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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 07-13-05, 04:19 AM   #1
BNA roadie
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Out of phase cranks

Whose running a out-of-phase crank set up? any problems?
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Old 07-13-05, 07:19 AM   #2
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Originally Posted by BNA roadie
Whose running a out-of-phase crank set up? any problems?
I've got a 2005 Raleigh Companion, which I ride with an autistic stoker. We recently had the cranks switched out-of-phase, and I'm really happy with the results. In particular, hill climbing is much smoother this way.

Absolutely no problems so far!
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Old 07-13-05, 08:02 AM   #3
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I have a burley Rock and Roll and the cranks are slightly out of phase. Works fine.
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Old 07-13-05, 08:22 PM   #4
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Have pedaled 90 degrees out of phase (OOP) for over 200,000 miles on our tandems.
Love it! Works great for us.
Zero problems.
Try it for a few weeks. Then U-2 decide . . .
Pedal on TWOgether!
Rudy and Kay/zonatandem
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Old 07-14-05, 09:36 AM   #5
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Zonatandem:

Do you stand together?
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Old 07-14-05, 03:57 PM   #6
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No, we do not stand together. Easier climbing OOP, do not stand unless it's an emergency.
However, stoker and pilot can stand singly if needed. A bit more difficult for both to stand OOP . . . but have seen it done by only 2 couples.
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Old 07-15-05, 12:38 PM   #7
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We don't currently have our cranks out of phase, but we tried it for a while and did feel that it improved the smoothness and power of our seated climbing. We only put them a little out of phase, as we didn't want to make standing too awkward or sacrifice too much cornering clearance. It didn't seem to affect our ability to stand smoothly at all (although had they been further out of phase I'm sure it would have).
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Old 07-15-05, 03:35 PM   #8
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Quote:
Originally Posted by zonatandem
Have pedaled 90 degrees out of phase (OOP) for over 200,000 miles on our tandems.
Love it! Works great for us.
Zero problems.
Try it for a few weeks. Then U-2 decide . . .
Pedal on TWOgether!
Rudy and Kay/zonatandem
On wednesday we went for a ride with the cranks just slightly out of phase just to see what it is like. Didn't work for us at all and almost cut the ride short to change back. We carried on though, and both of us felt as though our knees had taken too much strain, as we were working off phase as well.
90 degrees might work, but after our experience on one ride, we'll stay in phase.
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Old 07-15-05, 08:34 PM   #9
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We actually have the opposite feelings about OOP . . .
Have ridden several test tandems in-phase and had leg strain climbing. OOP . . . no such problems. Always having a power stroke going 'over the top' at 90 degreees OOP is definitely our preferred way.
. . . . at least there's choices!
Pedal on TWOgether!
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Old 07-15-05, 09:48 PM   #10
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we are talking out of phase .. how much out of phase (90 45) I think this is something I would like to try. of course with her approval.

KB
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Old 07-15-05, 11:00 PM   #11
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Quote:
Originally Posted by slagjumper
I have a burley Rock and Roll and the cranks are slightly out of phase. Works fine.
As a captain, I have the opposite opinion - even one tooth out of phase (stoker leading, at the moment - my unintentional screwup) really throws off our non-verbal communication. Even with a very low number miles as a team, we jelled exceptionally well. When I'm hesitating on beginning a mash on the pedals, the stoker gets to her "oh, we're going" point just before the captain intended to commit. This interferes with our graceful exit from a stoplight track stand.

We also start to fight each other very slightly when coasting - the angle isn't quite the same. We are very sensitive/picky about bike fit. Once dialed in, we notice the slightest change in adjustment.

When slightly out of phase, I really feel the push of my stoker as I'm about to push myself, and it causes hesitation on my part - "why did my pedal just move on it's own?". When we go back to perfectly in phase, I don't feel her efforts as much, but rather the bike does what I expect it to.

