An electronics supply store will sell you 1/16" shrink tube. Clip 1/2" of fuzz off pipe cleaner end down to the wire center and slip a 1" piece of shrink tube about 1/2 way onto pipe cleaner wire end. Heat the shrink tube a bit with match or heat gun and watch it shrink down to small enough size to cling to pipe cleaner wire and protect the wheel bore when inserting the pipe cleaner.
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