Hello,
I am looking for some mechanical help.
My brother-in-law is planning to use his beautiful old DuraAce
8 speed rear derailleur on his tri-bike, together with a 9 speed
cassette and bar end shifters.
Is it possible to set up the bike in such a way that he can use
all 9 gears?
Thanks for any advice on this.
Matthias
8speed/9speed combo possible?
Mon, 08/21/2006 - 5:38am
Mon, 08/21/2006 - 6:08am
#1
spacing issues
would need friction shifters.
don
Mon, 08/21/2006 - 7:12am
#2
the any speed rear derailleur
"Matthias, the rear derailleur will work with any cassette withing a certain capacity. Capacity meaning taking the difference of the tooth count of the smallest cog in the cassette and subtracting it from the largest tooth count in the cassette.
The short story is, for tri-bikes, the range of road bike cassettes used, whether it be 8/9 or 10 speed, should be just fine with that derailleur. The length of chain and maximum amount of derailleur travel used should not vary much between your in law's old and new setup.
Incidentally, moving to a triple chain ring setup or using a mountain bike cassette will require a ""long cage"" derailleur which has a greater capacity.
As for the bar end shifters, if they are indexed, meaning the shifter moves the cable and derailleur a prescribed length, between clicks, then they will need to be indexed for a 9 speed cassette. In other words you will need 9 speed specific indexed shifters.
If the bar end shifters work relying on your hand for click-free proper gear adjustment, then these ""friction"" shifters will work just fine for 8 or 9 speed cassettes.
"
Mon, 08/21/2006 - 7:30am
#3
If the shifters and cassette are both 9 speed, it will work fine.
Shimano 8 speed and later derailleurs are completely interchangeable.
Mon, 08/21/2006 - 10:06am
#4
Dura-Ace 8-speed was different
I don't think this will work with index shifting: http://www.sheldonbrown.com/dura-ace.html
Mon, 08/21/2006 - 10:14am
#5
again...
...need to go with friction shifters if you're going to use a combination of 8sp and 9sp parts. spacing is off on the sprockets, geometry is different on derailleur so trying to use a 9sp index shifter on a derailleur designed for 8sp is only setting yourself up for misery (even if you THINK it works when you're at home testing it out).
don
Mon, 08/21/2006 - 10:54am
#6
perhaps
"Edit: per Sheldon Brown's site, ""The major difference between pre-1997 Dura-Ace and the rest of the Shimano lines is the cable travel of the rear derailer. Old Dura-Ace used a shorter amount of cable travel per shift. This has to do with the geometry of the cable attachment.""
So perhaps, Don is correct afterall. This is assuming the bar end shifters are indexed. I forgot about the exclusivity of older Dura-Ace components. I would still give it a try using the existing Dura-ace rear derailleur before plunking down more coin for a new derailleur."
Mon, 08/21/2006 - 3:53pm
#7
bar end shifters should have friction option...
...is there a d-ring on the rear shifter you can switch to friction? if so, just need to set inside/outside limit and route the cable appropriately on deralleur arm.
don
Tue, 08/22/2006 - 9:15am
#8
Always match number of gears on the shifter with the cassette!
"Don--
You can mix 8 & 9 speed derailleurs & shifters with no problem (Dura Ace may be different). You can mix rear derailleurs made for 8 speed with 7, 9, or 10 speed cassettes, no problem. I've done these kind of things with no loss in shifting accuracy whatsoever. You can even use 9 speed Shimano cassettes with 9 speed campy shifters/derailleurs (been there, done it, no problem).
But you can't mix a Y-speed cassette with an X-speed shifter. The ""clicks"" on the shifter are spaced to pull just enough cable to match the spacing between the cassette cogs. And the spacing between the cassette cogs is different from 8, to 9, to 10 speed cassettes. So if you have an X-speed shifter, you have to get an X-speed cassette.
Rich"
Mon, 08/21/2006 - 10:54am
#9
No, you're right. I forgot - has to be 7700 (9sp) Dura-Ace or later. I thought the dumb Dura-Ace incompatibility ended with 7400, but apparently 7402 was similarly afflicted. Ugh.
Mon, 08/21/2006 - 3:26pm
#10
nm
nm
Tue, 08/22/2006 - 3:00pm
#11
Thanks!
Thanks for all the very useful information!
I will pass it on and keep you posted how it
worked out, if you are interested.
Cheers,
Matthias