As always, however, if it works well for your team, just go with it.
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Old 07-17-05, 05:28 PM   #12
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Any amount of out-of-phase is do-able.
However, for us, 90 degrees works best as there is aways a power stroke going 'over the top', either by stoker or pilot. Reduces flex on frame, avoids timing chain from popping off when hammering and, to us, feels smoother climbing + makes for quick get-away from traffic stops.
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Old 07-18-05, 09:33 AM   #13
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Zonatandem: We are thinking about trying OOP pedals. 90 degrees.... should we be concerned about hitting the pavement while cornering?
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Old 07-18-05, 09:44 AM   #14
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Quote:
Originally Posted by cornucopia72
Zonatandem: We are thinking about trying OOP pedals. 90 degrees.... should we be concerned about hitting the pavement while cornering?
Ours have been 90 degrees OOP for about a month now. I had the same concern initially, but I'm happy to say that we've experienced absolutely no trouble so far.
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Old 07-18-05, 01:12 PM   #15
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What's the best way to go from in phase to OOP? We've only had our tandem for about 3 months now and I haven't had to adjust tension on the timing chain yet. Is it easier to losen the EBB enough to derail the chain, adjust to OOP and then readjust the EBB? Or is it easy to just break the chain and then put back after adjusted to OOP? Seems like it would be hard to put the chain back together under tension but I've never tried.

Thanks for any help, I'm wanting to try OOP!
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Old 07-18-05, 02:09 PM   #16
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Quote:
Originally Posted by phil.
What's the best way to go from in phase to OOP?
Loosen the eccentric bottom bracket (EBB), and make your adjustments, then re-secure the EBB.

Note: With regard to setting the timing chain's tension, bolt-on timing rings don't always perfectly align with the spiders and if they're both off at the wrong place you can end up with the timing chain being too tight and alternatively too loose as the cranks go through a full rotation. This can make setting the timing chain tension a bit of a trick in that you need to catch it when it's at the tightest setting instead of the least tight to make sure it doesn't bind. Ideally, you should have about 1/2 of slack along the top of the timing chain run between the cranks and, keep in mind, when you tighten the eccentric the front axle will move forward 1mm - 2mm. Therefore, you'll want to get your chain's tension adjusted where you want it, and then you'll want to back-off of tension (rotate the eccentric) a little so that when you tighted up the eccentric the chain tension will be where you wanted it

Last edited by TandemGeek; 07-18-05 at 02:15 PM.
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Old 07-21-05, 08:38 PM   #17
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Landstander:
Unless you are racing and lay one hell of a hard corner you'll not hit the pavement. But, watch it coasting over some of these super high old fashioned speedbumps!
Phil:
Changing to OOP, is as suggested by Mark.
However, there is a quicker 'non-recommended' way: Derail chain by pedaling backwards while using a thin bladed screwdriver to derail chain off chainring. Set pedals up 90 degrees OOP; Put chain on one chainring, have someone lift rear wheel and pedal forward while popping chain on other chainring. Will work in 99% of the cases.

Pedal on TWOgether!
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Old 07-21-05, 10:11 PM   #18
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so any of you "teams" ride in the Dirt with this set up..

I have about 13' Bottom brackets and i still hit rocks and stuff all the time, i can not thing what will happend if we got a pedal stuck on something..

the concept is interesting for sure but sounds almost impossible to be used in the dirt..

actually I'm almost ready for a "Da-vinci" retrofit on my ibis in hope of increase chain ground clearance..

Oh another way to change the face on the cranks is to take the bolts of the chainrings and spin the cranks as many deggres as you need,,oviuslly 5 biolt cranks will not give you 90 but the FOUR bolt cranks are perfect..

anyway to increase longevity on the chainring i find over the years that is a great idea to rotate the chainrings (on the cranks) so they wear more evenlly, just another South American trick
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Old 07-22-05, 02:01 AM   #19
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If we're not perfectly matched in leg strength, would going out of phase help us?
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Old 07-22-05, 04:19 AM   #20
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Quote:
Originally Posted by ricardo kuhn
so any of you "teams" ride in the Dirt with this set up.
Absolutely not... with one exception; daVinci's ICS.

