shimano 9 chain compatible with 8 spd rings?

[02GF74]

ok, similar question to yesterday.

I have 8 and 9 speed systems, fortunately all shimano, so wantto reduce the number of spares. Seeing a 8 speed parts are becoming scarcer than 9 speed, e.g. not many 8 speed rear derailluers about, I intend to slowly change over to as many 9 speed parts as poss.

In order not to have 2 different types of chain lying round, here is the question.

Will a shimano 9 speed chain work as well as an 8 speed chain on a 8 speed set up? (8 speed chaing rings, cassette and shfters).

Anyone successfully using this?

 

[fossyant]

Yep - I'm running a DA 9 speed chain on DA 8 groupo !

 

[briank]

Me too.
Regularly (annually) move chain from DA 9 best bike to DA 8 winter one. No probs.

 

[andy_wrx]

9sp derailleurs will work perfectly happily on a 8sp system.

In the days of 8sp Sora, it was a common marketing thing (Spesh Allez, TRek 1000 for example) to try to sell you their bike over the competition by saying it had an 'upgraded' Tiagra rear mech.

The mechs don't 'know' how many speeds there are.
The shifters do, they pull a different amount of cable which makes the mech move sideways the required amount for the gap between the cassette cogs.

And the inner size of the chain is the same, so a 8sp or 9sp chain will ride just as happily on the jockey wheels or chainrings.