Off-set crankarm positions.
05-17-07, 05:48 AM
#1
Ride more, eat less
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Off-set crankarm positions.
I don't quite understand why some tandem couples have off-set crankarms between the captain and stoker.
For example, when one rider's drive side crankarm reaches the bottom of the stroke, the other rider's drive side crankarm is not at the same position, why and how does that benefit the combined ride of the tandem?
The whole concept seems rather confusing and new to me, could anyone give some explainations?
My stoker and I are riding a semi-recumbent tandem, similar to a Hase Pino or Bilenky Viewpoint:
What kind of off-set between the crankarms should we have in order to balance out our pedalling efforts?
For example, when one rider's drive side crankarm reaches the bottom of the stroke, the other rider's drive side crankarm is not at the same position, why and how does that benefit the combined ride of the tandem?
The whole concept seems rather confusing and new to me, could anyone give some explainations?
My stoker and I are riding a semi-recumbent tandem, similar to a Hase Pino or Bilenky Viewpoint:
What kind of off-set between the crankarms should we have in order to balance out our pedalling efforts?
05-17-07, 07:18 AM
#2
TWilkins
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Do a forums search for Out of Phase or OOP, and you'll find lots of information. In an abbreviated version, riding OOP is a way to even out he pedal stroke between the two. For example, when the captain is at the "dead" part of his stroke, the stoker is just coming around.
We're riding that way for the first time this summer, and it takes some getting used to, but once we got it down, it seems to help us climb a little better, and our average speed (or lack thereof) may be just a tad bit faster.
We're riding that way for the first time this summer, and it takes some getting used to, but once we got it down, it seems to help us climb a little better, and our average speed (or lack thereof) may be just a tad bit faster.
05-17-07, 07:45 AM
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The major, alternative crank phase configurations are illustrated here with some notes on what each configuration favors in terms of workload:
https://www.thetandemlink.com/Images/crankphase.jpg
This recent thread pretty-well covers most of the discussion points on in-phase vs. out-of-phase
https://www.bikeforums.net/tandem-cycling/267643-poll-do-you-ride-phase-out-phase-do-you-like-better.html
As noted, the archives are littered with previous threads on the subject. Some teams can benefit from riding out-of-phase whereas others will not see any real benefit.
https://www.thetandemlink.com/Images/crankphase.jpg
This recent thread pretty-well covers most of the discussion points on in-phase vs. out-of-phase
https://www.bikeforums.net/tandem-cycling/267643-poll-do-you-ride-phase-out-phase-do-you-like-better.html
As noted, the archives are littered with previous threads on the subject. Some teams can benefit from riding out-of-phase whereas others will not see any real benefit.
05-17-07, 12:32 PM
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Try it for a couple hundred miles . . . you may like it. If not, switch back to in-phase.
Been 90 degrees OOP for over 32 years . . .
Been 90 degrees OOP for over 32 years . . .
05-18-07, 10:15 AM
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We tried both in phase IP and out of phase OOP. We are 90 degrees OOP.
Pros – Increased our average speed 5% with the increase coming from hill climbing improvement. Lower peak torque for the same power input which results in less stress on the drive train, eliminates whooshing noise and less frame flex under full power.
Cons – Lower peak torque results in lower acceleration in sprinting, management of pedal clearance over speed bumps can be a problem, stoker must start cleated in on the bike and some teams find IP more aesthetically pleasing and like the whooshing noise.
Pros – Increased our average speed 5% with the increase coming from hill climbing improvement. Lower peak torque for the same power input which results in less stress on the drive train, eliminates whooshing noise and less frame flex under full power.
Cons – Lower peak torque results in lower acceleration in sprinting, management of pedal clearance over speed bumps can be a problem, stoker must start cleated in on the bike and some teams find IP more aesthetically pleasing and like the whooshing noise.
