Puch three piece crank

Chris--Cincinnati /

Alright, I got a three piece crank for my puch. I have it installed, but I can't seem to get the pedal arms to line up correctly on the crank shaft. Does it matter which side you put the pedal arms on the crank shaft? It makes it kinda hard to pedal, if they aren't lined up even. Any ideas? Thanks!

Re: Puch three piece crank

Ron Brown /

Chris,

If it uses cotter pins, install them from opposite sides (one with nut up, one with nut down).

Ron

Re: Puch three piece crank

Chris--Cincinnati /

Sweet! So, one side will have the threads sticking out, and the other will have the smooth end sticking out? Good shot Ron!

Re: Puch three piece crank

Ron Brown /

Chris,

I just had to do this. : )

This is from my 10/22 post that sent you into the yard to eat worms:

"Some rules. Cotter pins are installed with the threads in opposite directions. Cotter pins must have perfectly smooth flats, if you can't clean them up with a file, get new ones. Most bicycle shops should have them. With the left side pedal pointed forward, the right side cotter pin should have the thread pointed down, the left side, thread up."

This is a little more specific because it puts the heavyest loads on the widest part of the cotter pin. I also like to re-tighten the cotter pins after they have had a few minutes to seat or after the first ride.

Ron

Re: Puch three piece crank

Well, that is pretty much all that I needed to know! Thanks Ron! Your the man. I have never eaten worms...on purpose. :)

Re: Puch three piece crank

by cotter pins, do you mean the ones that are round, with a bevel down it's length? If so, the bolt holds them in place, but you need to pound them in form the non-threaded end, and put the bolt on to hold them. The taper and the surface area is what holds it together. If you just tighten them thru, it will strip the threads and your crank arm will wobble worse and worse untill there's a groove in the pin. It's very important that if you get a new pin, try to get a pair that match and are the same diameter and bevel. Otherwise it still won't be straight.

I had hell with an old english bicicle I got, because it used a non-standard (huge) pin. I went thru several crank arm pins untill I found one that came close to fitting. I got it close enough and sold the damn thing to a forign exchange student.

Re: Puch three piece crank

Ron Brown /

I spent the formative years of my mechanical obsession building english bikes out of junk. They all used 3 piece cranks with cotter pins, I don't think the English have discovered 1 piece cranks yet!

Do not hammer the cotter pin in! Once the flat on the pin is notched from hammering, there is no way to tighten it. Make sure the tapered flat is not notched from previous use, that the crank and/or spindle are not worn to a bad fit by running with a loose cotter pin. Tighten the pin with a wrench while wiggling the crank to align it. Re-tighten after riding a little.

There are a couple more posts on here with more detail.

Ron

Re: Puch three piece crank

Crisis--cincinnati /

I got them on fine! I did use a hammer to get them in, but it worked out well. Thanks for everyone's help!

« Go to Topics — end of thread

Want to post in this forum? We'd love to have you join the discussion, but first:

Login or Create Account