Mutinying chainring bolts

Thread started by
HappyLand at 06.26.09 - 12:35 pm
My ex called me yesterday to tell me that while riding his bike up a hill, three of his chainring bolts popped out and the remaining two were loose. He went to a bike shop to fix it and discovered that the chainring was squished into a more oval shape somehow and would not align correctly with the holes on the crank arm. Mysterious.
The bicycle in question is a retro Schwinn Centurion and about three months ago, he removed the inner chainring to convert it from a 12 speed to a 6 speed using new wider chainring bolts to attach the ring to the crank. My theory is that since he did not use grease to install the bolts, he might have stripped the threads on one of the bolts, and once loosened, the force of pedaling up the hill knocked all the other ones out and compressed the chainring? Somehow?
Either that or SABOTAGE!!!
My bike mechanic knowledge is fairly limited, but I'd like to know more, that's why I'm asking what you guys think.
My ex lives in SF and commutes 2 miles each way to work, and occasionally takes a longer hillier route for exercise. He does only errand riding really, so he's not on his bike that much.
DISCUSS:
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3/32 bcd chainrings are sort of oval to begin with. when i say oval i mean not 100% circular. its just the way they are made, stamped out of a piece of sheet metal vs being cnc machined like track rings or whatever.
if he put a lot of torque on the chainring with loose cr bolts, then he would bend it even more than it already is.
ruinedbyidiots06.26.09 - 12:40 pm
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Cool thanks, I'm glad I wasn't that far off then.
It's an easy repair, but we're just puzzled over how the chainrings got out in the first place...and how to prevent this situation in the future.
HappyLand responding to a
comment by ruinedbyidiots
06.26.09 - 12:49 pm
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While I truly appreciate your suave advances (Truly, I do), I gotta admit I got a bad case of the sads lately and my no-no has lost interest in playing with others...or even just with me.... : {
HappyLand responding to a
comment by coldcut
06.26.09 - 1:15 pm
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