8 and 9 speed intercompatibility

Wondering about mixing Shimano 8 and 9 speed parts, or mixing with stuff from 3rd parties, like
extra large chainrings (60 teeth and more).

Rear derailleur indexing is said to be the trickiest part when you do 8/9 mixing, but how about
chain, sprockets and chainwheels? What if you have a crankset designed for 8 speed chain, or just a
single chainring measured for 8 (with others for 9 speed) in an otherwise 9 speed system (chain,
rear deraileur)? Some people claim it fits just fine, can you expect any problems because the fit
is not perfect (too wide chainrings for the chain etc) - increased wear, chain slippage, or
something else?

--
Risto Varanka | http://www.helsinki.fi/~rvaranka/ varis at no spam please iki fi

 

In article <[email protected]>,
<[email protected]i> wrote:
>Wondering about mixing Shimano 8 and 9 speed parts, or mixing with stuff from 3rd parties, like
>extra large chainrings (60 teeth and more).
>
>Rear derailleur indexing is said to be the trickiest part when you do 8/9 mixing,

Actually Shimano (non-Dura Ace) 8 and 9 speed rear derailleurs interchange quite well. The main
thing you want if you wish to avoid trouble is:

1. 9s shifters
2. 9s chain
3. 9s cog set

The rest is optional.

> but how about chain, sprockets and chainwheels? What if you have a crankset designed for 8 speed
> chain, or just a single chainring measured for 8 (with others for 9 speed) in an otherwise 9 speed
> system (chain, rear deraileur)?

No problem.

> Some people claim it fits just fine, can you expect any problems because the fit is not perfect
> (too wide chainrings for the chain etc) - increased wear, chain slippage, or something else?

No, nothing so awful as that. The 9s chainrings when ramped & pinned to match each other, can make
the front shifting a little smoother. But if you don't use 9s chainrings, it will still shift quite
adequately - front derailleurs already worked quite well before ramped rings came around.

60-tooth chainrings do present challenges to front shifting and chain line, but that has nothing to
do with whether they are 9s or not.

I think a 56-tooth ring is about as big as you can go without considerable tinkering necessary to
get good shifting, often that means taking the front derailleur to the bench grinder. Even with a
56 there are some bikes it won't work well on due to chain line problems or braze-on front
derailleur mounts.

Of course if you have only one ring then it gets a lot easier, and if you have only one ring then
the issue of ramped and pinned 9s chainrings is completely irrelevant.

--Paul

 

<[email protected]> wrote in message
news:[email protected]...
> Wondering about mixing Shimano 8 and 9 speed parts, or
mixing with
> stuff from 3rd parties, like extra large chainrings (60
teeth and
> more).
>
> Rear derailleur indexing is said to be the trickiest part
when you
> do 8/9 mixing, but how about chain, sprockets and
chainwheels?
> What if you have a crankset designed for 8 speed chain, or
just a
> single chainring measured for 8 (with others for 9 speed)
in an
> otherwise 9 speed system (chain, rear deraileur)? Some
people
> claim it fits just fine, can you expect any problems
because the
> fit is not perfect (too wide chainrings for the chain
etc) -
> increased wear, chain slippage, or something else?
>
> --
> Risto Varanka | http://www.helsinki.fi/~rvaranka/ varis at no spam please iki fi

FWIW - my wife's bike currently has an RSX seven speed compact triple crankset and RSX dérailleurs,
with nine speed Shimano 105 shifters and cassette, and a nine speed chain. The combination works
really well......