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One piece crank repair
#1
Good evening all.
I have a few sets of one piece cranks, all the same brand, that the sprocket tab (?) has broken off of. I do not have the tabs as they both are from 1985. Does anyone make replacement tabs that can be welded to the cranks so they can be used again? Other than the tabs missing they are in terrific shape and are the stock cranks for my bike.
Any help or info is appreciated.
Thanks
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#2
It should not be a challenge for a welder to provide a piece of rod of an appropriate size that can be welded to the arm. Just take the arm and chainwheel in so they know what size is needed. Of course one-piece crank arms are still available new as well.
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#3
Thanks for the reply and info.
I would like to keep my bike as stock as possible.
I have seen other cranks of the same brand and make for sale but this seems to be a common problem with them.
I guess the cost of repair will be the biggest factor.
I will search around today for a welder.
  Reply
#4
Good luck with the welding option, as I know that is what you prefer. I can understand the desire to keep your bike stock, but yours was not an unusual problem (indicated by the fact that you have 2 bikes in that condition) and many bikes therefore do not have the original crank arms. That was especially true for non-Schwinn bikes, as their crank arms were often cheaply made copies of the ones made by Ashtabula Bow Socket for Schwinn. Unless the bikes are highly desirable collectibles in excellent shape replacement does no actual harm, as the part is rather generic.

Here's an interesting thread about the Ashtabula crank and the company that made them: http://www.bikeforums.net/archive/index.php/t-760251.html
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#5
The cranks are SR Cosmo-lite. My original set is from my 85 GT Mach One bmx bike. The other set are from an 85 GT Pro bmx bike. Highly desirable? To me at least. Not quite sure why i like my bikes to be as stock as possible nstead of building them up with upgraded parts.
Cool thread on Ashtabula.
  Reply
#6
'85 was during the long fall of SR (Sun Tour) that started in the mid-late '70's. Sun Tour never understood the importance of charging enough to recover their R&D costs, and did not fund R&D adequately. When the slant-parallelogram patent for rear derailleurs expired, Shimano and others immediately copied it. Sun Tour never recovered. By the mid '80's much of their line was crap, with very few exceptions.

Sean; if you want to ride them, replace the cranks with something better, and get one good set to put on the bike when you decide to retire the bike and hang it on your wall.

I would get these:
http://www.amazon.com/Dimension-170mm-Cruiser-1-Piece-CrMo/dp/B001CJXBRM/
because they are forged chrome-moly alloy steel.
Nigel
  Reply
#7
The cranks are SR Cosmo-lite. My original set is from my 85 GT Mach One bmx bike. The other set are from an 85 GT Pro bmx bike. Highly desirable? To me at least. Not quite sure why i like my bikes to be as stock as possible nstead of building them up with upgraded parts.
Cool thread on Ashtabula.
  Reply


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