# Newbie question about crank sync



## solidass (Jan 20, 2013)

I've only been on a tandem once my entire life. I'm totally out of touch.

So as a complete non tandem rider (outside observer whatever), I wonder about the need for crank sync. And about the general lack of freedom between riders.

Why don't they make crank axles for tandem such that forward pedaling is power but reverse is free? This way, either or both rider can choose to apply power or not at any time and each can stay on the pedal all the time.

Or is this already available? Forgive me for such a newbie question.


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## Okayfine (Sep 7, 2010)

They already do.

daVinci Designs - Performance Handbuilt Tandem Bicycles | with Independent Coasting Drivetrain

There are reasons why most tandem manufacturers don't do something like that, but it is purely about how you and your stoker like to ride. And what terrain you like to ride. Having the cranks in sync lets the captain know where the pedals are in order to (help) avoid pedal strikes. There are other issues, but they're personal likes and dislikes and for the most part can be overcome with additional communication.

Search in this forum for ICS and you should find a couple previous threads.


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## solidass (Jan 20, 2013)

Awesome!

ICS would be Independent Coasting System as a patented _daVinci Designs_ feature?

IPS seems to be Independent Pedaling System by other makes.


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## de lars cuevas (Jun 19, 2006)

I have piloting experience in tandem road racing (and occasionally as a stoker). On a racing tandem, you want the cranks to be parallel, especially for "powering out of the saddle". Out-of-sync cranks will make the bike hard to control for the pilot!

I often raced with visually impared stokers. You definitely want parallel cranks then . I also have done some mountainbike tandeming with blind stokers. Same goes&#8230;

So to be honest, I was quite sceptic about independent drives&#8230;

However, last weekend I got to try a tandem with an independent drive for the first time: Zion Tandem - Ride with Style. Ride MSC Bikes This bike has a simple one-way clutch in each right crank.
My stoker for the day also has road racing piloting and stokering experience.

And&#8230; as soon as we got on the bike, the scepsis was gone! It helps when taking of. It helps when maneuvering around tree roots. It helps when you want to adjust your shoe buckle, it helps in the rough stuff when I was too busy steering to pedal, while my stoker just kept on pedaling, keeping the momentum.

Some instability was felt when going out of the saddle, but, the bike being big and stable, not as much as I thought it would. And of course, when needed, the stoker sync the cranks roughly.

So all in all, we were pleasantly surprised, an independent drive can really be an upgrade!


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