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left crank falling off

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left crank falling off

Old 06-15-19, 09:11 AM
  #1  
RubeRad
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left crank falling off

Tried to go for a mtb ride today, left crankarm (Surly Mr Whirly) came loose. With my multitool I was able to wrangle the two pinchbolts and get it back on, 5min later it was falling off again. So I put it back on a 2nd time and rolled downhill back home (without making it to the top )

Is the whole crankset toast, or could I get by with a replacement left arm? Where could I even find one? A little searching did not turn up any left arms (hardly any whole cranksets, and those were ungodly expensive! (for me)) Does Surly even sell cranksets anymore? Their redesigned website doesn't have pages for any cranksets, and only shows two chainrings, there used to be so much more

Are there cranksets from other brands that would mate with the mr whirly splines? I wouldn't mind a frankencrank.

Or can anybody point me to cheap 1x cranksets with 58bcd? My surly 28T narrow-wide chainring is nearly new, and I'd hate to have to ditch it.
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Old 06-15-19, 09:39 AM
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Multitools suck. Try torquing it correctly with a proper tool, or even better a torque wrench. I know, I know, real mechanics don't need them.....
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Old 06-15-19, 09:45 AM
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Originally Posted by RubeRad View Post
Tried to go for a mtb ride today, left crankarm (Surly Mr Whirly) came loose. With my multitool I was able to wrangle the two pinchbolts and get it back on, 5min later it was falling off again. So I put it back on a 2nd time and rolled downhill back home (without making it to the top )

Is the whole crankset toast, or could I get by with a replacement left arm? Where could I even find one? A little searching did not turn up any left arms (hardly any whole cranksets, and those were ungodly expensive! (for me)) Does Surly even sell cranksets anymore? Their redesigned website doesn't have pages for any cranksets, and only shows two chainrings, there used to be so much more

Are there cranksets from other brands that would mate with the mr whirly splines? I wouldn't mind a frankencrank.

Or can anybody point me to cheap 1x cranksets with 58bcd? My surly 28T narrow-wide chainring is nearly new, and I'd hate to have to ditch it.
One arm is certainly toast. Given that the spindle is cro-moly there's a chance it isn't too mangled and can still be used....but not seeing any photos who knows.

What is "cheap"? Cranksets usually aren't...and a 58mm BCD spider is the definition of bizzarro sizing....
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Old 06-15-19, 09:56 AM
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at least you can buy a new left without buying both..

talk to your LBS with a QBP account to order one..

Bene Sugg:
more pre ride bolt tightening checks on your schedule ...
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Old 06-15-19, 10:22 AM
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I will call LBS when they open, if it is possible to order a left arm I expect it would be the best solution. I guess the arms are alu, because it says the spindle is cromoly. I forgot to say, this is the 2nd incident with the left arm coming loose. The first time I cleaned all the mating splines as well as I could, added a little fresh grease, and put it back together.

Instructions say drive side crank-arm pinch bolt gets 37 lb-ft, and non-drive-side gets only 7 lb-ft (!!) That's not much at all, I'm sure I got more than that with the multitool, is my problem maybe from overtightening? (Not that at this point I could solve the issue by putting it back on looser)
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Old 06-15-19, 12:01 PM
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For reference, here's a 1x crankset that is affordable. It says it can do 68/73 (Krampus is 73). How crappy is it? I'm a little curious to try an oval chainring.
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Old 06-15-19, 12:07 PM
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My LBS says QBP says no. So I guess I'm shopping for a new crankset. Will probably buy that cheap chinese one off ebay for $50.

Meanwhile, if anybody has a line on somebody wanting to unload a used Mr Whirly (no chainrings needed), please send them this way.
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Old 06-15-19, 12:11 PM
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Here's one for $82. Looks like my fat-a$$ is going to be stuck with bumping up from 28T to 32T
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Old 06-15-19, 12:31 PM
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As the LBS has done Mid drive conversions , they have removed a few wide BB shell BB and cranks ,

but not selling the QBP bikes * much , mostly Framed minnesota .. lower cost ..


*unless special ordered .. reboxed and shipped a few for Coasties on Kodiak Isl Base.. AK.
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