8 sp w/9sp STI Technical question...



Rocket69

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Dec 23, 2003
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Hi all, this is for my winter "beater" bike... Will a 9 speed STI shift lever work with an OLD (circa 1994) 8 speed Dura Ace rear derailleur and 8 speed cog? This is for my “winter” bike, but the 8 speed STI lever is toast…

Thanks for the help…
 

alfeng

Well-Known Member
Jul 23, 2005
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Rocket69 said:
Hi all, this is for my winter "beater" bike... Will a 9 speed STI shift lever work with an OLD (circa 1994) 8 speed Dura Ace rear derailleur and 8 speed cog? This is for my “winter” bike, but the 8 speed STI lever is toast…

Thanks for the help…
The conventional wisdom states that YOUR older DA rear derailleur is not compatible with anything else in the Shimano line-up ...

That may-or-may-not be true ...

Your best bet is to simply try your 9-speed STI shifters with your older DA rear derailleur.

Shimano "provides" an alternate derailleur cable anchor "position B" at 9 o'clock. This effectively increases the pull ... try it if the "normal" cable anchoring position doesn't work ...

A 105/5500 rear derailleur (~$20US, used) will work with the alternate derailleur cable anchor position to index to your 8-speed cassette.

When in doubt, consider CAMPAGNOLO!
 

capwater

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Sep 15, 2003
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8 speed casette will not work with 9 speed shifter, diffrent lengths of cable pull.
 

alfeng

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Jul 23, 2005
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capwater said:
8 speed casette will not work with 9 speed shifter, diffrent lengths of cable pull.
Sorry, but this is an incorrect statement.

As noted, you can adjust the pull by the rear derailleur cable's anchor position.

Now, whether a vintage Dura Ace rear derailleur can be made to work may be a different matter because they were atypical ...

So, it will be a trial-and-error matter.
 

ccdisce

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Apr 14, 2006
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I agree with what the other members have suggested, give it a try.

If the DA8 STI brifters are not broken internally, a clean and lube should be able to get them working like new again. The installation kit that came with the 2 sets DA8 brifters that I installed on my builds, tells how to do this and the kit also provide 2 'tools' to help with the partial dis-assembly and re-assembly.

Rocket69 said:
Hi all, this is for my winter "beater" bike... Will a 9 speed STI shift lever work with an OLD (circa 1994) 8 speed Dura Ace rear derailleur and 8 speed cog? This is for my “winter” bike, but the 8 speed STI lever is toast…

Thanks for the help…
 

John M

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Jun 21, 2005
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Rocket69 said:
Hi all, this is for my winter "beater" bike... Will a 9 speed STI shift lever work with an OLD (circa 1994) 8 speed Dura Ace rear derailleur and 8 speed cog? This is for my “winter” bike, but the 8 speed STI lever is toast…

Thanks for the help…

The answer to your question is YES. But only becuase you have an old DA rear derailleur. The 8s DA RDs used a different pull ratio than other shimano RDs. The combination of a current S9 shifter and and OLD 8s Dura Ace RD should equal the spacing of Shimano 8s WITHOUT modification of the cable routing.

What alfeng is referring to on newer DA derailleurs is an alternate cable routing that allows the new RD to be used with OLD shifters. He is correct that the alternate cable routing will allow a current Shimano RD to index 8s with the alternate cable routing with OLD 8s shifters.

I would get the 9s shifter, use it as you propose and when the cassette/chain are shot, change to 9s cassette and chain and a new Shimano RD and you will have a 9s drivetrain.