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Shimano DA 7800 FD/RD use with 9 speed

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Shimano DA 7800 FD/RD use with 9 speed

Old 01-28-08, 04:13 PM
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Shimano DA 7800 FD/RD use with 9 speed

Can either the Shimano DA 7800 Fd or RD be used with my Shimano DA 7700 Cassette and
SRAM 9 speed hollow pin (89R) chain?

Basically, I now have a SRAM Rival 50/34 compact (10 speed) crank with Shimano DA
12/27 9 speed cassette.

Thus, RD capacity is 31T. I have the DA RD 7700 (short cage) which is rated at 29T
capacity. I've read all the capacity related posts on BF and it seems I can somewhat be okay
with exceeding RD capacity by 2T. If I do switch out to a med/long cage RD, I can not find
any suppliers of a DA RD-7700-GS (long cage model).

Thus, is 10 speed 7800 DA RD-7800-GS model compatible with (9 speed chain/cassette?
Or, do you know where I can find a 7700 (GS) RD?
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Old 01-28-08, 04:45 PM
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Sheldon Brown
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Originally Posted by bike_boy View Post
Can either the Shimano DA 7800 Fd or RD be used with my Shimano DA 7700 Cassette and
SRAM 9 speed hollow pin (89R) chain?

Basically, I now have a SRAM Rival 50/34 compact (10 speed) crank with Shimano DA
12/27 9 speed cassette.

Thus, RD capacity is 31T. I have the DA RD 7700 (short cage) which is rated at 29T
capacity. I've read all the capacity related posts on BF and it seems I can somewhat be okay
with exceeding RD capacity by 2T. If I do switch out to a med/long cage RD, I can not find
any suppliers of a DA RD-7700-GS (long cage model).

Thus, is 10 speed 7800 DA RD-7800-GS model compatible with (9 speed chain/cassette?
Or, do you know where I can find a 7700 (GS) RD?
Derailers generally don't care about how many speeds.

See: https://sheldonbrown.com/speeds for details on this.

Sheldon "No Problem" Brown
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Old 01-28-08, 07:46 PM
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Originally Posted by Sheldon Brown View Post
Derailers generally don't care about how many speeds.
Absolutely true for RDs, but you might consider using a 9-speed FD. The narrower-caged 10-speed FD may lead to increased chain rub and trimming. Shifting will be fine though.
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Old 01-28-08, 08:47 PM
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Thanks all for the info.
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