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Compatibility question(7 posts)

Compatibility questioncheapskate
Jun 7, 2001 1:17 PM
Compatibility question...

Will the following work/index reasonably well together; New DA 9 speed downtube shifters, 2000 model 105 triple crankset, 8 speed DA rear der., and 8 speed SACHS freewheel?

I've heard/read discussion that a nine speed chain works well with an 8 speed freewheel, which would make me think the above should work.

Any thoughts? (Other than those including the phrases, "You don't know what you're doing!" "You're an idiot!", etc.)

re: Compatibility questionDave Hickey
Jun 7, 2001 2:59 PM
You will have no problem with the DA 8 speed rear and the DA 9 speed downtubes. They work fine together.
sure about that?...C-40
Jun 7, 2001 7:54 PM
I'm not a Shimano expert, since I use all Campy, but as I remember, shimano changed the DuraAce shifters and rear derailleur to be compatible with lower level shimano parts when 9 speed was introduced. Prior to that, the 8 speed rear derailleur and shifters would not work with lower level shimano components. I could see any shimano 9 speed shifter working with an Ultegra or lower level 8 speed derailleur, though.

It makes no sense to use 9 speed shifters with any 8 speed freewheel. The cog spacing is substantially different. The shifting would be lousy.

The duraace rear derailleur also does not have the capacity to be used with a triple crank, unless you don't use the small chainring.
Actually you have it backwardsDave Hickey
Jun 9, 2001 9:04 AM
Shimano changed all the other 9 speed models to have the same throw as Dura Ace. All Shimano 9 speed models will work with each other. And all 9 speed STI's with work with Dura Ace 8 speed.
I have two bikes that have 7700 9 Speed STI's with 8 speed cassettes( and Dura Ace 8 speed rear derailluers).
They shift perfectly. A Dura Ace nine speed rear derailluer will also work with 8 speed. If you attach the cable to the top of the rear derailluer bolt, instead of the bottom, it will shift 8 speed.
Shimano even explains this in their derailluer intructions.
YOU ! have it backwards...C-40
Jun 9, 2001 5:37 PM
According the September 9, 1996 issue of Velonews: "The DuraAce rear derailleur now has the same stroke as the Ultegra and every other derailleur in Shimano's line (since the inception of SIS, DuraAce's stroke length has been different than from all of Shimano's other road and mountain derailleurs)."

What you've stumbled across is an odd combination of an outdated 8 speed DA derailleur and cassette just happening to work with a 9 speed shifter. Normally, a 9 speed shifter should only be used with a 9 speed cassette.

The cog spacing on an 8 speed cassette is signifincatly larger than 9 speed (4.8mm vs. 4.32mm). The shifters (not the derailleur) are made to pull different amounts of cable for 8 or 9 speed use. To properly work an 8 speed cassette, you should be using 8 speed shifters (non DuraAce) with any Shimano derailleur EXCEPT an 8 speed DuraAce.

It's the amount of cable pull on the shifter that causes the movement of Shimano's derailleurs to coincide with 8 or 9 speed cog spacing.
Sorry, WrongDave Hickey
Jun 10, 2001 5:12 AM
Quit thinking in Campy terms. Read Duanes reply to the post about three above this one. He backs up what I say. If 8 speed is "outdated", why does Shimano's derailluer instructions explain how to use 9 speed shifters with 8 speed components? Ask a certified mechanic about the Dura Ace stroke. Shimano made all other derailluers have the same stroke as Dura Ace.
re: Compatibility questioncheapskate
Jun 10, 2001 2:27 PM
I'm inclined to believe those who say that 8 speed Dura-Ace rear der. (which sould work with a shimano 8 speed cogset) will work with 9 speed shifters, and that ANY Shimano 9 speed rear der. (which should also work with 9 speed shifters) can be made to work with shimano 8 speed cogset.

So, which combination should I use???

1. 9 speed DA downtube shifters.
105 triple crankset
8 speed SACHS cogset
8 speed DA rear der.

2 9 speed DA downtube shifters.
105 triple crankset
8 speed SACHS cogset
9 speed DA/Ult./105 rear der.

Also, should I use 8 speed or 9 speed chain?