Bicycle Mechanics - 8 spd bar end / 7400 Dura ace derailleur

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bikex10
05-20-07, 06:49 AM
I currently have a bike that I have built with 8spd bar ends on it. I have 7400 cranks on it and would like to put a 7400 series rear derailleur on it. I am currently running a ultegra rear derailleur.
Is the compatibility issue with the rear shifter/derailleur in the ratio of the dura ace derailleur. The shifter says it cannot be used with a dura ace rear derailleur.
I have setup some other components that were an odd mix and it was a matter of a little more finicky adjustment.
Can I make this combo work?
Thanks


vpiuva
05-20-07, 07:56 AM
Friction mode only. It will never index no matter how much you play with it. But it will work friction, and it's a nice RD

Ziemas
05-20-07, 08:00 AM
Friction mode only. It will never index no matter how much you play with it. But it will work friction, and it's a nice RD
Actually the wrench at my LBS made this combo work for me. I have no idea how he did it, and I know it's not supposed to work, but it did work.


vpiuva
05-20-07, 08:12 AM
Actually the wrench at my LBS made this combo work for me. I have no idea how he did it, and I know it's not supposed to work, but it did work.

Interesting. According to Sheldon's chart, this RD will index in 8 speed mode using a 9 speed shifter. Any chance your LBS is used a 9s shifter?

Ziemas
05-20-07, 08:47 AM
Interesting. According to Sheldon's chart, this RD will index in 8 speed mode using a 9 speed shifter. Any chance your LBS is used a 9s shifter?
Actually it was a 7 speed shifter.

EDIT: My bad, I just pulled them out of a box. They are 8 speed SL-BS64 shifters.

well biked
05-20-07, 09:21 PM
I currently have a bike that I have built with 8spd bar ends on it. I have 7400 cranks on it and would like to put a 7400 series rear derailleur on it. I am currently running a ultegra rear derailleur.
Is the compatibility issue with the rear shifter/derailleur in the ratio of the dura ace derailleur. The shifter says it cannot be used with a dura ace rear derailleur.
I have setup some other components that were an odd mix and it was a matter of a little more finicky adjustment.
Can I make this combo work?
Thanks

What model bar-end shifters are they? Ultegra? It's funny, because the questions that usually arise from indexed Shimano bar end shifters are the other way around: will the Dura-Ace indexed bar-ends work with rear derailleurs other than Dura-Ace? What makes that question somewhat confusing is that nine speed and ten speed Dura-Ace bar-end shifters come with instructions stating that the shifters will only work with Dura-Ace RD's. And this isn't true, it's only eight speed and earlier Dura-Ace that matters in this regard (rear indexing)-

reve_etrange
05-21-07, 01:21 AM
All Shimano derailleurs are compatible with all Shimano index systems.
The exception is the pre-1996 Dura-Ace RD, which only does 6, 7 and 8-speed indexing.

Index shifting is built into the shifters (which are made to move between detentes corresponding to exact cable amounts). The RD's only differ in the amount of mechanical advantage they provide to the cable (the actuation ratio).


Shimano's claims about product compatibility are a pack of lies. Except for the Flight Deck computer mounts.

cs1
05-21-07, 02:12 AM
I currently have a bike that I have built with 8spd bar ends on it. I have 7400 cranks on it and would like to put a 7400 series rear derailleur on it. I am currently running a ultegra rear derailleur.
Is the compatibility issue with the rear shifter/derailleur in the ratio of the dura ace derailleur. The shifter says it cannot be used with a dura ace rear derailleur.
I have setup some other components that were an odd mix and it was a matter of a little more finicky adjustment.
Can I make this combo work?
Thanks

Lonnie:

From what I can see, you have an Ultegra derailleur on that works. Why do you want to put on a DA that doesn't? I'm a bit confused.

Tim

bikex10
05-21-07, 06:06 AM
From what I can see, you have an Ultegra derailleur on that works. Why do you want to put on a DA that doesn't? I'm a bit confused.Tim:
I am in the processof a build for my wife. I would like to take the Ultegra derailleur and put it on her build and get a Dura Ace of the same series as my cranks that I have on my training bike.

reve_etrange
05-22-07, 02:17 AM
As per my above post, your Dura-Ace 7400 RD will work fine with 8-speed.
It is well known that Shimano lies about product compatibility.

cs1
05-22-07, 03:01 AM
Tim:
I am in the processof a build for my wife. I would like to take the Ultegra derailleur and put it on her build and get a Dura Ace of the same series as my cranks that I have on my training bike.

Well, that answers that question. Good luck

Tim

smiller
11-04-08, 02:58 PM
I've done this and i'll dissagree with reve above. the ult 8sp shifters might shift the 7400 in friction, but it won't index well since the shift ratios are different. about the same difference as new shimano and campy. 9sp ultegra shifters will shift 8sp with the 7400, but if you want the 8sp ult shifters to shift the entire range well, you'll need a shiftmate.
they work great but they are a bit pricey at $35