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

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.

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.

Kinda... but not really, depends. +1 we need pics (or descriptions) to tell you.

LOL. Epoxy might work for a toddler...