Chain Size 9/10/11

[nigelnightmare]

Can someone tell me why Chains for 9/10 & 11 speed are all the same size now?
I.E.
1/2" x 11/128" with 6.57-6.6mm pin length.
As I was under the impression that 9 speed was 9/32"

[NickJP]

Can someone tell me why Chains for 9/10 & 11 speed are all the same size now?
I.E.
1/2" x 11/128" with 6.57-6.6mm pin length.
As I was under the impression that 9 speed was 9/32"

They're not all the same. Nominal external width across the rivets:

12-speed: 5.3 mm
11-speed: 5.5 mm
10-speed: 5.9 to 6.2 mm
9-speed: 6.6 to 6.8 mm

[Brucey]

11/128" is the nominal internal width of the chain, just a bit smaller than 3/32". 9/10/11s chains are about the same internal width as one another, not the same external width.

cheers

[nigelnightmare]

Thank you both for that.
Brucey, I didn't realise that the size was the internal dimension.
If they've got the same internal dimension, Why are the chainrings different?
I can understand the cassette being thinner & closer spaced (otherwise the wheel would get wider), but not the chainrings.

[Brucey]

I think the chainring differences are at least as much as anything else to do with the chainring spacing; if you try and use 9s chainrings with 11s chain , you run the risk that the chain will just skate on top of the small chainring. 10s and 11s big chainrings are dished such that the chain is forced onto the small chainring yet it is still able to operate cross-chained (small-small) without tickling the edge of the big ring too badly.

Note also that the chain internal size is nominal; there may be small differences that they don't talk about.

cheers

[nigelnightmare]

OK. Thanks.