re-threading cranks

[cyclenut]

So I lent two road bikes to a colleague for him and his fiance to make a decision about getting into road riding.  They had the bikes for 6 weeks (as agreed).

 

I got them back last week and went to put the original pedals back on (he used their MTB pedals) only to find that in putting on his pedals he delicately managed to cross-thread all four cranks .... yes, all four  

 

Is this a quick fix from the LHS (local hardware store) or do I need to run the bikes to the LBS 

What's the probability of changing the diameter (post re-threading) - will it dramatically affect the fit of new pedals

 

(it's my fault for assuming that because he had a pedal spanner at home he had sufficient knowledge to complete the job.)

[Weekend_Warrior]

new cranks are the answer to that. 

Then send him the invoice

[dirtrider]

This is a job for engineering shop . Going slightly oversize will really mess it up further .

[Weekend_Warrior]

i have 1 sora crank that is cross threaded the otherside is ok, what make of cranks are they maybe some hubbers have some odd sides laying around

[Racer X]

Make sure that dodgy mate of yours pays for the re-threading.

[cyclenut]

new cranks are the answer to that. 

Then send him the invoice

 

I just bought the cranks (105) off the hub to finish the bike build (specialised).  I'd never even ridden the bike

 

Won't be sending him the invoice.  It's my choice, therefore my risk.

[cyclenut]

Make sure that dodgy mate of yours pays for the re-threading.

 

At the moment he's still a colleague .... not sure how much time needs to pass until the friendship/mate thing materialises

[Jules]

Ouch. Hope it comes right for you. Is your colleague aware of the damage he's done?

[TNT1]

 

 

 

TNT12008-09-29 02:59:48

[Weekend_Warrior]

... not sure how much time needs to pass until the friendship/mate thing materialises

 

I dont know if it ever will maybe u should pay half and half if you feel partly responsible.  If i damaged another guys stuff i would offer to pay for it.

 

 

[Johan Bornman]

This is not a machine shop job as the right-hand cranks are Left Hand threaded. I doubt they'll have such a tap for the job. I suggest you first try and screw the pedals in from the inside of the crank, therefore hopefully starting off with what is still the remaining bit of of good thread. This might fix the thread enough so that you can then screw the pedals in from the other side.

 

I've used this twice and it worked each time.

 

Failing that, you'll have to find a shop with a set of crank taps. Given today's throw-away culture, I think you'll have to try all the shops you know.

 

In the US bike catalogues crank rethreading inserts and tools are standard items but I've not seen them here in anyone's tool catalogue.

 

 

[cyclenut]

Make sure that dodgy mate of yours pays for the re-threading.

 

At the moment he's still a colleague .... not sure how much time needs to pass until the friendship/mate thing materialises

Dude' date=' you lent him your bike, we just assumed then... I mean would you lend out your wife to just anyone?
[/quote']

 

 TNT1 - Go Away .... this is not a thread for you to hi-jack. 

 

If you read the thread probably, you would notice I said it was my choice and therefore my risk.  Ask those who know me - I do this because I'm passionate about the sport and growing it.  I will continue to do so.

 

Unrelated comments, no matter how witty they might be to you (particularly if you mention my wife) are not welcomed.

 

cyclenut2008-09-29 02:58:35

[dirtrider]

Please find a new engineering shop !! My goodness a place where they can not do left or right handed threads is not an engineering shop , it is called a hardware store ! You can do what Johann suggested but go and find a decent pedal (from a makro bike ) as they cut threads easier .

[cyclenut]

This is not a machine shop job as the right-hand cranks are Left Hand threaded. I doubt they'll have such a tap for the job. I suggest you first try and screw the pedals in from the inside of the crank' date=' therefore hopefully starting off with what is still the remaining bit of of good thread. This might fix the thread enough so that you can then screw the pedals in from the other side.

 

I've used this twice and it worked each time.

 

Failing that, you'll have to find a shop with a set of crank taps. Given today's throw-away culture, I think you'll have to try all the shops you know.

 

In the US bike catalogues crank rethreading inserts and tools are standard items but I've not seen them here in anyone's tool catalogue.

 

 

[/quote']

 

Thanks JB - a handy Tip and one I had not thought of.

[Johan Bornman]

Please find a new engineering shop !! My goodness a place where they can not do left or right handed threads is not an engineering shop ' date=' it is called a hardware store ! You can do what Johann suggested but go and find a decent pedal (from a makro bike ) as they cut threads easier .[/quote']

 

The problem is that the thread is not a standard metric thread. Even if they did have a set of taps in left and right hand threads, you're limited to available thread pitch taps.

 

If the crank were something you could get into a lathe a skilled turner would cut the thread with a thread tool, but it is an awkward form that won't fit into any chuck.

 

I think most pedals have a thread that's shorter than the crank's thickness  and my guess is therefore there is some salvageable thread left on the crank's inner side.

 

 Makro bikes have pedals with a different thread - smaller diameter and different pitch.

 

I have no doubt those cranks can be saved. Patience and thought will do the trick.

 

 

 

 

 

[dirtrider]

Mmmm I think you right , I forgot we talking about road bikes here .