Can I use KMC Z7 chaing (1/2 x 3/32) on 8 speed cassete Sunrace MFM-56?

When I changed the old chain with KMC Z7, the smallest sprocket and the largest are fine.

But in the between the shifting is not smooth and something feels not right (slipping/ skiping). NOTE: chain and cassete are both new.

Below are picture of KMC Z7 and Sunrace MFM-56.

KMC Z7 Sunrace MFM-56

P.S. There is also Z8 chain on KMC website. But it seems to me, that it absolutely the same size (1/2 x 3/32, pin=7.3mm).


I tried a new KMC Z8 chain with width of 7.1mm. But it didn't provide a significant improvement. Maybe there is something wrong with a cassete ( a fake one?).

  • I agree, but he both chain and cassette are new.
    – Michael D
    Sep 23, 2020 at 21:28

1 Answer 1


Z7 is one of if not the only 7-speed specific chains still made. It won't work right on 8-speed.

  • But the Z8 has the same sizes? What the difference?
    – Michael D
    Sep 23, 2020 at 21:27
  • 2
    There's ambiguity in what one reads about this and I don't claim to know the chronology or have done all the measuring needed to see how it actually works firsthand, but basically in practice 7.1mm corresponds to 8-speed more and 7.3 to 7-speed. KMC lists the 7.3mm Missinglink as being compatible with a bunch of 8-speed chains, but then you go to put it on one and it's usually totally sloppy and the 7.1 fits better. Measure a bunch of 8-speed pin lengths and you'll be seeing 7.1-7.2, and I think the Z7 will be 7.3-7.4. Sep 23, 2020 at 21:53
  • 2
    According to Wikipedia 6, 7 and 8 speed chains have the same dimensions: en.wikipedia.org/wiki/Bicycle_chain
    – Carel
    Sep 24, 2020 at 18:59
  • @Carel I saw that. It's wrong. 6 speed chains originally had longer pins than 7.3/7.1 and 7-speed specific chains are not 7.1mm. Something went wrong in the data they're presenting. Look at old Sutherlands editions and you'll see. Sep 24, 2020 at 19:47
  • @NathanKnutson KMC Z8.3 writes, that it has a 7.3 mm pin.... neweracycle.com/kmc-z8-3-for-6-7-8-speed-chain I will try to buy a Shimano HG-40, which should be fine for 8 speed bike and will update... Also at cassette specs (sunrace.com/files/catalog/files/475/…) it says, that it should be compatible for 7.1-7.3 mm pin...
    – Michael D
    Sep 28, 2020 at 20:16

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