Bent Crank arm?

[zacapp]

Hey guys,

Had a crash only about a week ago and pretty majorly bent my pedal. At first I only thought it was my pedal that was bent but after putting on another pedal found that where the pedal actually attaches/ screws in is actually slightly bent too due to the impact. The actual crank arm is fine its just where the pedal screws in that is the problem. Is there any way I can bent this back or has anyone done it before? It might sound like a stupid question but, if worst comes to worst ill just buy a new crankset but these are only probably a month old and really don't have the money to buy another set.

Thanks,

Zac.

 

[wilddemon]

Can you post a pic? Are you saying the thread is damaged and the pedal is loose in that thread?

 

[zacapp]

You couldn't tell much from a picture. The actual part of the pedal that screws into the crank arm bent in the crash and as a result the part of the crank where the pedal screws in has bent along with it.

 

[wilddemon]

There's a few turner burners on here that might have a better idea but let's throw some around and figure out some viable ones and try to save them.

There was a turner that brought up heli coils in a recent thread and that is a possibility. You really want it to be solid. I think you will have to drill it out first. The other options are to add metal and tap it. I'm guessing the cranks are ally? Do you know anyone good at welding ally? Option 2 drill it out and put in an insert. You would need an accomplished turner to do this. Being a gong man there must be someone around who can do it. My neighbour prob could. Then you drill in sides and use a grub screw or two to pin it in place. Option 3 forget the insert and grub straight into the pedal. I don't think this would be very solid. If the thread is bent then the pedal could still flop about. Option 4 is tap the hole to next size up and use heli coil. These are supposed to be pretty reliable.

I'm pretty sure that other people will have other / better suggestions or variants of mine. You don't really want to weaken it with grubs maybe so maybe an insert with lead in chamfer and interference fit, and heat the ally, and chill the insert and press it might be better. I'm out but if other peeps have more suggestions I'm sure we could bounce off each other. Hope that is a reasonable start

 

[Clyde Dave]

There's a few turner burners on here that might have a better idea but let's throw some around and figure out some viable ones and try to save them.

There was a turner that brought up heli coils in a recent thread and that is a possibility. You really want it to be solid. I think you will have to drill it out first. The other options are to add metal and tap it. I'm guessing the cranks are ally? Do you know anyone good at welding ally? Option 2 drill it out and put in an insert. You would need an accomplished turner to do this. Being a gong man there must be someone around who can do it. My neighbour prob could. Then you drill in sides and use a grub screw or two to pin it in place. Option 3 forget the insert and grub straight into the pedal. I don't think this would be very solid. If the thread is bent then the pedal could still flop about. Option 4 is tap the hole to next size up and use heli coil. These are supposed to be pretty reliable.

I'm pretty sure that other people will have other / better suggestions or variants of mine. You don't really want to weaken it with grubs maybe so maybe an insert with lead in chamfer and interference fit, and heat the ally, and chill the insert and press it might be better. I'm out but if other peeps have more suggestions I'm sure we could bounce off each other. Hope that is a reasonable start

Option 5, buy new cranks!!!!!

 

[skwiz05]

Once bent, theyre munted. Get new ones.

 

[wilddemon]

Once bent, theyre munted. Get new ones.

Experience counts, and a fair bit of work in attempting a repair... Can ya borrow yer little sister's bike for a while?

 

[Wollongongrider1234]

my brother did that to his bike and i thought the same thing (just swap the pedals) but is didn't fix it. Now he just ides with a bent crank, it feels weird at first but you get used to it after a while.

 

[Toxicity]

Sounds like youve rooted your thread.. Yes you can re tap it.. But don't, it will never be as strong as it was orignally so I'm not even telling you how.. Buy new cranks..... My 2c as a metal worker....