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Align 2 bikes exactly side by side?

Help! I need to align the pedal systems of two bikes almost exactly side by side. The two crank sets are joined at the inside pedals. 

Can anybody think of a relatively easy way of aligning the bottom brackets along the (almost) exact same axis? Note, it's just the cranks I'm concerned with, I'll be chopping off the remaining bike parts later.

Thanks!


**********UPDATE********
I think I've done it.

 




 

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I suggest make a jig. Figure out how far apart the bike have to be. Take your measurement from the upper tub on both frames. Then complacently pull the bikes apart so all you have is the frame. Cut boards the length you want the bikes to be apart and secure them horizontally to a flat level surface. Make sure they are square to each other and evenly spaced. Then take a couple of boards and secure them vertically outside of the horizontal supports spacing them the with of the frame tubing. Now you can drop the frames into place and know they are spaced correctly.

Now you can take a large framing square and clamp it to the board so it's standing strait up. This gives you a good reference point for sliding the frames forward and back on the jig to try and get the crank housings aligned. Also have a spacer handy to make sure the lower tube of the frame near the crank is also spaced properly.

Once everything is aligned you can clamp the frames to the jig and go about securing them together however you like. Then you can rebuild the cranks and figure out how to attach the pedals together. Likely you will have to have a flexible joint. Chances are the length of the pedal connection arms may be different. Also the holes for the pedals to attach to the arms may not be square with the arms. The arms may not be square to the frame. Not much you can do about that other that account for that inaccuracy buy leaving the pedal linkage flexible.

The way you have it connected now will not work. That outer band of the pedal starts wider close to the bike and narrows a bit as it moves outward. It would be better to secure the pedals together along the top and bottom of the pedals.
caarntedd1 year ago
Go to Instructables>Featured>All Channels>Bikes. Heaps of bicycle info.
iceng1 year ago
Different weighted riders or worse slightly different rear tire pressures
will cause a huge workload on the co-joined peddlers as one or both tires have to slide !!!!!

A
Burf1 year ago
Draw a straight line longer than the anticipated outside distance of the two cranks when assembled. Set the frames, side by side, perpendicular to and above the line. Plumb each frame from the center of the crank to the line.
The cranks are now in alignment, securely fasten the frames together and you're all set.
Burf Burf1 year ago
I forgot to mention you should block the frames up so the center of each crank is the same distance above the line.
Vyger1 year ago
You need to connect the 2 hubs with a common axle. A bar that goes across and rotates both together. You don't need to have the pedals connected , in fact they could be staggered, it doesn't matter because the rotation would be from the axle. Exactly how to do it will depend on your skills and what is available. The ideal thing would be to take the cranks off and replace the part that runs through the hubs with a single rod, then attach the cranks to it.