Cycling and bicycle discussion forums. 
   Click here to join our community Log in to access your Control Panel  


Go Back   > >

Bicycle Mechanics Broken bottom bracket? Tacoed wheel? If you're having problems with your bicycle, or just need help fixing a flat, drop in here for the latest on bicycle mechanics & bicycle maintenance.

User Tag List

Reply
 
Thread Tools Search this Thread
Old 02-16-10, 03:22 AM   #1
sevenhills
Senior Member
Thread Starter
 
Join Date: Feb 2010
Location: Leeds, England
Bikes: Meercat
Posts: 138
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
pedal/crank

Hi

My pedal has just come off my Izip electric cycle, and the thread on the crank looks to be very much stripped. I do have a couple of old bikes around. Are most cranks the same if I can salvage one from an old bike? Or might some form of putty/glue /filler secure my pedal to the crank.

Many thanks .. S
sevenhills is offline   Reply With Quote
Old 02-16-10, 03:51 AM   #2
dabac
Senior Member
 
Join Date: Mar 2008
Bikes:
Posts: 5,420
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 21 Post(s)
Forget about putty/glue/filler, they aren't strong enough. Cranks come in enough variations to make any prediction on the possibility of using parts from your old bikes very uncertain. A decent lbs will have tools and parts to put a thread insert into your damaged crank, but if it's a low-end model a straight off replacement might be cheaper.
If you insist on the budget approach you might get a better answer if you include pics of your possible donor bikes and your current bike.
dabac is offline   Reply With Quote
Old 02-16-10, 04:13 AM   #3
kmcrawford111
50/50 Road/eBike Commuter
 
kmcrawford111's Avatar
 
Join Date: May 2007
Location: Valparaiso, IN
Bikes: Specialized Roubaix, Specialized Sirrus, Brompton
Posts: 764
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Read up on this:

http://sheldonbrown.com/gloss_p.html#pedal

Determine your pedal axle diameter first.

Most pedals are 9/16". The threads can be "chased" with a pedal tap. I have these: http://parktool.com/products/detail....=27&item=TAP-6

But if the threads are as trashed as you say using a tap is probably a lost cause. Someone makes an insert that you can install in the crank to "replace" the damaged female threads, but I've never used one:

http://www.ride-this.com/index.php/e...ource=googleps

I reckon you'd need a drill and a different tap to cut the larger threads for an insert like this.

Make certain you check the threads on your pedal too. Those can also be refinished, with a die. I bought a left-hand die (and the aforementioned tap set) specifically for this purpose (pedal came out on my niece's bike, and the threads on both parts were both slightly damaged but repairable). These cutting tools are expensive so I would check to see if a local shop has them first. That's what I should have done, in retrospect. It's not like they're commonly-used tools for the home mechanic.

Remember that each side of the bike has a different thread direction and so needs a different cutting tool.

Might be a good idea to take the other pedal out and check the threads on that side as well?

Does anyone know how these threads get damaged like this? I'm curious.

Last edited by kmcrawford111; 02-16-10 at 04:23 AM.
kmcrawford111 is offline   Reply With Quote
Old 02-16-10, 06:39 AM   #4
Kimmo
bike whisperer
 
Kimmo's Avatar
 
Join Date: Dec 2009
Location: Melbourne, Oz
Bikes: copy/paste links: http://velospace.org/node/36949 http://velospace.org/node/47746 http://velospace.org/node/47747
Posts: 7,099
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by sevenhills View Post
Are most cranks the same if I can salvage one from an old bike?
Kinda... but not really, depends. +1 we need pics (or descriptions) to tell you.

Quote:
Or might some form of putty/glue /filler secure my pedal to the crank.
LOL. Epoxy might work for a toddler...
Kimmo is offline   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off



All times are GMT -6. The time now is 07:13 PM.