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I'm in the process of replacing crankset and bottom bracket on my road bike - square taper type spindle. Bike is only four years old and bought from new, so all original parts with threads in good condition etc.

Trying to thread crank puller tool into cranks but can't seem to get it to screw in - obviously don't want to force it as it seems like hand tightening should be sufficient. Looks to be the correct size and cleaned & greased the threads of both the tool and the cranks.

Is there a particular technique to doing this or is it really just a case of turning clockwise and it starts to engage with the crank thread?

May be an age old question, but never done this before and don't want to risk damaging tools and/or components. Any suggestions appreciated.

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    Are the crank arm painted? Say black vs polished aluminum finish. I have run in to arm where the threads have paint in them. A toothbrush size wire brush removed enough to get it started, the tool removed the rest.
    – mikes
    Commented Jul 9, 2020 at 9:43
  • Yes, actually they are finished in black - I did wonder whether the slight lip of black paint before the threads start is causing the issue. Will give that a try
    – Tom Mayfield
    Commented Jul 9, 2020 at 10:54

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Try removing the black finish with a small wire brush. It may be anondized and difficult to remove. Regrease both sets of threads. I always start by giving the tool a quarter turn or so to the left before proceeding to the right. Seems to line the threads up and helps prevent cross threading.

In this area of the bike (cranks, bottom bracket) it's best practice to at first hand thread the tool, bottom bracket cup, crank fixing bolt, etc as a measure to prevent cross threading. Regarding the crank puller: the outer nut needs to be threaded fully into the crank arm good and tight before you attempt to wind in the center bolt that pulls the crank arm. You risk damaging the crank arm threads if the tool isn't fully engaged with the crank arm. Thus "hand tight" as you described would be risky. A common error related to this is not having that center bolt of the crank puller backed out enough and so it bottoms out on the square taper before the outer nut is fully engaged in the crank arm. Same deal: the crank arm threads strip or become damaged making subsequent removal difficult or impossible without ruining the crank arm

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it seems like hand tightening should be sufficient.

It isn't. You should tighten it with a wrench. You don't need a ton of torque, but it typically takes more than you can deliver with hand tightening. You want the tool well engaged, ideally bottomed out, and you often can't get there hand tightening even on a brand new crank.

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