Let me elaborate: If your off-road riding is limited to forest service roads and non-technical trails where you will not encounter any obstacles, it's probably not a big deal. However, for those who ride technical terrain and single-track, having the cranks out of phase presents some serious safety concerns for the Stoker's feet. While there are some teams who will put the cranks one or two teeth out of phase, once you get beyond that you run a very high risk of driving your stoker's feet into logs, rocks, trees and other obstacles commonly found on the trail. While it's possible that a captain "could" have enough mental capacity to constantly remind himself of his stoker's pedal positions and remind himself to position the cranks to keep their feet clear of obstacles, my personal view is that anyone who has learned to ride single track on a personal bike will fall victim to "instinctive habits" that even make remembering in-phase crank positioning a challenge with regard modifying your ratcheting technique when grinding over logs, dropping over berms, or delaying the restart of pedalling when cornering around trees or stumps, anyone of which could slam a stoker's foot into the obstacle.

daVinci's independent coasting system -- which permits the captain and stoker to stop pedalling or to back-pedal independent of each other -- puts the burden of proper crank placement on the stoker AND has the added benefit of allowing the stoker's pedal to "give" and move backward if it does strike an obstacle. Therefore, for teams who master the ICS, they can choose to ride out-of-phase on the climbs too smooth out the delivery of power to the rear wheel and then adjust to either in-phase when slaloming through the trees, with the stoker adjusting their crank position as needed based on the captain calling out obstacles and/or anticipating the appropriate crank position when negotiating obstacles.

Last edited by TandemGeek; 07-22-05 at 05:38 AM.
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Old 07-22-05, 09:31 AM   #21
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Quote:
Originally Posted by TandemGeek
Absolutely not... with one exception; daVinci's ICS.

Let me elaborate: If your off-road riding is limited to forest service roads and non-technical trails where you will not encounter any obstacles, it's probably not a big deal. However, for those who ride technical terrain and single-track, having the cranks out of phase presents some serious safety concerns for the Stoker's feet. While there are some teams who will put the cranks one or two teeth out of phase, once you get beyond that you run a very high risk of driving your stoker's feet into logs, rocks, trees and other obstacles commonly found on the trail. While it's possible that a captain "could" have enough mental capacity to constantly remind himself of his stoker's pedal positions and remind himself to position the cranks to keep their feet clear of obstacles, my personal view is that anyone who has learned to ride single track on a personal bike will fall victim to "instinctive habits" that even make remembering in-phase crank positioning a challenge with regard modifying your ratcheting technique when grinding over logs, dropping over berms, or delaying the restart of pedalling when cornering around trees or stumps, anyone of which could slam a stoker's foot into the obstacle.
Exactlly what i was thinking,,,,,
I ride my tandem on the same trails I ride my single bikes(sometimes even full suspensions,,,even my Nicolai M-pire with 9" of travel,,I just go much slower at least sometimes) some of them are pretty dificult even on a single bike, most of the time extremlly Narrow singletracks (2 feet wide at most) and for sure Logs, rocks, branches and even some jumps are a dailly occurance (a.k.a. many times X ride...)

i was just wondering if anybody use their bike for agresive dirt riding, but i'm also fully aware of the risk involve so i just want to clarified...

