Slipped crank arm

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Greeny76

New Member
Location
Kent
Hi all, New to the forum and looking for some advice please. Out on a ride the other day the left crank arm slipped when pushing off and is now at 90 degrees to the drive side crank arm, tried undoing the bolts and remove the cap on the crank and it wont budge, any thoughts on how to get the crank arm back to its correct position? Any advise would be greatly appreciated! (please see attached pic).
 

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Milkfloat

An Peanut
Location
Midlands
Happened to a friend on a ride, make sure you are releasing the retaining pin as circled below.

shimano-fc-5600-plate.jpg


You may need to get agricultural to get off the cranks. We had to use a rubber mallet and a lot of swinging to get the arm off. The splines were ruined so a new crank was fitted.
 

Threevok

Growing old disgracefully
Location
South Wales
The bolts The non drive side (left crank arm) may have come loose, causing the slip

Slacken the two bolts (without totally removing them) and place a flat head screwdriver in the gap to increase it, while wiggling the crank arm off

Providing you have not stripped the groves on the crank arm, you should be able to reinstall the arm at the correct angle, tighten (by hand) the middle bolt until there no play in the crank assembly then tighten the two bolts back up correctly

If you have stripped the groves off the crank arm, you will need a new one - or new crankset completely - depending on which is more economical
 
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Greeny76

Greeny76

New Member
Location
Kent
Thanks for the advise guys, but it is not moving! I think you might be right Skol new crank arm needed. I've found a new left crank arm for £34 online which seems pretty reasonable.

Spoke to the LBS and they've never come across one slipping like that, falling off because it's loose, yes... but not this! :ohmy:
 
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Greeny76

Greeny76

New Member
Location
Kent
@darrensmith0410 yes all the fruit and veg seems to end up in the same dish onto of the cooker (don't ask me!)
 

Levo-Lon

Guru
Incorrect tightening Willbe the reason it's slipped.
When you fit the new set ,tighten evenly to the required torque or hand pressure.
There not very tight but it's the even pressure that makes the crank stay put.

Either that or your a very strong goat on the hills :okay:
 

Milkfloat

An Peanut
Location
Midlands
I've never really figured out what that's supposed to do - what's it there for?

It is supposed to stop exactly this happening if the clamping bolts should come loose. If you have installed the crank correctly and you loosen up the bolts and try to pull off the crank arm and you'll see that it won't come off with the plate in place. I think it also forces you to put the cranks in the right pace when you install. If the cranks are not in the right place the pin won't go in the little hole and you won't be able to get the bolt through.
 
HTII Crank slippage is very common. Undo the little bolts that hold the arm on the spindle, then gently tap the arm off, with a mallet. Put it back on the right way ( 180 degree opposed to the other crank) then use the plastic centre bolt to tension the crank set up, with the plastic tightner you get with a HTII tool. Then retighten the spindle bolts to 12-14 Nm starting with the bolt closest to the frame.
 
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Greeny76

Greeny76

New Member
Location
Kent
Racing roadkill, thanks! so i managed to get the crank off. The grooves on crank arm and the shaft look all good, which is great, but the retaining pin broke, annoyingly. The top half snapped off leaving the rest inside the crank (including the pin). So will need to source on of those! Not sure how to get out the remainder of the broken one out though...
 
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