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    Thru axle torque specifications

    The torque specification for a thru axle fork axle bolt is 12-16 Nm depending on the manufacturer.

    The front wheels of all four of my bikes have Surly Ice Cream Truck forks with Salsa Fat Conversion hubs http://salsacycles.com/components/ca...ub_front_150mm

    On two of my bikes, I overtightened the axle bolt. This caused the end cap to push into the inner race of the sealed cartridge bearing (both parts pictured below). This action ruined the bearing and made for some very noisy rides. The same thing happened on two identical bikes.

    Fortunately, installing a new drive side bearing ($5) fixed it, but I will be using a torque wrench from now on.

    I had thought that the hub bearings wore out after 1600 miles, but that is not the case because the non-drive side bearing was fine.

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    Last edited by commuter ebikes; 12-11-2017, 09:29 AM.

    #2
    By the way, I bought some drifts http://www.bikeman.com/TL4133.html and http://www.bikeman.com/TL4117.html for the bearing installation task. Because the axle (Part #2 in attached diagram) protrudes past the bearings, these drifts were useless for the task. The old bearings, however, served perfectly as drifts.

    I also managed to break the sealed bearing extractor http://www.bikeman.com/TL4104.html pictured below by using it improperly. It turns out that you have to grab the bearing at the bottom of the tool. If you drop the bearing extractor too far into the bearing, it ruins the tool.

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      #3
      Looking again at the exploded diagram, overtightening the axle bolt exerts too much pressure on Part #6 which compresses the inner race of Part #3, knocking the inner and outer races of Part #6 out of alignment.

      The manufacturer's instructions http://salsacycles.com/files/tech/78...t_Update_F.pdf do not list a torque spec for the front hub. The thru axle fork instructions http://surlybikes.com/uploads/downlo...structions.pdf say to "Follow the wheel manufacturer’s instructions for correct clamping of the wheel quick release". I used Google to arrive at the figure of 12-16 Nm which were the minimum and maximum values that I found.

      The Salsa Fat Conversion hubs came with QR skewers which is probably why the instructions don't list a torque spec. The Ice Cream Truck fork comes with an axle bolt and flange (silver hardware pictured below). The instructions say to use grease on the threads, but I use blue threadlocking compound because I won't risk the front wheel coming off at high speeds.

      Click image for larger version

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      Last edited by commuter ebikes; 12-11-2017, 09:39 AM.

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