Bike Smith can shorten cranks for you but not all cranks can be shortened and you need to have up to 22mm between the center of the existing pedal hole and the new one to shorten them. He will sell you cranks that he has shortened. I recently had him shorten a crank set for my tandem from 175 to 140. I provided the crank driveside arms…a Truvativ Hussefelt…and he did the work. It was quick and relatively cheap, around $80 with shipping. I chose the Hussefelt because it is a very thick crank from the spider to the end of the arm are you can see below. I don’t pictures of the have the finished right now but I’ll take one of the tandem and post it later.





I have done several of my own as a test to see if it would work and because it did work. But you do have to choose cranks that are thick and you need a fair amount of length. A 185 to 160 would probably work. I was going from a 175 to a 140. Be warned that to do the work at home involves a lot of work and it’s easy to screw up. I start with 5 drills to step up the hole size to the 1/2” hole needed for the taps.



For me, one of the most difficult parts is to find, and mark, the center of the pilot hole.



I use a vise to clamp the crank in place but I also make sure the vise is clamped to the drill press. You don’t want the last bit of the drill going through the metal to grab it and spin it around. Ask me how I know.



Centering the drill as you step up the drill size can also be difficult. The pilot hole is easy but I have to move the deck on the drill press to install the next larger (and longer) drill so there’s a bit of fiddling. I only have a small press without much of a throw on the drill shaft.




Tapping is another place where it’s easy to make errors. A few of my efforts have been not as good as others because the tap went in slightly crooked.



The final bit, for which I don’t have pictures, is cutting off the old threads. I tried a hand grinder. Don’t do that unless you have a really steady hand. I usually end up with a hacksaw and/or a Drimel and a lot of file work. It’s almost easier to drill and tap than to cut off the crank arm. Frankly, it’s easier, cheaper, and the results are better if you just send or buy cranks from Bikesmith.

By the way, my wife is only 5’ tall. The reason for shortening the cranks came out of my about ruining her knees on a tandem ride in Nebraska. We did 50 miles on the first day with her using a 175mm stoker crank. She was in agony at the end of the first day. We had done 35 to 40 mile days but nothing quite as long. We were able to do the second day but just. I found this article by Bikesmith about stokers and the problems they have with longer arms and started to experiment.

I then stated thinking about her other bikes and decided to change cranks on them too. Recently we went on a ride with a new bike with short cranks and she decided to try and climb a short hill standing up. She never stands to climb. She was shocked that she could actually do it and that it felt good! That’s a 140mm crank in comparison to a 165mm crank that she uses often. I have made cranks for all her bikes now.