I just got a new Tandem, and I put my spd clipless pedals on, but, is it my imagination, or is the front crankset backwards from normal because the chain is on the left side********** Will I be able to clip in, or is everything off now???

A LSD crank should have the pedals threaded backwards. Think about it a moment and it will make sense.

Tandem cranksets are threaded differently so that the pedals will thread into the crank and not unthread themselves. If you were to take a crank off of a single bike and try to install it backward on the forward position of a tandem it won't work satisfactorily.

I must be missing something. I just took 2 pairs of pedals out of the box. Put the 2 lefts on the left side & the 2 rights on the right side. Worked just fine.

Well, I understand why the pedals should be backward on the front cranks: it's cause the chain is on the left side, not the right side as on every single bike. SO it is flipped around so that the pedals don't unscrew while riding.

But will my clip in pedals still work now???

Here's the deal. There are two types of tandem crank systems:
So, given this knowledge, there are three ways to create a crankset for a tandem, well actually four....

1. You combine two single bike cranksets to create a same-side drive that has only two chain rings for the drive chain.

2. You buy a tandem-specific cross-over crankset that has the correct right and left-hand threading for the cranks that belong on the respective front, rear, right, and left-hand sides of the tandem.

3. You get a hold of three one-piece or square-taper spindle, single bike cranksets with the same length of crank arms and use two of the drive-side cranks on the wrong side of the bike with a lone, single left-hand crank arm mounted to the right front of the tandem. This is where it gets interesting as there are two ways to deal with the three sets of incorrectly threaded crank arms:
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Bottom Line: If what you're conveying is that you have discovered the left-side cranks are right hand threaded, then you've got a "cheap and easy" cross over crankset on your new, used tandem. As for using SPD pedals backwards, I don't think I've ever seen any where it should work: the left and right hand pedal engagment and release mechanisms are asymetrical.

Wow, thanks Tandem Geek. Great post. I often see long posts that don't give a direct answer, and I often see short answers that lack any details or useful info. But your post is a how-to-guide for answering questions. Give the info, and a simple answer for the doofus who asked the question.

Thanks again!

I just took off my clipless pedals and re-attached platform ones. Oh well, I suppose it isn't necessary for me to have my bike shoes on when tandem riding. I'll just be doing short tours with the mrs for now.

We've set the bar down on teh gropund....

Huh?

Not SPDs, but Eggbeaters would work I think.

Have you tried riding it backwards********************? Sorry, I just had to say it. Good Luck, Tim

I have a inexpensive child stoker kit with the same issue. I used Eggbeaters for my child and they work fine.

I already have SPD, so I think I'l just use my mtb shoes, but with the patch bit instead of the cleat, and keep platform pedals on the tandem. It's only a beginner tandem anyway.

How about disassembling the pedals, and then re-assembling them so that the directionality of the cleats is maintained?

It seems to me that only the pedal-spindle to crank thread is left or right hand, that the threads on the tips of the spindle are typically right-handed. The pedal itself doesn't know what thread is on the crank end of the spindle, does it?

Hmmmm, I'll take a look at them tomorrow and see if that's viable. Good idea.

Park Tools' site says

"The threads of the adjusting cone and locknut are right hand-threaded on both left and right pedals."

When I wrote 'the pedal doesn't know what the thread is at the crank', what I meant was that the part of the pedal which contacts the cleat should be flippable from one side to the other.

It will be interesting to hear what does/doesn't work.

Let me truncate this discussion and make a simple observation about bicycles and the concepts of "compatible and incompatible":

1. Right-hand and left hand pedals, along with just about anything else that rotates about an axis on a bicycle, often times have right-handed and left-handed threading to mitigate the problems that occur with precession. In some cases, you must take time to fully understand how each component on a bike that you plan to modify actually works before making your modification. Just because something may "seem to fit" does not necessarily mean that it was designed to work that way. Pedal axles can fall into this category as different parts of the axle may have different threading depending on how precession acts on them. In fact, if you ever overhaul a set of Campy shifters to replace the hood or worn shift disc and springs, you'll find the internal retention bolts on the right hand shifter are left-hand threaded, whereas those on the left-hand shifter are right-hand threaded.

2. There are, in fact, many things on bicycles that aren't supposed to work but that do... go figure. Steerer tubes that are too long or too short have been "made to work", certain Campagnolo and Shimano drivetrain and shifter components can be intermixed, rear wheels often times can be "made to fit" between rear drop-outs that are too wide or too narrow, tires that are either too wide or too narrow for rims will still fit on those rims and, yes, some folks have successfully put cranks on bicycles backwards and not had any problems with pedals coming unscrewed. However, the amount of variability that exists with regard to individual success with these scenarios is wide and the implications of falling outside the margin for success can impose anything from inconvenience (losing a pedal and riding home with three legs) to injury (hurting yourself when a pedal comes off while standing on the pedals under a heavy pedal load). Do your homework and know the pros, cons, risks and rewards.

3. I don't claim to have all the answers; I've just made a lot of mistakes and otherwise learned many things the hard (and expensive) way. By all means, push back if I get off base.

And I've been afraid the last two days that if I take the pedals apart, I won't be able to get 'em back together.

So long as you use the proper tools and follow the guidelines at the Park Tool site, you'll do just fine sticking to the axles: just do your work on a clear, clean and well-lit surface and put some white paper towels down so that any little parts that fall out -- like loose bearings and small washers -- will stick where they drop, be easy to see, and won't take off across the room.

