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The Shimano Altus FC-M311 crank comes pre-greased with four generous drops of grease on one side of the crank's thread (the yellow circles in the image), but it's unclear where it should be used: on the square holes or the threads?

I didn't find anything in the Shimano documentation about this subject and Parktool advice against using grease for a square tapered spindle.

Related: Should square taper cranks be greased before installation?

Pre greased shimano FC-M311

2 Answers 2

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The dots of grease in question are there to lubricate the bolt shoulder, so that friction there is less of a factor in how much thread preload is achieved for a given torque input. Leave it in place, or borrow some of it to also lubricate the bolt threads.

The bolt threads are the really critical spot to always lubricate thoroughly, but the shoulder is also important, particularly when the parts are new and the bolt and crank need smooshing into their final embrace with each other.

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    "smooshing into their final embrace with each other." Very poetic. When my girlfriend again frowns upon my constant stream of bike projects, I'm going to tell her I'm working on my romance!
    – Jeff
    Apr 15 at 1:30
  • Since those are really generous "dots" of grease, would you suggest taking half for the corresponding bolt shoulder and thread area on the NDS crankarm?
    – Armand
    Apr 15 at 20:05
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    @Armand new shimano cranks come with it on both arms. i think for the most part it doesn't really matter what you do as long as you end up with at least a light coating of it. Apr 15 at 20:38
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It's always been a standard to grease any metal surface which touches another metal surface.

A massive amount of grease is unnecessary for any contact surface except for ball bearings.

There was some debate about greasing tapered spindles, potentially forcing it too far, but torque specs answered how tight to make it.

I would grease every thread, and make sure to have a rag when the excess squirts out!

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  • That might be an ok rule of thumb, but some screws should not be greased on their thread. Ex. you should not put grease on v-brake link fixing bolt (ref Parktool install guide)
    – Selusiac
    Apr 15 at 22:07

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