Dura Ace 7700 9-speed and Dura Ace rd7402
11-05-20, 04:03 AM
#1
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Dura Ace 7700 9-speed and Dura Ace rd7402
Hey guys...
I am in the midst of building a bike and was wondering can a 7402 rear derailleur do 9 speed shifting? I mean rd-7402 is only meant for 8 speed, rite?
I am choosing 7402 cos I kinda the the 'dura ace' sign in black setting and 7700's and 7800's rear derailleur is kinda plain...hehehe...
Please share some ideas...
Many thanks in advance...
I am in the midst of building a bike and was wondering can a 7402 rear derailleur do 9 speed shifting? I mean rd-7402 is only meant for 8 speed, rite?
I am choosing 7402 cos I kinda the the 'dura ace' sign in black setting and 7700's and 7800's rear derailleur is kinda plain...hehehe...
Please share some ideas...
Many thanks in advance...
11-05-20, 07:18 AM
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IIRC the RD will not work above 8 speed. You can use the 9 speed shifters with it but not a 9 speed cassette.
11-05-20, 07:41 AM
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Back when Shimano 9 speed came out it was a common upgrade to use 9 speed shifters with a 7400 series rear derailleur on an 8 speed cassette. This setup works perfectly except that you have one extra click that you can't use. For a 9 speed cassette, this won't work
11-05-20, 07:45 AM
#4
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The RD-74xx series has a higher ratio than Shimano's older SIS RDs. i.e; it moves more per mm of cable pull than others SIS.
So with a 9 speed SIS shifter it will move too much for a 9 sp cassette spacing but will be correct for a 8 sp cassette. If you use a Shimano road 10 sp shifter (except ST-4700 Tiagra) the RD-74xx will index properly for a 9 sp cassette. This assumes a Shimano compatible cassette in both cases. It was kind of designed this way to provide a certain path of usability for older system parts.
So with a 9 speed SIS shifter it will move too much for a 9 sp cassette spacing but will be correct for a 8 sp cassette. If you use a Shimano road 10 sp shifter (except ST-4700 Tiagra) the RD-74xx will index properly for a 9 sp cassette. This assumes a Shimano compatible cassette in both cases. It was kind of designed this way to provide a certain path of usability for older system parts.
11-05-20, 08:19 AM
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The RD-74xx series has a higher ratio than Shimano's older SIS RDs. i.e; it moves more per mm of cable pull than others SIS.
So with a 9 speed SIS shifter it will move too much for a 9 sp cassette spacing but will be correct for a 8 sp cassette. If you use a Shimano road 10 sp shifter (except ST-4700 Tiagra) the RD-74xx will index properly for a 9 sp cassette. This assumes a Shimano compatible cassette in both cases. It was kind of designed this way to provide a certain path of usability for older system parts.
So with a 9 speed SIS shifter it will move too much for a 9 sp cassette spacing but will be correct for a 8 sp cassette. If you use a Shimano road 10 sp shifter (except ST-4700 Tiagra) the RD-74xx will index properly for a 9 sp cassette. This assumes a Shimano compatible cassette in both cases. It was kind of designed this way to provide a certain path of usability for older system parts.
1. do u mean that DA7700 shifter is not compatible with DA7402 rear derailleur?
BUT
2. DA7700 cassette+hub is compatible with DA7402 rear derailleur?
I am kinda confused here... 😂
11-05-20, 08:36 AM
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I’ve done some Dura Ace alternate cable routing but not what you are saying.
Old 74XX DA RD had a ratio of 1.9 compared to Shimano’s 1.7.
There is no unique Shimano cassette spacing for DA. 8 speed is 4.8, 9 speed is 4.35. You could use Sunrace for that matter.
You just need to move the derailleur over 4.35mm, or pretty close.
My understanding is 10 speed Shimano road shifters pull 2.3mm of cable. So 2.3mm x 1.9 (DA 74XX) = 4.37mm.
So 10 speed shifters should shift an RD-DA 7402 with a 9 speed cassette.
