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Thread: 1980 R100/T Front End Question

  1. #1
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    1980 R100/T Front End Question

    I'm rebuilding my front end. After removing the lower sliding tubes, I noticed the holes in the upper standing tubes are at different angles(see photo).

    forks.jpg

    The tube holes on the left are aimed directly to the back. While the holes on the tube to the right are aimed almost but not quite to the front.

    My question is, does this mater? is there a correct position for the holes?

    Thx...

  2. #2
    Administrator 20774's Avatar
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    Welcome to the forum!

    I've read that the holes should be pointed at each other.

    My engineering recommendation is that the holes should be pointed either to the left or to the right...at or away from each other shouldn't matter. The reason is that since the tube is bending fore-aft as a result of road input to the tire and hence the axle, that puts the highest stresses on the front or back side of the tube. The line running down the middle of the tubes on either side will be at the neutral axis which has typically zero stress during pure bending. Since holes are stress concentrations, typically raising the local stress levels by a factor of 3, having the holes located in the least stressed region makes the most sense.

    In the end, it probably doesn't really matter that much if the stresses are low enough (they probably are) and your tubes seemed to have suffering nothing in the arrangement. But if you can help the situation, why not!!
    Kurt -- Forum Administrator ---> Resources and Links Thread <---
    '78 R100/7 & '69 R69S & '52 R25/2
    mine-ineye-deatheah-pielayah-jooa-kalayus. oolah-minane-hay-meeriah-kal-oyus-algay-a-thaykin', buddy!

  3. #3
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    Mar 2014
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    Makes sense, thanks for the info...

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