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I am working on assembling a new boxed bike (aluminum Kona Libre), starting by tearing it completely down and making sure all components are properly installed, greased and adjusted. The headset felt notchy when I pulled it from the box, and sure enough, I found tons of little metal pellets in the headtube and embedded in the lower (non-sealed) bearings of the headset. When I opened the BB, I found the same pellets in the shell.

I’m cleaning the heck out of these areas before I reassemble to try to remove as many of them as possible, but I’m skeptical I’ll be able to get them all. What the heck are they? Am I right to feel concerned that these insidious little things will work their way back into my bearings?

metal pellets and grease on a towel metal pellets with M5 bolt for scale

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    Do the pellets respond to a magnet? ie, are they ferrous metal like steel ?
    – Criggie
    Jul 7, 2023 at 22:06
  • If those pellets are iron, you may be able to get the out of the frame using a magnet. Might be more effective than just shaking the frame. Jul 8, 2023 at 15:21

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My first instinct was that they’re little bits of weld splatter, but that doesn’t happen with aluminum (edit: it doesn’t really happen with TIG welding…splatter is mostly a stick welding problem) and there’s way too many of them. My next guess would be that they’re bead blasting media (essentially sandblasting on steroids). It would have been used to clean the welds and prep the outside of the frame for paint, but I guess someone at the factory forgot to shake the leftovers out before painting the thing.

As for possible solutions, I guess it depends on whether you’re confident you can get all the beads out of your frame yourself. They could be lodged in some awkward places and only come loose later on. Discuss with the manufacturer whether this is a reasonable expectation for you as the customer. The outcome of that conversation would determine whether you should ask for new bearings or an entire new frame. Perhaps even ask for multiple sets of bearings in case some leftover pellets kill the first set of replacement ones quickly. For environmental reasons, either of these solutions would be preferable over shipping the entire bike back and exchanging it for a fresh one. You have it all disassembled anyways.

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