Self Loosening Cranks?
04-29-05, 06:00 AM
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Self Loosening Cranks?
I got some help here a while back with a clicking from my cranks. It turned out they were a bit loose. Sure enough, when I tightened everything (with a torque wrench) the noise went away.
Here's the new problem: They won't stay tight. I have removed the bolts, cleaned all threads, regreased and reinstalled. Now every time I ride to work and back (14 mile round trip) I get the clicking sounds again. Sure enough, the bolts are loose when I check them. I would guess they are down to around 15 ft lb.
I'm hoping some of you experienced shop guys can catch something I'm missing.
Here's the new problem: They won't stay tight. I have removed the bolts, cleaned all threads, regreased and reinstalled. Now every time I ride to work and back (14 mile round trip) I get the clicking sounds again. Sure enough, the bolts are loose when I check them. I would guess they are down to around 15 ft lb.
I'm hoping some of you experienced shop guys can catch something I'm missing.
04-29-05, 06:20 AM
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You can try Loctite but if that does not work read below.
Here's how I remedied the same situation:
When the cranks were loose the metal inside the square taper of the crank arm was damaged.
The cranks were now sliding so far onto the tapered spindle that they were hitting the end of the taper (where the spindle goes from square to round).
To fix remove the offending crank(s), using a flat file or dremel, file/grind a chamfer on the inside edges of the square taper at about a 45 deg angle (with respect to the flat face of the crank arm).
Take care to not damage the inside surface of the square taper.
When you have removed about 0.060" of material from all four edges of the square taper hole re-install the crank arm and torque to spec. (you may have to remove more material if your damage is severe).
My cranks have not come loose in four months of hard FG riding after the above procedure. Prior to the fix I had to tighten them twice a week
Enjoy
Here's how I remedied the same situation:
When the cranks were loose the metal inside the square taper of the crank arm was damaged.
The cranks were now sliding so far onto the tapered spindle that they were hitting the end of the taper (where the spindle goes from square to round).
To fix remove the offending crank(s), using a flat file or dremel, file/grind a chamfer on the inside edges of the square taper at about a 45 deg angle (with respect to the flat face of the crank arm).
Take care to not damage the inside surface of the square taper.
When you have removed about 0.060" of material from all four edges of the square taper hole re-install the crank arm and torque to spec. (you may have to remove more material if your damage is severe).
My cranks have not come loose in four months of hard FG riding after the above procedure. Prior to the fix I had to tighten them twice a week
Enjoy
