Pedal related technical question

[Speed2XS]

Alrighty,

So help me out here people. I recently sold a bicycle to a nice young man and his girlfriend. They paid cash, and they got a very well tuned used bicycle in return. A couple days later the gentleman calls back and says that he had a problem with a pedal comming off while his girlfriend was riding it. I told him to call if there were any immediate mechanical problems, so this was no problem. I have no intention of selling someone something that is broken. So I ask him to bring it over so i can see what happened. He brings me the bike, looking like it has gone down on the right side (same side as the pedal off), and says that she fell when the pedal came off. I take the bike in for repair and view the damage.

This is where I need help/opinions. I think I know what I see, but dont know for sure, but who can really except for them, right? Anyway, I didnt take pics of the crankthreads, but the first 3-4 rows of threads were trashed/friction welded. I chased them them and have been able to save the crank for further use on the bike. Here are pics of the pedal, I have not changed a thing about it, it's just as i recieved it:

My question is, could this damage be the result of a pedal not having been on securely? I feel very confident nothing left my house loose, and the pedal definately did not look like this when it left either.... . I'm gonna fix it for the guy, use loctite to secure the used replacement pedals I am providing, and a paint pen to mark all the bolt positions on this and future bikes.

Thanks in advance.

 

[Schwinnspastic]

looks like it loosened up till it could not hold the load on the last couple threads....xxit happens , good on ya fixing the problem for them.

 

[sensor]

looks like it loosened up till it could not hold the load on the last couple threads....xxit happens , good on ya fixing the problem for them.

thats exactly what i was seeing too

 

[Speed2XS]

Alrighty. I just wanted to make sure I wasnt being played for a fool. Thanks for the input.

 

[12bcruzin]

Alrighty. I just wanted to make sure I wasnt being played for a fool. Thanks for the input.

Curious, how are you being "played"? You are lucky nobody got hurt and this got turned into a big deal. That is the risk of buying and selling old bikes. Old loose threads, worn out or cracked used parts, seized bearings and tire blowouts can come back to haunt you. You might consider a little liability insurance policy to cover your .......
But to answer you question, often on old bikes, old rusty pedals start to seize up and can back themselves out of the crank. Then instead of getting replaced, owners will keep tightening the pedal-further straining the threads in the crank and pedal. Eventually, the threads will no longer hold the torque required to keep the pedal locked into position and will keep loosening until it finally strips out. Fortunately, the cranks are forged and of better material than the pedal shaft so most of the wear is to the pedal shaft (see your pic). But be warned, there is more than likely wear to the crank too, how much is debatable and how much of a risk...time will tell. Sometimes it is cheap insurance to use brand new cheap pedals due to the fresh thread diameter and better, tighter fit in old cranks.

 

[Speed2XS]

Alrighty. I just wanted to make sure I wasnt being played for a fool. Thanks for the input.

Curious, how are you being "played"? You are lucky nobody got hurt and this got turned into a big deal. That is the risk of buying and selling old bikes. Old loose threads, worn out or cracked used parts, seized bearings and tire blowouts can come back to haunt you. You might consider a little liability insurance policy to cover your beep...

I am unfortunately very aware of liability issues in business having come from a very litigious industry myself.

But to answer you question, often on old bikes, old rusty pedals start to seize up and can back themselves out of the crank. Then instead of getting replaced, owners will keep tightening the pedal-further straining the threads in the crank and pedal. Eventually, the threads will no longer hold the torque required to keep the pedal locked into position and will keep loosening until it finally strips out. Fortunately, the cranks are forged and of better material than the pedal shaft so most of the wear is to the pedal shaft (see your pic). But be warned, there is more than likely wear to the crank too, how much is debatable and how much of a risk...time will tell. Sometimes it is cheap insurance to use brand new cheap pedals due to the fresh thread diameter and better, tighter fit in old cranks.

My concern was whether or not the part had been taken off after purchase and cross threaded during reinstallation. This buyer is a young person, putting together bicycles themselves as well and it was evident that the bicycle had been treated harshly since purchase. In retrospect I intend to mark every bolt and nut I take off and reinstall to verify if tampering is suspected in the future. It's unfortunate that honest people have to be so aware of their "beep" these days. Makes one tempted to just live off the government and never do anything contributory or productive again. :roll:

 

[12bcruzin]

I guess then in my opinion, there is no way of knowing or proving one way or the other. Logic says that they would not have a reason to take the bike apart unless there was a problem and even then they would more than likely have brought it to you as the seller. The threads look as though they were ridden on half out of the crank but they also look cross threaded. Was that because the pedal loosened and they screwed it up putting it back in? Did they ride on it loose? Did you leave it loose?
There is no good answer to this as all are possible. If I was the customer, I understand that it was a used bike, used parts and would be willing to pay some of the cost to fix it if I was not capable of fixing it myself. But that is just me. Other people may have the Walmart mentality of customer always right and you are always going to be at fault..In the future, you may want to go over such possibilities with customers and make sure that they understand. Maybe even check the tightness of the seat, bars, wheels and pedals right in front of them to help remove doubt but in the end, there will always be people that put a stick in your spokes...

 

[Speed2XS]

In the future, you may want to go over such possibilities with customers and make sure that they understand. Maybe even check the tightness of the seat, bars, wheels and pedals right in front of them to help remove doubt but in the end, there will always be people that put a stick in your spokes...

For sure, very good suggestions. All is good now as I delivered the bike to him in better condition than I received it back in, he was happy (even asked if he owed me anything), and it was a learning experience for me as well.