1. Photo attached. Does the front chainring should be changed?


back side

enter image description here

  1. In case if yes. Almost all that exists for affordable prices is made from aluminum. Is it significantly weaker than from stainless steel?

  2. Any opinion about this chainring? For example https://www.aliexpress.com/item/33017750885.html

  • 1
    It slips, maybe once per 3-5 km. If check there is a light between chain and chainring, but the chain is relatively new (100-200 km). Also, I checked chain with "chain checker tool" and the chain seems to be fine.
    – Michael D
    May 3, 2020 at 7:47
  • 1
    The smaller chainring could be in need of replacement, but it’s hard to tell from this angle. The larger chainring looks worn but not too bad. Aluminum chainrings last 10–20Mm, steel chainrings should last pretty much forever.
    – Michael
    May 3, 2020 at 8:04
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    @Michael, the question was about large chainring. (I don't use the small one). What means 10-20Mm?
    – Michael D
    May 3, 2020 at 8:13
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    10 Mm is 10 million metres which is 10,000 kilometres or about 6200 miles. It is mostly a European thing. No big deal.
    – Criggie
    May 3, 2020 at 9:04
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    “The megameter (Mm) is a unit of length in the International System of Units, defined as 10^6 meters using the SI prefix system.”
    – Michael
    May 3, 2020 at 9:08

1 Answer 1


Yes that chainring is noticeably worn. When comparing the two photos, focus on the top and you can see the tips lean to the right in one shot and to the left in the other shot. Flipping between them looks like someone waving.

That, along with the slack test shows there is wear. Since you're getting chain slip, that wear shows its time for a new chainring.

As for Aluminium vs Steel vs other materials like carbon fibre, well its all a cost/weight/durability triangle. (the old Pick Any Two conundrum)

A related aside... If you never ever use the inner chainring, this might be a good time to consider a 1x setup so a narrow-wide single chainring.

Personally, I've seen chainrings in much worse state, working perfectly well. It comes down to your power, your chain state, and other variables like chainline/angle etc.

  • The reason that I have the second chainring is that my bolts are too long (I plan to change them). Thank you for narrow-wide suggestions! Any opinion regarding, the chainring on a link from aliexpress (aliexpress.com/item/33017750885.html)?
    – Michael D
    May 3, 2020 at 9:35
  • You said that the material question is a cost/weight/durability triangle, but you didn't say, which one you drop for aluminum/steel. I guess, aluminum drops the durability, steel drops the weight, while other materials drop the cost. Is that about correct? May 3, 2020 at 10:13
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    @MichaelD: It doesn’t say so but looks like it’s for a single chainring setup (no grooves to help with up/down shifting). Since that’s what you want it should be fine. Larger aluminium chainrings should last quite a while, especially if you replace the chain early (i.e. at the 0.75% stretch mark) enough.
    – Michael
    May 3, 2020 at 10:31
  • I don't see how the suggestion to switch to a 1× setup makes any sense. A 2× system is great, even when using it basically only as a narrow and fast 1× – but with still the small chainring there for unexpected situations. The advantages of 1× (lower weight or better options for rear suspension in heavy mountainbikes) really only play out when the bike has right from the start been designed as 1×. I'd rather suggest that maybe it's a good idea to use the small chainring a bit more! May 3, 2020 at 16:46
  • @leftaroundabout OP says they never-ever use the other chainring. And purchasing a new chainring is a chance to choose a narrow-wide one which would be incompatible with a front derailleur. Personally you can prise my triple from me when I'm dead !
    – Criggie
    May 3, 2020 at 20:18

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