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Old 02-10-08, 10:28 PM   #1
ecp8
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New life for stripped crankset

I'm building a fixed gear polo bike on the cheap and have been pulling parts from my parts box to put on a sturdy lugged omega frame I found. I have a truvativ fixed gear crankset with one stripped pedal thread, Is there hope for salvaging this crankset? Does locktight work? Or is there a liner that can be used? This is not going to be a commuter or real road bike - just a knock about polo bike.
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Old 02-10-08, 11:23 PM   #2
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In theory inserts could be placed to repair the thread. Locktite, short
of the industrial strength stuff needing an oxy torch to remove is unlikely to work.
JB Weld is similar and worth a try but really, surplus old cranks are a 'dime a dozen'
if you check LBS where cast offs stack up and should be available cheaper than
a 1/2 donkey solution, especially if the L crank is involved. If you gamble on JB
or heavy duty locktite, adding a couple of allen set screws on either side by
drilling and tapping the 9:00 and 3:00 positions or at least the 6:00 position to
help lock the shaft in place. I doubt any of the epoxy variants are strong enough
for this duty though.
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Old 02-11-08, 07:29 AM   #3
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Quote:
Originally Posted by sch View Post
If you gamble on JB
or heavy duty locktite, adding a couple of allen set screws on either side by
drilling and tapping the 9:00 and 3:00 positions or at least the 6:00 position to
help lock the shaft in place. I doubt any of the epoxy variants are strong enough
for this duty though.
If you're just cruising - no standing climbs - this has been proven effective if done right. I just did the 6:00, but maybe 9, 6, and 3 would be good to add some stability in all directions.
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Old 02-11-08, 07:30 AM   #4
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left or right crank?

left cranks are a dime a dozen, just replace with another left crank of the same length. cheap.
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Old 02-11-08, 09:14 AM   #5
sch
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My set screw/JB weld offering was tongue in cheek, I don't really advise
doing this. Surplus cranks are not hard to find and there is no great virtue in
fixie cranks unless you are a clyde or 400watt type. It was offered in a
spirit of Make magazine.
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Old 02-11-08, 11:06 AM   #6
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Your LBS can repair the stripped crank at small cost ($10?).
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Old 02-11-08, 12:18 PM   #7
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Not even the strongest locktight will hold in this application for long. I would doubt that JBWeld would either, since it is just epoxy which has low shear strength.

LBS can put a heliocoil in for not much money. Or find another random arm and put it on there.
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Old 02-11-08, 02:56 PM   #8
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retap it to the BMX standard.
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Old 02-11-08, 07:14 PM   #9
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Thanks for the advice. I'll check the LBS for retapping. It looks like there's a market for orphan crank arms out there.
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