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Looseness in BBSHD crank

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    Looseness in BBSHD crank

    There has been some play in the crank of my BBSHD since I got it. I had a mechanic check the crank itself, which didn’t change it so it must be internal. Is this normal? It doesn’t seem to be getting much worse, but worries me about wear and how long it will hold up. Just finished a 200-mile multi-day ride and want to resolve this before planning a longer one.

    #2
    In the spindle or axle (side to side) - not the crank arms, correct?

    If so, perhaps this video will help:

    2nd build, 2018 Crust Scapegoat, BBS02 or BBSHD, Rohloff IGH
    3rd build, 2018 Crust Evasion step-thru, BBS02, Shimano Nexus INTER-3 IGH
    4th build, 2016 Salsa Marrakesh flatbar frameset, BBSHD, Alfine 8 IGH

    Visit the forum knowledge base

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      #3
      Thanks for the reply and video. It might be end play - I think the crank arms are ok. It feels like a little shift of slack when you pedal. There is also a clunk when you resume pedaling when PAS is engaged, the higher the level the stronger the clunk. Will have the crank arm checked again but think it’s internal. Is wear a worry if left with the end-play?

      Comment


        #4
        I'm not sure, but I don't think wear is a worry unless parts are missing - which doesn't seem your situation.A rocking, twist-able axle play would concern me.
        2nd build, 2018 Crust Scapegoat, BBS02 or BBSHD, Rohloff IGH
        3rd build, 2018 Crust Evasion step-thru, BBS02, Shimano Nexus INTER-3 IGH
        4th build, 2016 Salsa Marrakesh flatbar frameset, BBSHD, Alfine 8 IGH

        Visit the forum knowledge base

        Comment


          #5
          Yes it is rocking! Now that I examine it I see the gap at the arrow (see attached photo) close and open about two millimeters. The housing is loose, allowing the axle to rock up and down. Seems like it will take more than just tightening the bolt in front of it.

          Comment


            #6
            Sigh, gonna start over again - but that's ok.

            Your last picture indicates an entirely different, but less concerning issue. There's a large steel lock ring under that aluminum, decorative ring with the white "Bafang" logo that likely needs to be tightened up a LOT (60 foot pounds torque).

            The best way to do this is with the special socket, after removing the left crank arm.
            Last edited by ncrkd; 08-08-2019, 08:46 PM.
            2nd build, 2018 Crust Scapegoat, BBS02 or BBSHD, Rohloff IGH
            3rd build, 2018 Crust Evasion step-thru, BBS02, Shimano Nexus INTER-3 IGH
            4th build, 2016 Salsa Marrakesh flatbar frameset, BBSHD, Alfine 8 IGH

            Visit the forum knowledge base

            Comment


              #7
              Yes that’s it. Regret that I didn’t identify the problem correctly from the start, and that I made you start over again. It is being fixed now hopefully with no consequences from being used in that loose condition for a long distance. Thank you for your help.

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                #8
                No issue, and a loose locknut is a better situation to have than something internal to the motor. Hoping that's all it is.
                Last edited by ncrkd; 08-10-2019, 06:53 AM.
                2nd build, 2018 Crust Scapegoat, BBS02 or BBSHD, Rohloff IGH
                3rd build, 2018 Crust Evasion step-thru, BBS02, Shimano Nexus INTER-3 IGH
                4th build, 2016 Salsa Marrakesh flatbar frameset, BBSHD, Alfine 8 IGH

                Visit the forum knowledge base

                Comment


                  #9
                  I am embarrassed that I’d hadn’t noticed where the slackness was for all those miles. At first it would not have been obvious. I had the mechanic that installed it tighten the crankset since I thought that was the problem, and he didn’t notice the locknut being loose either. He will also check that the rocking hasn’t worn the bearings in the crankset. I’ll mention the 60 ft pounds torque when I pick it up today.

                  Comment


                    #10
                    If he says he couldn't check the torque, I wouldn't be surprised. It's darn near impossible to do without the specialized socket.

                    "Real tight" by hand with a hook wrench should be good enough.

                    P.S. if Port Angeles is where I think it is - well, it looks like a beautiful place to reside.
                    2nd build, 2018 Crust Scapegoat, BBS02 or BBSHD, Rohloff IGH
                    3rd build, 2018 Crust Evasion step-thru, BBS02, Shimano Nexus INTER-3 IGH
                    4th build, 2016 Salsa Marrakesh flatbar frameset, BBSHD, Alfine 8 IGH

                    Visit the forum knowledge base

                    Comment


                      #11
                      Mechanic wasn’t there when I picked it up, but all the play is gone for the first time since I’ve had it, so it was never tight enough initially. I’ll keep an eye on it and assume most bike shops will have the hook wrench if needed. There is about 2 mm end play in the crank but that seems ok. Port Angeles is a nice place to reside, on the Straits of Juan de Fuca across from Victoria, BC. Planning a 300-mile loop up there on the bike in a few weeks.

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