BB replacement, crank issue

Alanstrainor

Hey guys,

So I have a crank set similar to the following:

http://i.imgur.com/pkMPaYC.jpg

It's a single speed, so the crankset is pretty unique/unknown.

Anyway, I replaced my BB on the weekend, but the left (non drive) side was missing a part thanks to the last bike shop that replaced it. It is missing the screw cap/seal that goes on the crank. In the picture above this cap is missing, and you can see the cog/thread.

So, when I replaced the crank, and tightened it all up, after a short cycle, the non drive side crank came loose. How on earth will I fix this without the part? Is it even possible? Let me know if I'm not making any sense...

ford2600

Alanstrainor wrote: »

Hey guys,

So I have a crank set similar to the following:

http://i.imgur.com/pkMPaYC.jpg

It's a single speed, so the crankset is pretty unique/unknown.

Anyway, I replaced my BB on the weekend, but the left (non drive) side was missing a part thanks to the last bike shop that replaced it. It is missing the screw cap/seal that goes on the crank. In the picture above this cap is missing, and you can see the cog/thread.

So, when I replaced the crank, and tightened it all up, after a short cycle, the non drive side crank came loose. How on earth will I fix this without the part? Is it even possible? Let me know if I'm not making any sense...

The image you posted is a double/compact crank?

The two pinch bolts tighten the crank to spindle; you didn't tighten them properly.

The cap you are missing is to preload the external cup bearings.

GCN on YouTube or Park Tools is your friend

Alanstrainor

ford2600 wrote: »

The image you posted is a double/compact crank?

The two pinch bolts tighten the crank to spindle; you didn't tighten them properly.

The cap you are missing is to preload the external cup bearings.

GCN on YouTube or Park Tools is your friend

I feel I did tighten them, but I worry that without the preload cap that I was doomed to failure?

I don't have a torque wrench with low enough calibration to torque the bolts, but my process was to tighten one a half turn, then switch to the other, and switch back and fourth until it was as tight as I thought was reasonable.

Is that a reasonable process? I followed a few guides on youtube.

EDIT: That image was just to show the spindle, non drive crank. You can ignore all the rest.

ford2600

Alanstrainor wrote: »

I feel I did tighten them, but I worry that without the preload cap that I was doomed to failure?

I don't have a torque wrench with low enough calibration to torque the bolts, but my process was to tighten one a half turn, then switch to the other, and switch back and fourth until it was as tight as I thought was reasonable.

Is that a reasonable process? I followed a few guides on youtube.

EDIT: That image was just to show the spindle, non drive crank. You can ignore all the rest.

You need the cap. Put up a wanted add.

If it's shimano it's a "Hollowtech pre load bearing cap".

Handtighten it with plastic tool and then tighten up pinch bolts as per gcn etc

I know the fsa ones have two different size caps

Alanstrainor

Thanks for that! I'm even more annoyed at the last place for not tightening it enough for it to fall off now!

ford2600

Alanstrainor wrote: »

Thanks for that! I'm even more annoyed at the last place for not tightening it enough for it to fall off now!

It happens.

On fsa I used blue locative.

Shimano ones have never loosened on me.

saccades

Do not over tighten the pre-load, follow the torque setting otherwise you'll prematurely destroy the bearings.