sisdavid

My crank arm on my left is clicking when I press down. I took the pedals apart and re greesed and it did nothing. same click I tightened up the bolt on the crank and it still does it. It is a Shimano cassete type bottom bracket. does not seem to be any excessive play. Could have sworn when I tightened the bolt that holds the crank on that it stripped, but I looked at the threads and it seemed okay, so I put the bolt back in and tightened it just before it does the stripping slip thing about 15 lbs. This clicking really is getting on my nerves what is wrong?

sooprvylyn

Square taper spindle?

sooprvylyn

If it is a square taper it is quite possible that your left side crank arm is trashed. This is a common problem with left side crank arms on square taper spindles. You wont notice the play just from hand wiggle as it can take 50+ lbs of force to actually show the play. Usually it feels like a slight unevenness in the pedal stroke, almost like a clicking, but not usually too audible. My bet is that at some point the spindle bolt was not tight enough allowing the crank arm to loosen, and then round out slightly as you rode it.

This is easily detected when riding. Stand on the pedals so the crank arms are parallel to the ground left side forward. Then sit down and pedal 1/2 revolution lightly so the pedals are again parallel right side forward. Stand up, do you feel the pedal give a little? If so then you have a trashed crank arm.

sisdavid

It is a square style. Yes I think this is the problem. How tight should the bolt holding it on be?

sisdavid

The bolt that holds it on looks kind of small does not look like it could take much torque.

gerald_g 

If the crank arm square gets enlarged, then no amount of tightening on the retaining nut, will fix the problem.
You'll need to replace the arm.

(please someone correct me if I am wrong.)

sooprvylyn

Yeah if the arm is enlarged then it is trashed, period. This is a VERY common problem with square taper spindles, left side arms go fast if they are not torqued very tight.

Both the Bolt AND the Spindle are made of hardened steel and they are both VERY strong. I find that the regular black steel bolts with the hexbolt head(not allen type) hold the best. I torque mine till they dont turn any more with about probably 50-60 lbs of force.

I only had this problem once, then i learned to make sure those bolts are really f'ing tight. After install check em after every ride for the first 100 miles or so to make sure they dont get loose. You can use some lite locktite on the threads to help keep em tight.

If you switch to one of the newer splined spindle/crank systems this is no longer a problem.

kmcrawford111

Why is this problem particular with the left side? Is it because there are no chainrings there = less material = weaker overall?

sisdavid

Does anyone have a spare crank arm? Ya, the bolt when I started torquing on it was way loose, no where near 50 or 60lbs. Has to be it. Do I have to have a crank arm off the same brand?

sisdavid

also what is the diff between 170mm and 175mm?

kmcrawford111

^ A 5mm longer crank arm.

DannoXYZ 

Left side because it transmits torque through the spindle. This causes some wiggling between the crankarm and spindle which eventually loosens the bolt. Right side crankarm doesn't apply torque to the spindle. Most of the force on the right side goes from the crank-spider to the chainrings.

Here's a link to the Park Tool - Torque Specifications. If the OP has a square-taper crank, it'll need somewhere between 27-33 lb*ft torque. Simply no way to generate that kind of torque with itty-bitty L-shaped allen-keys. You need at least a 12" automotive-style ratchet-wrench with allen-bit. Whenever I ask people with squeaking or loosening crankarms how much torque they used on the crankarm, they have no idea because they didn't measure it. About 99.9% of the time, it's been too low, and seriously too low, like only 50% of the required torque. If his bolt is slipping at 15-lb*ft, then either the bolt or spindle is stripped, or both.

sisdavid

Good news I tightened the bolts with a 3/8 drive and a allen wrench that fits in socket set. The handle on the wrench is maybe. 8" I tightened it up as tight as I could, and I am a strong guy. I think maybe I heared it click once then when I got home I gave it another 2 thenths of a turn. No more clicking or squeaking. Hopefully it stays that way. But thanks to you guys I got it narrowed down. Thanks to Soop and others for putting me on the right track. Atleast I know what it is

DannoXYZ 

So ahh... how much torque did you use on that bolt???

Jeff Wills

Seriously... I don't care how strong you are, an 8mm in a normal socket wrench isn't going to cut it. Take that Allen socket, put it on a torque wrench, and find out!