John
Old 74XX DA RD had a ratio of 1.9 compared to Shimano’s 1.7.
There is no unique Shimano cassette spacing for DA. 8 speed is 4.8, 9 speed is 4.35. You could use Sunrace for that matter.
You just need to move the derailleur over 4.35mm, or pretty close.
My understanding is 10 speed Shimano road shifters pull 2.3mm of cable. So 2.3mm x 1.9 (DA 74XX) = 4.37mm.
So 10 speed shifters should shift an RD-DA 7402 with a 9 speed cassette.
John
11-05-20, 09:18 AM
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I’ve done some Dura Ace alternate cable routing but not what you are saying.
Old 74XX DA RD had a ratio of 1.9 compared to Shimano’s 1.7.
There is no unique Shimano cassette spacing for DA. 8 speed is 4.8, 9 speed is 4.35. You could use Sunrace for that matter.
You just need to move the derailleur over 4.35mm, or pretty close.
My understanding is 10 speed Shimano road shifters pull 2.3mm of cable. So 2.3mm x 1.9 (DA 74XX) = 4.37mm.
So 10 speed shifters should shift an RD-DA 7402 with a 9 speed cassette.
John
Old 74XX DA RD had a ratio of 1.9 compared to Shimano’s 1.7.
There is no unique Shimano cassette spacing for DA. 8 speed is 4.8, 9 speed is 4.35. You could use Sunrace for that matter.
You just need to move the derailleur over 4.35mm, or pretty close.
My understanding is 10 speed Shimano road shifters pull 2.3mm of cable. So 2.3mm x 1.9 (DA 74XX) = 4.37mm.
So 10 speed shifters should shift an RD-DA 7402 with a 9 speed cassette.
John
Anyway, at the moment my DA7700s are on my shifter (9-speed) + cassette (9-speed) + hub. DA7402 rear derailleur should b compatible with difference of 0.02mm... I hope... 😂😂😂
Time to shop for a DA rd-7402.
Anyone wanna sell?
11-05-20, 09:56 AM
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Your 7700 9 speed shifters won’t work. You need to use 10 speed shifters.
Your quest for a specific look is folly if you already have a 7700 rear derailleur. No one removes a better component for a worse one.
The Dura Ace work arounds are intended for those who have the effected components, generally due to 7 speed width limitations, and be able to make them work.
John
Your quest for a specific look is folly if you already have a 7700 rear derailleur. No one removes a better component for a worse one.
The Dura Ace work arounds are intended for those who have the effected components, generally due to 7 speed width limitations, and be able to make them work.
John
Likes For 70sSanO:
11-05-20, 11:01 AM
#9
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If I understand u correctly:
1. do u mean that DA7700 shifter is not compatible with DA7402 rear derailleur?
It is not compatible for 9 sp. As mentioned above by many, the movement of the combo will be proper for a 8 sp cassette. Because of the higher actuation ratio, the 74xx RD will move more per shift than the 7700 RD.
BUT
2. DA7700 cassette+hub is compatible with DA7402 rear derailleur?
When combined with a 10 sp Shimano road shifter, (non ST*4700 Tiagra, which has a different pull). The 10 sp shifter's lower pull amount & the higher actuation ratio of the RD-74xx will result in the proper RD movement for 9 sp.
I am kinda confused here... 😂
1. do u mean that DA7700 shifter is not compatible with DA7402 rear derailleur?
It is not compatible for 9 sp. As mentioned above by many, the movement of the combo will be proper for a 8 sp cassette. Because of the higher actuation ratio, the 74xx RD will move more per shift than the 7700 RD.
BUT
2. DA7700 cassette+hub is compatible with DA7402 rear derailleur?
When combined with a 10 sp Shimano road shifter, (non ST*4700 Tiagra, which has a different pull). The 10 sp shifter's lower pull amount & the higher actuation ratio of the RD-74xx will result in the proper RD movement for 9 sp.
I am kinda confused here... 😂
11-05-20, 12:12 PM
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