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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 07-21-08, 09:30 AM   #1
72andsunny
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Out of phase--the first 100 miles

After a little experimenting, we have settled on me (the captain) 90 degrees minus one click ahead of the stoker.

The stoker found starting to be a little harsh at a full 90 degrees behind (something about me stopping the cranks at the bottom of my stroke). Overall, I would say we have picked up 1 to 2 MPH on the flats, and we're taking most hills in the middle chain ring (instead of the granny gear). We probably have not gotten any better at climbing, but I figure since we're out of phase, I am less likely to be doing all the work...which prompts me to work a little harder. Once the stoker gets tired, going uphill becomes incredibly jerky; the rest of the time things are super smooth.

In other news, I figured out why I could not fit four of our new water bottles (which appeared to be the same size as the old water bottles) on the bike: I seem to have installed the down tube upside down (hence no clearance for the stoker's top bottle). I am a genius.

P.S. If you can't stand the taste of plastic in your water, Camelbak bottles are highly recommended.
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Old 07-21-08, 11:26 AM   #2
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Another happy OOPer?!!
We've been pedaling as OOPers for 200,000+ miles . . . for us it works great with full 90 degrees out. But whatever works for the team is the way you got to go.
Stoker can slightly back pedal at a stop to get foot in right position for pilot.
OOP provides a continuous power stroke; less flex in frame; less wear on BBs . . . and can confuse the heck out of somebody that's drafting you!
Glad it worked out OK for the 72andsunny duo!
Pedal on (OOP of course)!
Rudy and Kay/zonatandem
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Old 07-21-08, 11:34 AM   #3
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In other news, I figured out why I could not fit four of our new water bottles (which appeared to be the same size as the old water bottles) on the bike: I seem to have installed the down tube upside down (hence no clearance for the stoker's top bottle). I am a genius.
Jeez, looking at the picture, I see I have the top tube backwards as well (Since we put on the disc, we're not using the brake cable braze on anymore...but I'm pretty sure it shouldn't be there).

Oh well, going on the Santana San Juan Islands tour in 3 weeks, so I'll get a chance to fix everything. Is any one else planning on going? We are hoping to not be the only team without kids. (I asked to borrow my 4 year old nephew to tow around, but he was not interested).
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Old 07-21-08, 02:15 PM   #4
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Another happy OOPer?!!
... ...
Pedal on (OOP of course)!
Rudy and Kay/zonatandem
And all the elements in the drivetrain (chainwheels,chains,cogs) will be glad too !
Since OOP means a lower peak load and a more smooth force (torque) distribution per crank angle.
(Why do you think (multicylinder) car- and motorcycle engines all have a crankshaft which 'off-phases' each cylinder at equidistance crankshaft angles?)
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Old 07-21-08, 03:20 PM   #5
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We rode 90 degrees OOP all last year, but have backed off to the captain leading by 45 degrees this year. It's much easier on Pam to start and stop, so she likes it much better, and I can tell that we still get some of the OOP advantage when climbing.

I'm convinced that we do climb better, especially on the steeper stuff we encounter. It doesn't matter whether we stay seated or stand, we're just smoother and never bottom out like we tend to do when riding in phase. I can't really tell, however, that it helps us in terms of speed.
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Old 07-21-08, 04:38 PM   #6
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Our activity has been pleasurable with the change in phase. ?I guess? I started out at around 150 out by mistake after a crash. Really wierd and hard when we came up to a curb but seemed to work well on the hill climb we did after our crash and the 5 miles to home on Wednesday. I then reviewed some thought on it and moved it to about 30 degrees and on a really flat ride this Sunday we found it to be really pleasurable. I will change it a bit more prior to our next ride and get it to 90 degrees - 1 click. (This would be 10 teeth out instead of 11 as I think the synch ring is 42+/-???) just checking???

The crash story follows:
We inadvertantly went out of phase with our vintage Burley after 7/16/08 crashing on a set of wicked railroad tracks. They had swept the roads in an industrial area and pushed dirty raod chiz around the tracks. Slicker that can be. (Forklit driver at site said we were 4th set of bikers in 2 days to go down) Luckily, my wife was not hurt to the point she was concerned enough to not get back on. She hit pretty hard on her elbow and knee. I believe I somewhat separated my shoulder and it is really sore. Some serious road rash on the left forearm, elbow, bicep, hip and my bionic replaced ankle. I took the hit on hip and collar bone area.

