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mooncricket 10-31-07 09:20 PM

Un-Synchronized Tandem?
 
Hi,

I'm entirely new to tandem cycling though not to cycling.

Someone told me about a new (?) type of tandem where the stoker and the captain don't have to synchronize their pedal stroke. What's the term I'm looking for? (I did a quick search of the forum but didn't find anything)

Has anyone tried such a bicycle? What are the disadvantages/advantages of such a system? Who is best suited of this type of riding?

Thanks for all replies!

Cheers

TandemGeek 10-31-07 09:42 PM

Independent Coasting System (ICS) by www.daVincitandems.com

Do a search of the archives using the terms ' daVinci tandem ' and you'll find several threads.

There are also a few other systems like this on the market, e.g., ATP Independent Pedalling System (IPS) which first appeared on Vision Recumbents tandems. Produced and marketed under license to someone else following ATP / Vision's demise a few years back. There's also a cruiser bike on the market with a jackshaft for ICS/IPS like crank action.

mooncricket 10-31-07 10:27 PM

Fantastic! Thanks!

zonatandem 10-31-07 10:28 PM

Advantages:
Each rider pedals/coast as desired. Especially great for newer tandem duos.
A great conversations starter!
Confuses the heck out of folks behind you who want to count your cadence!


Disadvantages:
By not being constant in or out-of-phase, it can create tandem sway, especially when stomping/climbing. If leaning hard into a corner 'could' cause a pedal to scrape, but most tandems (unless really racing) do not lean into corners that hard.
If you want to pedal in phase, or out-of-phase, with an ICS tandem, stoker has to visually check captain's foot position and then co-ordinate her pedal stroke (or disable the ICS system).
More expensive and complex than standard pedaling system.
Has 3 bottom brackets instead of 2.
A bit heavier (if weight is a concern).

Test ride both systems and then decide TWOgether!

Yes, have ridden ICS equipped tandem. No, do not own one.

Xanti Andia 11-01-07 06:39 AM

Do keep in mind that Independent Coasting does not permit differing cadences between riders, only the choice to spin or not to spin, once you are spinning you cannot deliver power to the pedals at different rpm.

In some rare Independent Pedaling recumbents, as TG pointed out, each rider has his own transmission to his own wheel, so each can choose his cadence.

I have not tried either one.

zonatandem 11-01-07 11:16 PM

As Xanti Andia pointed out some systems are able to do different/individual cadences + independent coasting, but that usually involves a 3rd derailleur.
And yes, rode of of those too.

Leigh_caines 11-03-07 04:30 AM

I made my own...
I mean I addapted a cheap tandem by putting "freewheels" on both cranks
The ' daVinci tandem ' is way out of my price range.

>>Has 3 bottom brackets instead of 2.<<
Can be but dosen't have to be [our one is 2]

My lady stoker loves it... and now so do I
See Thread "New One" for pic

You can change the "cadences between riders" if you want [if one rider is a lot faster spiner then the other] by having less teeth on one crank [I've done this as my lady is somewhat disabled and needs to spin slower]

There are lots of ways to go... just keep thinking outside the square

Leigh_caines 11-03-07 04:33 AM

O... cost was $100 Aust for 2 freewheeling cranks off e-bay

mooncricket 11-07-07 01:12 AM

Thanks all. Much appreciated.

I'll be traveling to Taiwan so I'll probably pick up one of the cheaper DaVinci knockoffs over there.

Basically, my gf is an adequate athlete so I consider myself pretty lucky already. I don't want to make her work too hard to get into the cycling/touring thing, otherwise it would put her off for good. It pretty much boils down to either she gets on the bike with me or be left behind for weeks/months at a time.

Thanks again all.

Xanti Andia 11-07-07 12:30 PM

Mooncricket, before you go into all the trouble of installing an Independent Coasting mechanism, you ought to try riding a regular tandem for a while. Many teams (including ours) have the differences in ability which you describe, and manage fine without it. It is a matter of compromise on the cadence, and communication. You will need compromise and communication in any case, so why not apply it to the crank? The actual power delivered to the pedals is always independent.

Independent coasting looses a communication link which is the sych chain, you might be surprised how much is carried between the riders by this simple chain, once you have settled into your team habbits. I hardly call the bumps for example, my stoker knows that if I stop pedaling and I raise my butt, a bump is likely coming, a form of dancing. Independent Coasting also adds weight and complexity to the bike. Though there are riders who swear by it is a small minority of the tandem population, it might look like a good idea, but why not find out first if its a good idea for your team?.

PlanetU 11-07-07 11:08 PM

Quote:

Originally Posted by Xanti Andia (Post 5591461)
Mooncricket, before you go into all the trouble of installing an Independent Coasting mechanism, you ought to try riding a regular tandem for a while. Many teams (including ours) have the differences in ability which you describe, and manage fine without it. It is a matter of compromise on the cadence, and communication. You will need compromise and communication in any case, so why not apply it to the crank? The actual power delivered to the pedals is always independent.

Independent coasting looses a communication link which is the sych chain, you might be surprised how much is carried between the riders by this simple chain, once you have settled into your team habbits. I hardly call the bumps for example, my stoker knows that if I stop pedaling and I raise my butt, a bump is likely coming, a form of dancing. Independent Coasting also adds weight and complexity to the bike. Though there are riders who swear by it is a small minority of the tandem population, it might look like a good idea, but why not find out first if its a good idea for your team?.