Just remember, if when you're disassembling something it seems like it's stuck, make sure you've got the threading figured out before you start getting creative or bending wrenches: 9/10 out of 10, if the wrench won't turn on a rotating part it's because what you're cranking on is reverse threaded. "Wacking" things with a plastic mallet or applying massive torque -- unless specified in a repair manual -- is a sure sign that you're headed for trouble. Likewise, things that unscrew smoothly should screw back together smoothly. If you encounter resistance STOP! There's a good chance you've got it cross threaded. If you're mixing and matching parts of unknown pedigree and the threading does seem right, check it with a thread gauge.

As for complexity, it's only as you get into the spring release mechanisms on pedals, such as those in the Campy ProFits that you can find yourself cussing up a storm and searching for compression clamps. Again, if you use a good shop manual or on-line manuals, the instructions should help keep you clear of trouble.

Anecodotal account of "Precesion" at worK:

I'm not sure if this is Murphy's Law or just karma at work, but a funny thing happen while doing a shake down ride last evening on a recently acquired, second hand Calfee single bike that had a bottom bracket with Italian threading. It's probably been 15 years since I had a bike with an Italian threaded bottom bracket.

Whilst out on my ride and about 12 miles from home I noticed the front derailleur wouldn't shift the chain into the big chain ring. A quick check confirmed the cable didn't slip in the pinch bolt, the shifter was working fine, the cable was not bound-up, and the derailleur and derailleur stops were where they should have been. Hmmmm. That's odd. Further inspection on a hunch revealed that the bottom bracket cups and cartridge bearing spindle assembly had backed itself out of the bottom bracket shell as a unit: not at all an uncommon problem with Italian threaded bottom brackets. Not having a crank puller or Campy bottom bracket tool in my pocket, it became a challenge to see if I could get home before I was REALLY in trouble. Thankfully, I made it but by the time I hit the drive way the left-hand crank was rubbing against the left side of the bottom bracket shell and, if there was any doubt, carbon is tougher than aluminum.

Note to self: Remember to use Loctite 242 before torquing the fixing cup on Italian threaded bottom brackets.

That was the reason for "Swiss" threading in days of yore, with the lockring and left-side cup threaded left-handed, and the right-side cup right-handed, for bottom brackets, wasn't it?

Almost, but not quite the way that you described: flip around your threading and then you've got it.I'm not exactly sure of the geneology of the various different bicycle bottom bracket design standards, I just know that there are a lot of different variations and the pursuit of the "perfect" bottom bracket design continues today with the different variations of Octalink, ISIS, and now oversized ISIS, never mind other nuances such as the different ISO vs. JIS square taper standards.

The current "English" standard, aka B.S.A., B.S.C, Britsh, ISO was introduced back in the 20's by B.S.A. and it remains the most common, particulary in the US and, well, Britian. English BB's for road bikes are all 68mm wide and have a diameter of 1.370" with 24 threads per inch (TPI) and the right hand "fixing cup" is left-hand (reverse) threaded. This is the opposite of how pedals are threaded, but for the same reason: to ensure that precession works to tighten the component instead of loosening it.

Italian bottom brackets are all 70mm wide and have a diameter of 36mm with 24 threads per inch (TPI) and the right hand "fixing cup" is right-hand threaded. I don't know when or why the Italian standard was introduced but I'm sure someone could probably Google it and find out. The only thing nice about Italian threaded bottom brackets is that if you strip out your English-threaded BB you can have them re-tapped to the slightly larger Italian threading and use a 68mm BB cartridge made by a company that also offers its BBs in the Italian threading so that the cups are interchangeable. Other than that, Italian BBs just mean you need to pay attention to your bottom bracket after any maintenance to be sure that you've gotten it tightened enough to keep it from coming out as you ride.

French and Swiss both came into use in late 60's and disappeared in the 80's as they were pretty much failed standards (again, not at all uncommon with bottom bracket designs). They both use a width of 68mm and had a diameter of 35mm with 1.0mm threading. The difference was that the French used right-hand threading on both right and left bottom bracket cups (which meant they too would come unscrewed, just like the Italian standard) whereas the Swiss adopted the English/ISO approach of using a left-hand threaded fixing cup on the right side of the bike.

Pedal threading is the opposite of bottom bracket threading because the rotation of the axle relative to the crank and bottom bracket is reversed. Likewise, as you start heading into a pedal the direction of the threading and rotational forces flip-flops as well. If all the stars, moons, and threads are properly aligned, everything stays together. Once you start flipping things meant for right to left things can start to come undone.

Wow, lots of discussions about pedal threading lately (here & here). Very insightful comments & interesting history from everyone, but was it ever determined for sure that becnal's captain cranks are backwards? If the pedal with an "L" on the spindle installs into the left side of the bike (reverse threaded) and the pedal with an "R" on the spindle installs onto the right side of the bike (normally threaded), regardless of chainring location, then everything is as it should be. SPD shoes will clip/unclip fine. I just hate to have becnal stuck with platform pedals, or even worse swapping spindles on SPD pedals (I've done this - kind of a pain) for no reason ...

Good luck!

winbert

If somehow Becnals cranks are really threaded 'the wrong way round', there's a fairly easy solution that doesn't involve disassembling pedals. Find a set of screw taps (left and right) with the proper measurements for pedal spindles. Then cut a new thread in both cranks (now the proper way around) and mount the pedals. This is a solution an engineer whom I know and trust uses quite regularly. He claims there is way enough "meat" (as we call this in Dutch) in a crankset to 'countercut' these threads and still properly hold the pedal in place. If you feel the need, apply some Loctite when mounting the pedals.

Just my 2 cents worth.