We are doing the Seattle Century this weekend, July 27, 2008. It is going to be a great time. I am doing alot more of my work on the bike and bought a truing stand and my wheels purr now. Shifters, deraileurs and linkage are next. Got the after ride tune up dowh now.
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Old 07-21-08, 05:10 PM   #7
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Interesting...

I'm new to tandeming and while I do understand the mechanical advantages of being OOP, is this what most experienced tandem-ers have set up on their bike? For the serious rider or tourer, is being OOP fairly common?Why don't tandem manufacturers set up the cranks OOP by default?

My local routes can be tailored with a lot of climbing so I'm now really curious about what my cranks can do if they were OOP.
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Old 07-21-08, 07:34 PM   #8
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Interesting...

I'm new to tandeming and while I do understand the mechanical advantages of being OOP, is this what most experienced tandem-ers have set up on their bike? For the serious rider or tourer, is being OOP fairly common?Why don't tandem manufacturers set up the cranks OOP by default?

My local routes can be tailored with a lot of climbing so I'm now really curious about what my cranks can do if they were OOP.
Do a search of this forum for OOP or Out of Phase and you'll find a lot of discussion. What it really boils down to is that it's a matter of preference. Most folks probably don't want to deal with the added hassle of riding OOP, because it does take some concentration and attention...especially on the part of the captain to keep the stoker from being in awkward positions coasting, starting, and stopping. For that reason, I personally recommend that new teams not even try it for a long time (if ever). There are enough things to learn about riding a tandem without throwing in the extra complication.

You see tandems coming from the factory in phase because that's the way most folks ride. Some say it just feels and looks better to be in phase...two riders working together. If you've ever seen a team riding 90 degrees OOP, it definitely looks like something is wrong.

For us, 90 degrees OOP was more than my stoker wanted to deal with, but 45 degrees is a nice compromise. It seems like we're able to climb a little smoother than we do when riding in phase. Probably not enough to be measurable in any way, but it's just a feeling for me. I don't think Pam notices it unless we stand.
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Old 07-22-08, 10:10 PM   #9
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And all the elements in the drivetrain (chainwheels,chains,cogs) will be glad too !
Since OOP means a lower peak load and a more smooth force (torque) distribution per crank angle.
(Why do you think (multicylinder) car- and motorcycle engines all have a crankshaft which 'off-phases' each cylinder at equidistance crankshaft angles?)
Hi, yes, but in an engine and on tandem while synchronized you would generally have more low end torque; And with the crankshaft or tandem cranks offset you would generally have more RPM or horse power. [smoother and less stress on parts] Has anyone tried a 180 degree set up? That would be with the captains right pedal on top and at the same time the stoker's left pedal would be on top.
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Old 07-23-08, 10:10 AM   #10
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Has anyone tried a 180 degree set up? That would be with the captains right pedal on top and at the same time the stoker's left pedal would be on top.
I can't see any benifit for seated pedaling, and that would play hell with standing, with the heavier rider throwing the bike the wrong way for lighter one...you try not to throw a tandem, but a little bit is inevitable. Also, consider what happens when the captain lowers his outside pedal for ground clearance on a tight corner! 90 dg. OOP, at least the stokers cranks are level.
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Old 07-23-08, 12:15 PM   #11
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Hi, yes, but in an engine and on tandem while synchronized you would generally have more low end torque; And with the crankshaft or tandem cranks offset you would generally have more RPM or horse power. [smoother and less stress on parts] Has anyone tried a 180 degree set up? That would be with the captains right pedal on top and at the same time the stoker's left pedal would be on top.
Why should anyone try a 180 degree offset:

First of all a 180 degree offset is of NOT out-of-phase WHATSOEVER since for a bicycle one complete cycle is 180 degrees so IF you off-phase to the max (theretically ideal) THEN you need a 90 degree offset.
Secondly there would be a collision of the toes of the stoker with the heel of the captain two times per revolution of the crank ! (to avoid this you'd require an extreme bracket-to-bracket size).

In an (four-stroke) engine by the way ONE complete cycle is a 720 degree so if you have a four cylinder engine at each 180 degrees of the crankshaft (180=720/4) one cylinder will be firing (but this is a bicycle/tandem forum so please don't try to find examples like 90 degrees two-cylinder-in-line-four-stroke-engines and so on...)

