9 speed chain on 8 speed bike

[larrypac]

All of my bikes are 7 or 8 speed and sometime in the past I bought a 9 speed chain for some unremembered reason. is there any reason not to use it on an 8 speed bike?

[Nutribun]

None at all. Definitely you can use your 9spd chain to your 8spd drivetrain.

[ReapThaWhirlwind]

People say that this is compatible, but I find that using a higher speed chain on a lower speed cassette especially causes complications in the fact that the indexing is much stricter. I don't like the experience at all, and I don't feel the shifting improves at all really.

I would only recommend it as a last resort. I could never say it's a performance boost of any kind.

[Jesper]

No problem using a "9 speed" chain on an 8 speed cassette. On the other hand I would not use a 9 speed chain on a 10 speed cassette. That is where the tolerances between chain width and cog spacing is tighter and not the other way around. If you are trying to use a 9 speed chain on a 7 speed you might experience "skating" if you are a "slow"/inexperienced shifter and are not aware of the difference required to provide proper shifting. This is where those who are not adept at friction shifting fail because they are not used to actually shifting and expect everything to work in lock step to the indexing. Just like those who have never driven a standard manual shift vehicle over an automatic. I have readily skipped 2 speeds (compared to chain vs cassette) with chain being designed for a higher capacity cassette. Unfortunately, many people do not know how to shift in the first place regardless of friction or indexed (not electronic!) shifting, and often wait too late before shifting causing undue strain on the drivetrain. An exception is when you start to get to "noncompact" clusters of 6 or less cogs. The spacing between cogs is significantly more than with newer compact clusters. Before buying new chains just try it out since you already have the parts inhand. If everything works okay then fine if not then try a more suitable set-up. Why waste money if you don't need to. Experimentation is the true means of discovery. No experimentation and you will never know.
Fill us in on the details should you use your current parts and how they function.l; but remember you must know how to and when to shift to actually determine if everything is compatible. My most extreme case was using a ln 8 speed chain on a 5 speed cluster wh8ch was not an issue except for an improperly built freewheel with incorrect spacers between cogs which caused "skating" between the improperly spaced cogs. Anyone with my experience (40yrs) of friction will easily adapt; the rest will be boggled by the inadequacy of pampered index shifting used to nothing more than a click and shift. Certainly, if you want the most trouble free shifting, you should match as best as possible the cassette with the chain, but even then it is far from being foolproof and friction shifting knowledge will trump those without it. I doubt that most casual cyclists using indexing could outshift me while I use friction shifting, especially on hilly terrain that they are unfamiliar with. Learning the basics will help when using the more complex systems.