09:39 AM   #1
Philly Tandem
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Triplet/Quad riders: cranks out of phase?

We've had a Santana Cabrio triplet for 5-6 years now, and have lots of good miles under our tires on it. As our son has gotten older (he's 11 now), it's begun to feel like he is not "pedaling his own weight" since he's also gotten heavier. He's a pretty strong biker on his single bike, and definitely contributes great "turbo boosts" to the triplet when needed. But I feel like maybe he's not getting enough feedback through the pedals on the triplet to be able to gauge his effort. (We've talked with him, and he swears he is pedaling hard.) Or maybe I'm just perceiving his input to be not up to par.

So... I'm interested in hearing from any triplet owners who have tried out-of-phase cranks. I know on a triplet that it would definitely help smooth out the power flow, but I'm also worried about the potential for hitting pedals around curves, etc. If you've tried OOP on a triplet, quad (or longer) bike, how did it work for you? How much OOP did you go? Just a few teeth on each position (like captain leading by 10 teeth, middle position by 5 teeth, etc.)?

I am NOT looking to start a general crank phase discussion, but specifically looking for input on 3+ seater bikes.
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Old 07-11-16, 02:51 PM   #2
Paul J
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I have no experience with triples but wonder if you put his crank a tooth or two ahead if he would feel more of the pressure of pedaling as the first in on the down-stroke and give you a little bit more effort?

Last edited by Paul J; 07-12-16 at 07:12 AM.
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Old 07-12-16, 05:55 AM   #3
Tony Marley
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I have kept the pedals in-phase on our triplet due to the concern about a pedal hitting the ground in a turn. But I, too, sometimes feel like the older one is not contributing as much power, despite the increased weight.
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Old 07-19-16, 11:37 AM   #4
Philly Tandem
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I did move the cranks a few teeth OOP and on a 10-mile test ride it felt a little bit better. Not sure if I was imagining it or not, though! I may try a few more teeth OOP on the next ride. I am still reticent to go too far OOP, due to the potential for hitting a pedal on a turn. For those who haven't ridden triples (or longer), the longer wheelbase puts the center cranks lower to the ground in some situations, increasing the possibility of "grounding."
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Old 08-31-16, 12:30 PM   #5
Philly Tandem
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OP here, reporting back after going OOP for the past month, including on our tour in Europe. I put my son's cranks a few teeth (~4-5) out of phase, leading, and it seems to have made a huge difference. I think he can feel his input now (and so can I), and is definitely pedaling harder. I kept my wife's and my cranks in phase with each other, with his (in the middle seat of the triplet) leading. Since we weren't out of phase much, there were no cornering/pedal strike issues.

So, success! :-)
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Old 09-11-16, 09:22 AM   #6
tie dye tandem
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We have a Santana quad and while both our 2 person tandems are in phase, the quad has each rider about 45˚ behind the one in front. This was recommended to us by Bill and the folks at Santana so that we would have smoother power output, as you mentioned. We have had some pedal strikes with this set up. None has caused us to take a fall, but they can be unpleasant. My sense is that for our phasing the pedal strikes are inevitable, but how big a deal they are is highly influenced by the question of if we are pedaling or coasting when they happen. On an in phase or single set up the inclination is to coast in these situations to avoid a potential pedal strike. We don't really have that as an option. If we coast and do have a pedal strike on a speed bump or other feature, the impact is seriously notable. However, it we are pedaling and have a similar pedal strike, this is much less of an issue.

Glad your trip went well. We are in Spain now and have our Arriva S&S coupled tandem with us.

DT
Santana Quad, Arriva and Cannondale Road Tandem
plus many singles and unicycles too.
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