I have an older aluminum rear wheel that has a continuous line of hairline cracks. The hairline cracks proceed in a circle around the wheel on both sides of the wheel. The front wheel does not display this pattern.

Wheel on trainer with a zoomed in picture of hairline cracks An alternative angle

When I search for "cracked wheels" in google or previous questions here on this site, I see damage that appears far more obvious than these subtle lines. On this wheel, none of the spoke holes have any apparent damage and the cracks do not appear to be deep. It could just be paint but I've never seen this before. They make me uneasy as I'm unsure if they are safe.

Are these cracks dangerous to the integrity of the wheel?

I'm referring to the green line.

enter image description here

  • Is your wheel true or does it need to be re-trued frequently?
    – Criggie
    Commented Aug 5, 2023 at 4:38
  • @criggie I'll have to admit I don't know much about true wheels. I've never had this wheel trued and I don't have a truing device but it is at least a little off as it can rub unevenly against misadjusted brake pads, but on normal usage it's not problematic such that I've sought to fix it. Commented Aug 6, 2023 at 17:05
  • I just checked the wheel and visually it has some deviation while spinning but again not so out of true that any of the spokes feel loose or that it causes noticable problems while riding. It's a cheap wheel so I've never worried about it (perhaps erroneously) Commented Aug 6, 2023 at 17:11

1 Answer 1


Not an answer, but I can't post a pic in a comment. Can you please clarify which lines you're concerned over?

enter image description here

  • 3
    Let’s wait for OP to confirm, but I’m pretty sure they are referring to the green line. It’s that band of cracked/crinkly-looking stuff that runs continuously around the rim.
    – MaplePanda
    Commented Aug 5, 2023 at 5:31
  • 1
    @MaplePanda concur that's plausible - that's a reinforcing rib added separately to the rim's extrusion. On confirmation I'll delete this as not an answer.
    – Criggie
    Commented Aug 5, 2023 at 6:09
  • Yes, thank you for clarifying! @maplepanda was correct that I'm referring to the green line. Commented Aug 6, 2023 at 17:02

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