actually on a related topic, the Off face cranks is pretty similar to a internal conbustion engine and the many diferent configurations that can be achive, even if on a bicycle the pedaling forces are some how rounder a "power stroke" still kind of present at least at slow crank rotations or when high power output is require...
a few Inline twin motorcycles use a 90 deggre crank configuration, not to mension the V-twins with the diferent deggres, (from 52 to almost 70 in some cases, or the "Boxer" type with a 180 deggre (also Porche and subaru) were the torque delivery is sustancial and the vibration is some how keep to a minimum,,oviuslly is a big diference in between 90 revolutions and 9000 RPm but still a interesting comparation.
Quote:

daVinci's independent coasting system -- which permits the captain and stoker to stop pedalling or to back-pedal independent of each other -- puts the burden of proper crank placement on the stoker AND has the added benefit of allowing the stoker's pedal to "give" and move backward if it does strike an obstacle. Therefore, for teams who master the ICS, they can choose to ride out-of-phase on the climbs too smooth out the delivery of power to the rear wheel and then adjust to either in-phase when slaloming through the trees, with the stoker adjusting their crank position as needed based on the captain calling out obstacles and/or anticipating the appropriate crank position when negotiating obstacles.
Well I have my issues with that sistem too...I be to scare for my partner to not see a obstacle,,hell sometimes even the captain can not see them in time...

in fact I'm trying to develope some kind of "Clutch" that will let me engage the freewheels to become "FiX" with minimal work (Ideally a lever at the bars) so i can attemp dificult sections ussing the cranks in face and on the easy stuff let them act independentlly....
I already have some "dual porpuse" suntour freewhels that provide that dutty ussing engagement "set screws"(little rods that lock the outside body in place in relationship to the main body) but the solution is crude and somehow chessy...

will see i being know to come up with concepts like that before, in fact is what i do for a living but more than anything i just love the challenge and the adventure of discovery..also if anybody is aware of a sistem that provides this "Locking function" will be nice to see how they acomplish it ...(maybe subject for another topic)

thanks as ussual for the elaborate and competent answers
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Old 07-22-05, 04:02 PM   #22
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Definitely not being an off-roadie, we have tested Mt. bike tandems off-road (single track, not forest trails), and agree 100% that pedaling OOP would be a problem.
The daVinci system is the closest to being able to pedal OOP (when desired) off-road; stoker would have to be very aware, or see, the line the captain is picking, which could be rather difficult.
OOP, basically, is a roadie option.

Pedal on TWOgether!
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Old 07-25-05, 12:04 PM   #23
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I'm a pretty new Greenspeed GTT rider. My wife and I started in phase, but then switched to 90 OOP. We like riding OOP much better. It's a smoother ride, and balancing the load on the rear wheel makes shifting much easier.

I can imagine how OOP could be a problem on an upright bike, but it is wonderful on a recumbent trike.!
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Old 07-27-05, 07:36 PM   #24
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Just tried 90 degrees OOP today for the first time- as captain I really liked it- much smoother and better climbing in the saddle- noticeably less frame flex. We do not climb out of the saddle at the same time but when I stood again less frame wobble. Starting does take a bit more coordination. By the way Zonztzndems screwdriver sugestion worked very well- no need to mess with the eccentric.
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Old 07-27-05, 09:38 PM   #25
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Quote:
Originally Posted by lmzimmer
By the way Zonztzndems screwdriver sugestion worked very well- no need to mess with the eccentric.
For those who opt to use this method of chain removal let me recommend that you run a little extra slack in your timing chain such that you can derail the chain by pulling it away from the front timing ring as you rotate the cranks, i.e., it can be removed and reinstalled by hand and without the aid of a lever.

If the chain is too tight and a lever is used you stand a good chance of "tweaking" a chain link or nicking the teeth on your chain rings. Nicking the rings isn't a big deal but weakening a rivet on your chain can come back and bite you out on the road where you may or may not have all the tools you need to splice in a link if your timing chain comes apart.

FWIW: We run both our road and off-road tandems with enough slack (3/4") to do this "by-hand" removal of the timing chains and have never thrown the timing chain as a result of carrying this extra slack. However, when time is not of the essense and when doing periodic bike maintenance I will usually loosen the eccentric to remove the timing chains OR -- noting that we have self-extracting crank axle bolts on our road tandems -- I'll simply remove the front crank to get the chain off. In any event, the point is to make sure that you don't forget to service your eccentric now and again if you do find that you can remove your timing chain without loosening the eccentric.
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