I agree, wholeheartedly. We tried a DaVinci at the Outdoor Demo and, frankly, we hated being out-of-sync. From the stoker's standpoint (me) the bike felt jerky and unstable. We went out of our way to peddle at different tempos to see how it felt; and after a few miles, we wound up back in sync anyway, because it felt so horrible not to be.

My Husband/Captain is a much, much stronger and faster rider than I am - but we've learned to compensate; and have done very well on centuries, double centuries, and touring. And we both agree that standard tandem cranks are way, way better! We'd NEVER switch.

Good luck!

Deb

Leigh_caines 11-08-07 01:50 PM

>we hated being out-of-sync.<

No that is not what happens...
we have only been ride as a pair for two months...
but within a few days we rode "in-sync"
My lady can see my legs go around and she likes to get in time.
The huge advantages are [for us]...
Starting off [remembering my lady is disabled] is very smooth [no delay while I clip my feet in]
I never jerk her by going backwards [even a little bit dose jerk]
And the big one is... she can rest while I keep going [in our case this is half the rideing time] she get out of the house and goes farther then she ever could before. We go places she couldn't go on her own.
So for us having freewheeling is the best thing ever!!

TandemGeek 11-08-07 01:56 PM

Quote:

Originally Posted by Leigh_caines (Post 5598239)
...but within a few days we rode "in-sync"

This is also what most of the teams whom we've ridden with or know who ride daVinci tandems report. Riding out-of-sync is something that seems to occur under just a couple of different scenarios:

1. Intentionally on long seated climbs
2. When one rider decides to coast or soft pedal for a break
3. When one rider becomes fatigued and unitentionally soft pedals**
4. When a kid-back is riding and does what ever it is that kids do on the back of tandem when not required to stay-in-sync.**
5. When riding technical single track off-road and negotiating hazards.

**This is a blessing in disguise to captains who might otherwise find themselves pushing their stoker's feet around.

Leigh_caines 11-08-07 02:09 PM

1- yes
2- since I always pedal and she cuts in in time.. not a prob
3- hasn't happened
4- have to wait for my grandaughter to visit :)
5- hope my lady get to this stage

masiman 11-08-07 02:16 PM

Quote:

Originally Posted by Xanti Andia (Post 5557016)
Do keep in mind that Independent Coasting does not permit differing cadences between riders, only the choice to spin or not to spin, once you are spinning you cannot deliver power to the pedals at different rpm.

In some rare Independent Pedaling recumbents, as TG pointed out, each rider has his own transmission to his own wheel, so each can choose his cadence.

Not quite true regarding cadence for the ICS system. Since each crank has it's own chainring that drives the "jack gear", by varying the captain or stoker chainring, you can change the relative cadence. I.e. put a larger drive chainring on the stoker crank and the stoker will have a lower cadence than the captain. Much the same as Leigh Canes stated for his 2 BB system.

Quote:

Originally Posted by Tandemgeek
This is also what most of the teams whom we've ridden with or know who ride daVinci tandems report. Riding out-of-sync is something that seems to occur under just a couple of different scenarios:

1. Intentionally on long seated climbs
2. When one rider decides to coast or soft pedal for a break
3. When one rider becomes fatigued and unitentionally soft pedals**
4. When a kid-back is riding and does what ever it is that kids do on the back of tandem when not required to stay-in-sync.**
5. When riding technical single track off-road and negotiating hazards.

**This is a blessing in disguise to captains who might otherwise find themselves pushing their stoker's feet around.

+1 to Tandemgeeks scenarios. I would only modify #2 and 3 to indicate a broader spectrum of intentional and unintentional soft pedaling (tired, distracted, perturbed, adjusting, drinking, etc.).

Just as PlanetU would not switch to ICS we currently would not want to switch from it. It has its advantages and drawbacks.

adamlaw 11-08-07 06:57 PM

I have been riding a Bob Brown tandem with a DaVinci Independent Coasting system as a newbie to tandem riding. It has been great. My 10 and 12 year old stokers have taken to it easily. They automatically end up in phase without any conscious effort. We haven't practiced out of phase - that is likely more difficult. It makes starting very easy. Also, it provides a huge range of gears with 4 chain rings on the front and 10 on the back!

RogerD 11-12-07 03:18 PM

Mooncricket,
Not to infer ignorance on your part (or maybe I misunderstood your question), but I've heard some people express the notion that tandem riding is really hard because you have to learn to pedal together. Not true. With a normal tandem, the chain connecting the front and rear cranks forces you to pedal together, whether in or out of phase. So there is no problem in "having to synchronize their pedal stroke." My wife and I have vastly different fitness levels; on her own she'd probably ride at 12-13 mph, while I cruise at 17-18. But we are a fine tandem team. You'll find the compromise through good communication (remembering that anything wrong is not the stoker's fault). Maybe you'll need to ride less aggressively than you would on your own, but that's a small price to pay for companionship. And she might find that as she gets stronger she can ride faster than she thought.

zonatandem 11-13-07 05:10 PM

Mooncricket ;

Issuing utlimatum of 'she gets on the bike with me or get left behind for weeks, monhs at the time' . . .?!
It takes 2 people to make a good tandem 'team'.
If you two are not willing/able to compromise a bit, then why bother riding TWOgether?


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