I just noticed these numbers on the inside of my Reynolds AR58 carbon wheel (see picture). The left paragraph seems to provide information about the product and manufacturing date/place. Does anybody know what the numbers/codes in the right paragraph mean?sticker with codes on the inside of the rim

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    ”UD” could stand for “unidirectional” (carbon fibers). Not sure what the other abbreviations mean but it could be the thickness of various carbon (or other fiber) layers.
    – Michael
    Jul 17, 2020 at 19:33

1 Answer 1


They're build QC tolerance numbers for side to side (lateral), up and down (radial), and offset (dish).

  • QC standing for?
    – piptoma
    Jul 18, 2020 at 5:00
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    @piptoma QC is "Quality Control" generally a stage between manufacturing/finishing and packing/distribution. Parts that don't meet QC get scrapped or sent back for rework.
    – Criggie
    Jul 18, 2020 at 6:05

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