Ultegra crank nut/bolt sheared off in my hand

cojones

...and it's made of plastic. My understanding is that it is used simply to draw/hold the crank in the correct place while the two crank bolts are tightened to secure the crank (a bit like the stem bolt), so I wasn't putting excessive force through it so why did it shear off? Is my understanding wrong?

markos1963

cojones wrote:

...and it's made of plastic. My understanding is that it is used simply to draw/hold the crank in the correct place while the two crank bolts are tightened to secure the crank (a bit like the stem bolt), so I wasn't putting excessive force through it so why did it shear off? Is my understanding wrong?

Sheared or cross threaded? Did you use the right tool to tighten it up? The tool is design to stop you from over tightening.

cojones

markos1963 wrote:

cojones wrote:

Sheared or cross threaded? Did you use the right tool to tighten it up? The tool is design to stop you from over tightening.

Sheared. The thread part of it is still in the crank (I'll worry about getting it out when the replacement nut arrives). I have got the right tool but should it be tightened by hand only or by a spanner/lever (I used the latter when it sheared off).

markos1963

cojones wrote:

markos1963 wrote:

cojones wrote:

Sheared or cross threaded? Did you use the right tool to tighten it up? The tool is design to stop you from over tightening.

Sheared. The thread part of it is still in the crank (I'll worry about getting it out when the replacement nut arrives). I have got the right tool but should it be tightened by hand only or by a spanner/lever (I used the latter when it sheared off).

Only by hand, the tool I have doesn't have anything other than a thumb wheel for purchase.

cojones

Thanks markos...there's my answer right there then!! :?

TheRealGuybrush

Some of those end cap tools have spanner flats or an allen key socket so you can put more force through them.

It's only for loosening them however if they become seized and you don't have thumbs of steel. Bad luck sir!

keef66

Stick a chisel or big screwdriver through the remains if you want to remove it from the crank. Replacements are pretty cheap.

As above, the tool I have is clearly designed to ensure it's used by hand, and only finger tight. You'll accelerate BB bearing wear if you've over tightened it.

crankycrank

Seems to me that when the clamping bolts are loose (take them completely out of the arm) the broken piece should come out fairly easy. Use a sharp pick of some sort to turn from either side and you could also use a plastic wedge to spread the clamp opening just slightly if it refuses to budge.