What is the difference between KMC Z6 and KMC Z7 for 6 speed cassete?

On KMC site, both of them appear to be suitable for 6 speed bike.

KMC Z7: https://www.chainreactioncycles.com/il/en/kmc-z7-7-speed-chain/rp-prod51830

KMC Z6: https://www.chainreactioncycles.com/il/en/kmc-z6-6-speed-chain/rp-prod193013

1 Answer 1


Z6:enter image description here
from http://kmcchain.us/chain/z6-br-gy/

Z7:enter image description here
from http://kmcchain.us/chain/z7-2/

I think the only real difference is colour: Z6 is "silver" Z7 is "grey/brown" This is important to some people.

Note, Z6 was renamed from Z33, and Z7 was formerly called Z50.

I think your links show the wrong image for Z6 - the KMC site shows plain chain without slots, so CRC have a bad image.

  • 1
    On this page it shows chamfering for the Z6 which would probably make it lighter: kmcchain.com/en/product/bicycle-chain-z6-6-speed The different colours could be an indication of a different alloy, but not sure which one is better.
    – Michael
    May 11, 2020 at 7:49
  • @Michael the KMC site shows both have "chamfered internal plates" Given these are sub $10 USD or sub 5 UKP chains, they're not exactly high end.
    – Criggie
    May 11, 2020 at 9:13
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    Interesting, but only the Z6 photo on the linked (by me) page actually shows chamfered plates.
    – Michael
    May 11, 2020 at 9:24
  • Does narrow label on Z7 chain has any meaning?
    – Michael D
    May 11, 2020 at 16:30
  • 1
    @MichaelD I think that just means its 3/32" chain, instead of wider 1/8" chain. Both are 3/32" derailleur chain for 6~7 speed bikes.
    – Criggie
    May 11, 2020 at 20:38

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