Crank arm coming loose
Discussion
I replaced the chainset on my Single speed (Genesis Flyer) a few months ago (I'm now running a Miche Primato Advanced chainset).
Twice now the non-drive crank arm has come loose mid ride. Is there solution to this other than doing the bolt up RFT? The crank arm states to torque the bolt to 35nm, I'm dubious about going RFT as the old crank-arm was well and truly stuck (My crank arm extractor broke removing it).
Has my new crank arm killed itself when it first came loose, deforming the ally and now it'll never fit?
Twice now the non-drive crank arm has come loose mid ride. Is there solution to this other than doing the bolt up RFT? The crank arm states to torque the bolt to 35nm, I'm dubious about going RFT as the old crank-arm was well and truly stuck (My crank arm extractor broke removing it).
Has my new crank arm killed itself when it first came loose, deforming the ally and now it'll never fit?
Fluffsri said:
Is this on a square taper? I had the same problem on my SS. In the end i ignored the torque value, applied lots of thread lock and grollied it in. Probably ridden a couple of hundred miles now and still tight, it was coming loose around 6/7 miles of riding.
Yep its a square taper. My SS only sees short journeys (my commute at ~5 mi/day), I reckon its come loose within 30 mi of last torquing it.Its reassuring to know you've had the same issue and sorted it! I'll get some thread lock and swing on the wrench tonight
Barchettaman said:
Clean the inside thread of the BB with acetone on a Q-tip, the crank arm bolt with acetone on a bit of rag, to remove any old threadlock. Allow to dry.
Apply threadlock (Loctite Blue should be fine) to the crank arm bolt.
Go gorilla on the bolt, should be fine.
This. I've had the same issues with my singlespeed numerous times and locktite blue usually makes sure it doesn't come undone!Apply threadlock (Loctite Blue should be fine) to the crank arm bolt.
Go gorilla on the bolt, should be fine.
walm said:
ecsrobin said:
I thought square taper was long since dead?? If it's coming off after that short a distance I would say the crank arm is deformed.
For some reason they are all the rage on fixies/SS - I have had three of them. [/hipster]Edited by Fluffsri on Friday 2nd October 12:36
It's completely binary. Either your crank arm is bent and it will work itself off threadlock or not - or your crank arm is fine and threadlock+torque will solve the whole thing.
My f@cked crank arm was very obviously f@cked. You could see the deformation in the corner of the square bit.
My f@cked crank arm was very obviously f@cked. You could see the deformation in the corner of the square bit.
walm said:
ecsrobin said:
I thought square taper was long since dead?? If it's coming off after that short a distance I would say the crank arm is deformed.
For some reason they are all the rage on fixies/SS - I have had three of them. [/hipster]ecsrobin said:
walm said:
ecsrobin said:
I thought square taper was long since dead?? If it's coming off after that short a distance I would say the crank arm is deformed.
For some reason they are all the rage on fixies/SS - I have had three of them. [/hipster]Not sure there's a huge price difference.
Campag square taper is £50!
You've got nothing to lose by over-torquing it, the head of the bolt might shear off I guess but it sounds very much like the crankset is dead anyway so you may as well go for it.
When you decide you've had enough get an old 165mm Shimano crank and the USE converter ring:
And rock out with your cock out.
When you decide you've had enough get an old 165mm Shimano crank and the USE converter ring:
And rock out with your cock out.
AyBee said:
Barchettaman said:
Clean the inside thread of the BB with acetone on a Q-tip, the crank arm bolt with acetone on a bit of rag, to remove any old threadlock. Allow to dry.
Apply threadlock (Loctite Blue should be fine) to the crank arm bolt.
Go gorilla on the bolt, should be fine.
This. I've had the same issues with my singlespeed numerous times and locktite blue usually makes sure it doesn't come undone!Apply threadlock (Loctite Blue should be fine) to the crank arm bolt.
Go gorilla on the bolt, should be fine.
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