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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 05-10-11, 07:45 AM   #1
trayraynor
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Pedal Pushing Puzzle

I am planning to replace the clipless pedals on the Stoker crankset. It currently has a set of Shimano PD-550. However, as I was pulling the Stoker pedals I noticed that both crank arms had pedals marked with "R" - - scratching my head I inspected the Captain's crank arms and found a "L" pedal on the Right crank arm, and a "R" pedal on the Left crank arm.

Being new to tandeming, is it normal that out of four pedals, rather than having two "R" pedals, and two "L" pedals, that one would have three "R" and only one "L" ??

If this is common setup, is it easy to find a new pair of "R" pedals for the Stoker position?

Last edited by trayraynor; 05-10-11 at 08:15 AM. Reason: Stated incorrect pedal orientation
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Old 05-10-11, 08:10 AM   #2
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Originally Posted by trayraynor View Post
If this is common setup, is it easy to find a new pair of "R" pedals for the Stoker position?
This is wrong. A tandem-specific crankset would have "R"s on the right and "L"s on the left.

In your description, the first paragraph indicates that there are 2 "R"s in back and 2 "L"s in front; but the second paragraph says that there are 3 "R"s and 1 "L". I am going to assume that the 2nd paragraph is correct, since it is consistent with the builder having used single-bike crankarms rather than a tandem-specific crankset. The stoker drive-side is correct, since they are the same for both tandems and singles. However, the builder of your tandem used single-bike drive-side crankarms for the timing side, resulting in reverse threads. The captain's right crankarm is a single-bike left crankarm installed on the right side.

I know of one local builder who converts single-bike cranks to tandem cranks by reaming out the pedal threads and installing a heli-coil with the correct threading. Maybe you can find a builder in your area that can do the same.

Last edited by swc7916; 05-10-11 at 08:24 AM.
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Old 05-10-11, 08:14 AM   #3
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Hi swc7916. Sorry for the confusion. You are correct, I have two "R" pedals in the back and a "L" and "R" on the front. Based upon your assessment, if I'm to replace the Stoker's pedals, it looks like I'll need to purchase two pair in order to get to "R" for the back; is that correct?
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Old 05-10-11, 08:33 AM   #4
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Unfortunately, yes. An "L" pedal on the right side (and an "R" pedal on the left side) will tend to unscrew itself under use, that's why they're threaded for a specific side. I have no experience with pedals installed on the wrong side, so take my advice with for what it's worth - but if you're not going to have the crankarms re-threaded, I would make sure that they're good and tight and check them frequently.
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Old 05-10-11, 08:35 AM   #5
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Here are photos to show you the current crank arm arrangement.
Attached Images
File Type: jpg P1030490.jpg (80.6 KB, 11 views)
File Type: jpg P1030491.jpg (78.8 KB, 12 views)
File Type: jpg P1030488.jpg (77.2 KB, 11 views)
File Type: jpg P1030489.jpg (81.1 KB, 13 views)
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Old 05-10-11, 08:55 AM   #6
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It certainly looks normal, however you can't tell pedal threading from the photos. What you apparently have is a single-bike crankset flipped around on the front and a single-bike drive-side crankarm on the left in the rear.
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Old 05-10-11, 09:09 PM   #7
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That's the way I set up my tandem. Since I like Campagnolo stuff, I used Record cranks for the entire drivetrain. So instead of tapping a larger hole [and possibly weaking it] and installing a correct helicoil, I got right side pedal spindles. Never had an issue and I think personally that the reverse threading is overrated. Bolts that are tight do not come loose [except for certain applications but none for bikes]. There's always locktite if you really are worried.

My biggest issue for making the timing cranks work, was installing the small ring on the large ring side [and make it look normal].
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Old 05-11-11, 06:12 AM   #8
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That's the way I set up my tandem. Since I like Campagnolo stuff, I used Record cranks for the entire drivetrain. So instead of tapping a larger hole [and possibly weaking it] and installing a correct helicoil, I got right side pedal spindles. Never had an issue and I think personally that the reverse threading is overrated. Bolts that are tight do not come loose [except for certain applications but none for bikes]. There's always locktite if you really are worried.

My biggest issue for making the timing cranks work, was installing the small ring on the large ring side [and make it look normal].
I agree. Have a Mountain Tandem set up this way and have never had any problems with the pedals loosing up.
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Old 05-11-11, 07:56 AM   #9
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Okay, I do appreciate the feedback. Rather than going through the helicoil route, I will purchase two pair of platform pedals, this way I'll have two "R" threaded pieces to use on the Stoker position. Thanks!
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Old 05-11-11, 10:01 AM   #10
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I think personally that the reverse threading is overrated. Bolts that are tight do not come loose
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I agree. Have a Mountain Tandem set up this way and have never had any problems with the pedals loosing up.
It's quite possible that if the pedal is adequately lubricated and the spindle is screwed in tight that the rotational forces are not high enough to unscrew the pedal, but are you refuting the notion that the rotational forces of a pedal on the "wrong" side are in a direction to unscrew the pedal? Are you also disagreeing with idea that if you're going to go this way that you should make sure that the pedals are tight and to check them once in a while?

I frequently read these forums, but every once in a while I get stupid and post something, forgetting that there's always someone out there to tell you that you don't know what you're talking about. Hopefully I'm smarter now and can refrain from posting ever again.
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Old 05-11-11, 12:20 PM   #11
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Originally Posted by swc7916 View Post
It's quite possible that if the pedal is adequately lubricated and the spindle is screwed in tight that the rotational forces are not high enough to unscrew the pedal, but are you refuting the notion that the rotational forces of a pedal on the "wrong" side are in a direction to unscrew the pedal? Are you also disagreeing with idea that if you're going to go this way that you should make sure that the pedals are tight and to check them once in a while?

I frequently read these forums, but every once in a while I get stupid and post something, forgetting that there's always someone out there to tell you that you don't know what you're talking about. Hopefully I'm smarter now and can refrain from posting ever again.
I'm not saying not to check the pedals I check the pedals on all my bikes form time to time. However I have never found the pedals loose on our mountain tandem.
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Old 05-16-11, 11:51 PM   #12
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Honestly, I have not checked the Captains pedals in 3 years. I have changed the stokers cranks from 175mm to 170mm when my daughter and I trained for the one day Seattle to Portland ride last summer. I did swap the pedals from the stoker cranks and they were tight coming out and they are tight now. No locktite was used.

I would always recommend that everything is tight when you are putting together a bike or any other project you may be doing. Factory specs are there for a reason. I have not lost any sleep about the pedals [properly torqued].

I am not an engineer, just an auto mechanic. I know one manufacture [Chrysler?] that had reverse theads many years ago with their lug nuts. They stopped using them. As far as I know, the only nuts/bolts that fall off cars are the ones that never got torqued correctly. Don't ask me how I know that [trade secrets].
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