So if you don't like OOP then (ofcourse) go back to 0 degrees, but I was only trying to point out that max OOP (90 degrees) is THEORETICALLY ideal.
I think, however, that if scientific measurements would be done on this issue, it (the 90 OOP) also will be praktically better (measurable higher poweroutput)
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Old 07-23-08, 01:16 PM   #12
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We have been in phase, 90 out of phase captain leading and also 45 OOP for a little while . 45 OOP was too silly, felt like one leg was working more than the other. 90 OOP was OK, but after riding 300 km or so we went back to being in phase. We had ground clearance issues with speed bumps and curbs, it was too hard for me (captain) to instinctively remember where stoker's pedals are going to end up, and at times ended up in wrestling matches to be on the top of the stroke when starting up . The advantage of balancing the power did not seem significant enough. However I suspect there is a big mismatch in power output between captain and stoker which I do not care to investigate further.
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Old 07-23-08, 04:37 PM   #13
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'Bout 30 years ago did bash a pedal on a then novel speedbump on the border between US/Mexcico while OOP.
Since then pilot's awareness has increased!
It's been nice to see that more folks are at least giving OOP a try. Hey, if it's not for you, back to plan 'A"!
Pedal on (OOP-4-Us)!
Rudy and Kay/zonatandem
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Old 07-24-08, 12:06 AM   #14
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Just asking?

Hi, I was just asking if someone has done the 180 degree thing; I wouldn't do it and we are happy pedaling in phase. You brought up some good points on how it would not be good to do it.
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Old 07-24-08, 06:41 AM   #15
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45 OOP was too silly, felt like one leg was working more than the other.
I don't understand that observation. Can you elaborate?
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Old 07-24-08, 10:01 AM   #16
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I don't understand that observation. Can you elaborate?

Can't realy explain it either, but it felt very odd, unbalanced pushing on the pedals, have you tried it? Maybe my stoker does not push with equal strength with both legs, she has a bad knee which she might be protecting, and at 45 degrees it might be more noticible, since she pedals into my stroke. Just thought of this, I'll check, but perhaps you can tell me if you experience this oddity.
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Old 07-24-08, 10:24 AM   #17
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45 OOP was too silly, felt like one leg was working more than the other.
Hmmm. I'm guessing it must have been something to do with your technique. We're currently riding 45 OOP and it's generally a pretty smooth stroke for us. I will admit, however, that every time we've switched from in phase to OOP, the first ride has been a little on the wiggley side until we figure out how to get our strokes smoothed out.

As I said above...OOP isn't for everyone, and the only real measurable advantage we get from it is on a standing climb (which we do quite often here in the Ozarks) and some of the low-gear seated climbs.
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Old 07-24-08, 02:32 PM   #18
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Last night after work we were out for a ride after work and half way through this thread popped up in my head. So I pulled over and changed the cranks to OOP getting my hands extremely greasy in the process. Starting out was not good as my wife yelped when I pushed down on the crank. Once we got going it felt really weird. Smooth in a way but I could feel impulses coming from the back through my pedals. We tried to stand for a moment and that did not work at all. So after a few miles I switched back to IP which is much better for us. We have been riding IP for 25 years so we have trained ourselves well to do it. I suppose if you ride OOP over a long period it would work well and IP would feel weird.
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Old 07-24-08, 03:37 PM   #19
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not a good idea on a mtn tandem

I would not recommend this for mountain bike tandems i was just involved in a serious crash because of out of phase cranks. i had lent the bike to a friend and the timing chain fell off while he had it. not knowing any better he didn't think to check the phasing when he reinstalled it, nor did he mention it to me. well i hit a rock with the rear pedal on a tight downhill section which abruptly brought the bike to an almost standstill. my stoker and i slammed our knees into the handlebars. (tandems don't flip) i'll let you know the MRI results next week. Granted i was unaware of the phasing issue i would still prefer to err on the side of caution when it comes to mtn tandems.
my stoker? she got 6 stiches in her knee.
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Old 07-25-08, 06:30 AM   #20
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...hit a rock with the rear pedal on a tight downhill section which abruptly brought the bike to an almost standstill. my stoker and i slammed our knees into the handlebars
Yeouch!

Just curious, how much out of phase?
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Old 07-25-08, 08:24 AM   #21
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it was almost 90degrees oop. the rear crank was in about the 5:00 o clock position angled forward. it hit hard enough to bend the crankarm which will make a nice paperweight / conversation piece in it's next life.
I was thinking about the DaVinci independent drive system but without constant communication would the stoker know the ideal pedal position (crank arm angle) when negotiating technical terrain since they are riding blind
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Old 07-25-08, 05:30 PM   #22
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Agree, we do not recommend OOP for technical off-road riding.
Road, dirt paths are OK.
With the daVinci, stoker would have to be constantly told about terrain up ahead so she could have her pedals in position for the technical stuff. But due to daV not using chainrings (they use cogs) you do get some x-tra clearance there, but not with the pedals.
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