What is the purpose of the LH Hollowtech lock spacer?

02gf74

As per title, what does this small spacer (1 mm thick) do?

And what would happen if it is missing?

When the bolts are done up quite tight, the gap in the crank is still big enough for the spacer to move so I don't think it is there to stop overtightening the crank.

It has a tiny pin, not easily seen in picture that I can't figure out the purpose.

Part 9 in orange below

nicklouse

stop the arm falling off.

Chunkers1980

It is there as Nick says to stop the crank arm falling off. I'd add to that there's only a need for it if the bolts are undone - it's really a little superfluous. It should be aligned with a hole (indent) on the crank side axel. The little bit of pertruding metal works to keep it flicked down so if you take it off it only goes one way back on.

TBH - it's of little use if the cranks are setup correctly - just a fail safe.

02gf74

hmmm, really had to see how a tiny pin, maybe 0.5 mm diameter, is gonna stop the crank from falling off, especially since there is a large hollow bolt that would need to unscrew as well..

Anyways, since I am missing that piece, I will use locktite on the bolts. 8)

Chunkers1980

What?

It's the plastic bit that would stop them coming apart - it works too as you always need to lift it to get the cranks off.

Hope you don't mean the plastic pre-tensioner? You need that to set pre-load.

No need for loctit either.

nicklouse

02GF74 wrote:

hmmm, really had to see how a tiny pin, maybe 0.5 mm diameter, is gonna stop the crank from falling off, especially since there is a large hollow bolt that would need to unscrew as well..

Anyways, since I am missing that piece, I will use locktite on the bolts. 8)

dont you will have problems removing them.

just torque them up correctly.

Older versions did not come with the lock tab.

and you have never tried removing an arm without disengaging the lock tab have you.

Anonymous

My Saint cranks never had the spacer thing, and it is a total pain in the backside. They often explode, taking large swathes of forestry with them.

lesz42

yeehaamcgee wrote:

My Saint cranks never had the spacer thing, and it is a total pain in the backside. They often explode, taking large swathes of forestry with them.

happened a few times al llandegla, proof is were have all the trees gone?

and explains Tunguska event, was a Shimano Prototype

Mooose

I found what it was for after ripping the crank arm off with it still in place and finding a (now bent) little pin had been causing me the grief. Believe me despite it's microscopic proportions that little pin is quite effective at holding the crank arm on when all the bolts are loosened!