Threads on crank shredded, is there a solution?? PLEASE HELP !!

[brunocar5]

I bought an old bike, basically for the frame (Reynolds 453). And after completing at least a months restoration, the bike was put back together, whilst riding the crank bracket came loose and I tried to put it back on without success. I took it to the local bike shop and was informed that the bolts were put on incorrectly, i.e left hand thread put on right hand so and vice-versa. He said that the threads might be knackered on the frame now, and if that is the case then the frame is scrap............

Now you can imagine after putting in all that effort, I'm not best pleased, more so, as the crank was put back together by someone else (trying to help).

My question is this : If the threads are done, is there a way of securing the crank, but NOT screwing into the frame ?

The frame was probably made in the 70's, and is on an old Falcon Team Equipe bike.

Your help would be appreciated.

Cheers

Steve

 

[DiabloScott]

I bought an old bike, basically for the frame (Reynolds 453). And after completing at least a months restoration, the bike was put back together, whilst riding the crank bracket came loose and I tried to put it back on without success. I took it to the local bike shop and was informed that the bolts were put on incorrectly, i.e left hand thread put on right hand so and vice-versa. He said that the threads might be knackered on the frame now, and if that is the case then the frame is scrap............

Now you can imagine after putting in all that effort, I'm not best pleased, more so, as the crank was put back together by someone else (trying to help).

My question is this : If the threads are done, is there a way of securing the crank, but NOT screwing into the frame ?

The frame was probably made in the 70's, and is on an old Falcon Team Equipe bike.

Your help would be appreciated.

Cheers

Steve

I think your LBS may be giving you BS. I don't think you could possibly have screwed your bottom bracket in backwards (I assume by "bolts" you mean the cups). You might very well have knackered your threads by cross threading but that would have been obvious from the start. You might also have damaged your crank by getting it on the spindle improperly.

There is a comonent called a helicoil that is used for stripped out threads that might work on your bike, but I think you really need a better diagnosis.

 

[rickt]

I have to go along with diabloscott on this one. I am a mechanical fitter and machinist by trade and a cyclist of 37 years experience and have seen many stripped bottom brackets and threads of all sorts. It is HIGHLY improbable that the cups were put on the wrong side. What diablo was suggesting about the cross threading is that whom ever was fitting the cups should have felt a lot of tension required to turn the spanner (wrench to the yanks). I have seen bottom brackets repaired by bronze welding the damaged thread and tapping new threads into the bronze, but I don't believe this is the ideal method. Surely a local frame builder could replace the bottom bracket for a reasonable fee without compromising the aesthetics of the frame.

 

[artmichalek]

I have to go along with diabloscott on this one. I am a mechanical fitter and machinist by trade and a cyclist of 37 years experience and have seen many stripped bottom brackets and threads of all sorts. It is HIGHLY improbable that the cups were put on the wrong side. What diablo was suggesting about the cross threading is that whom ever was fitting the cups should have felt a lot of tension required to turn the spanner (wrench to the yanks). I have seen bottom brackets repaired by bronze welding the damaged thread and tapping new threads into the bronze, but I don't believe this is the ideal method. Surely a local frame builder could replace the bottom bracket for a reasonable fee without compromising the aesthetics of the frame.

Agreed that you wouldn't be able to get the cups into the wrong sides unless you were really trying hard. Another possible fix is if the bb has an English thread there might be enough metal there to re-tap it for an Italian thread, which is 1mm larger in diameter.

 

[hd reynolds]

If all else fail as per the suggestions of the others here, a last resort is to have a new BB brazed. Its a cinch for any custom-builder.

 

[John M]

I bought an old bike, basically for the frame (Reynolds 453). And after completing at least a months restoration, the bike was put back together, whilst riding the crank bracket came loose and I tried to put it back on without success. I took it to the local bike shop and was informed that the bolts were put on incorrectly, i.e left hand thread put on right hand so and vice-versa. He said that the threads might be knackered on the frame now, and if that is the case then the frame is scrap............

Now you can imagine after putting in all that effort, I'm not best pleased, more so, as the crank was put back together by someone else (trying to help).

My question is this : If the threads are done, is there a way of securing the crank, but NOT screwing into the frame ?

The frame was probably made in the 70's, and is on an old Falcon Team Equipe bike.

Your help would be appreciated.

Cheers

Steve

If the BB threads on the frame are shot, you can replace the BB with a YST threadless BB made expressly for this problem. They are available in square-taper only (which would probably fit your crankset for that older bike).

In the UK from:

http://www.sjscycles.com/store/vIndex.htm?item4521.htm

and in the USA from:

http://www.biketoolsetc.com/