My DA 7700 only goes to 8!

[torquer]

Over the winter, I noticed that one of my bikes was skipping the 8th cog when I shifted down from the inner-most cog, and landing on the 7th position. I could shift back up to either position, but not back down from 9 to 8. This occured with various cassettes and wheels.

When a new chain and cassette didn't improve things, I brought it to the local shop, where they tried adjusting the derailer, then replaced the cable, but couldn't fix it either.

In fact, they discovered that the shifter was moving the derailer across the entire width of the cassette in seven clicks (i.e. functioning like an eight-speed), which meant it always would skip a cog in either direction. Typically, this was the eighth position when moving inboard, and the 2nd position moving outboard.

The 7700 shifter was purchesed new around 2003 or 04, so figure 10-15K miles; rear derailer may be a 7800 (7700 was being phased out about that time). Any educated guesses about what is happening here?

I know DA isn't easily rebuildable, so do I have any options other than replacement? Could there be some obscure cable-routing glitch that could account for this problem (or conversely, an alternate routing that could fix it?) J-TEK to the rescue? Or do I sit tight and wait for Ultegra DI2?

Any thought would be welcome.

Edit: here's an article I came across showing how the 7700 shifter mechanism operates, and what sometimes goes wrong.
http://norvil.net/pedal/service/shimanosti/duraace9sti/detail.php
Nice photos, but I still don't have the aptitude (not to mention time, tools and space) to launch into something like this: "Failing that, build the plate up by welding and then file/grind back to shape. But find a good weldor."

[EricEstlund]

Do you know your rear drl. hanger to be aligned?

[firerescuefin]

Over the winter, I noticed that one of my bikes was skipping the 8th cog when I shifted down from the inner-most cog, and landing on the 7th position. I could shift back up to either position, but not back down from 9 to 8. This occured with various cassettes and wheels.

When a new chain and cassette didn't improve things, I brought it to the local shop, where they tried adjusting the derailer, then replaced the cable, but couldn't fix it either.

In fact, they discovered that the shifter was moving the derailer across the entire width of the cassette in seven clicks (i.e. functioning like an eight-speed), which meant it always would skip a cog in either direction. Typically, this was the eighth position when moving inboard, and the 2nd position moving outboard.

The 7700 shifter was purchesed new around 2003 or 04, so figure 10-15K miles; rear derailer may be a 7800 (7700 was being phased out about that time). Any educated guesses about what is happening here?

I know DA isn't easily rebuildable, so do I have any options other than replacement? Could there be some obscure cable-routing glitch that could account for this problem (or conversely, an alternate routing that could fix it?) J-TEK to the rescue? Or do I sit tight and wait for Ultegra DI2?

Any thought would be welcome.


This isn't a shot a Shimano, but after going through 2 rear shifter/levers (Dura Ace -1 was warrantied), I changed groupo Manuf. Good chance that you need to replace that shifter/lever. FWIW I had Old Potato rebuild my Record 10 after about 25K and it works as good as new.

[eddief]

but i was just diddling at length when i could not get the the shifter to stop the chain on the next to smallest cog on the way down the cassette from the biggest cog. it would somehow skip from 3rd from the bottom to 1st and would not stop at number 2.

going up was just fine for all 9 cogs.

not sure which thing i did fixed it, but here are the steps i took.

1. bought a new cassette which i did not need because i fixed the prob before the cassette arrived in the mail.

2. replaced the shifter cable. i think the one i replaced had a slightly larger head end than the one i installed for the fix.

3. greased the cable...which i almost never do.

4. trimmed shorter the housing near the derailleur????

5. made sure the cable was running smoothly through all housing and ferrules.

all shifting to all cogs now works perfectly.

unfortunately not sure which action did the trick.

i am inclined to believe the cable was not seated just right in the shifter body.

[vsefiream]

Just my .02 but IIRC the STI levers are prone to getting stickey due to solidification of the grease Shimano used to lubricate the mechanism. My last set would not shift down at all. As some suggested here, I removed the shifter, hosed it out with WD40 to clean out the old grease. I blew it out and lubed with super-lube. They worked great after that. I think you might be experiencing the same issue starting to set in.

[Germany_chris]

but i was just diddling at length when i could not get the the shifter to stop the chain on the next to smallest cog on the way down the cassette from the biggest cog. it would somehow skip from 3rd from the bottom to 1st and would not stop at number 2.

going up was just fine for all 9 cogs.

not sure which thing i did fixed it, but here are the steps i took.

1. bought a new cassette which i did not need because i fixed the prob before the cassette arrived in the mail.

2. replaced the shifter cable. i think the one i replaced had a slightly larger head end than the one i installed for the fix.

3. greased the cable...which i almost never do.

4. trimmed shorter the housing near the derailleur????

5. made sure the cable was running smoothly through all housing and ferrules.

all shifting to all cogs now works perfectly.

unfortunately not sure which action did the trick.

i am inclined to believe the cable was not seated just right in the shifter body.

I would bet money on that one..

Remember the casing needs to be long enough for the cable to enter the derailleur straight but not with so big of a loop that that casing get flexy. The smallest loop that puts the cable in straight.

Chris

[RPS]

In fact, they discovered that the shifter was moving the derailer across the entire width of the cassette in seven clicks (i.e. functioning like an eight-speed), which meant it always would skip a cog in either direction.

Could there be some obscure cable-routing glitch that could account for this problem (or conversely, an alternate routing that could fix it?)

Any thought would be welcome.
Had same problem with a friend’s bike a couple of years ago and it was due to cable routing. You can read about it here:

http://forums.thepaceline.net/showthread.php?t=58322&page=1&pp=15

Take a look at the Sheldon Brown page which shows how attaching the cable to the derailleur differently can make 7 clicks (8-speed) move through the entire range of small to large on a 9 speed. That was the problem with my friend's bike and I just didn't notice it.

I’m guessing that since you had a bike shop do the work they would have installed it right, but it’s worth a quick look anyway in my opinion.

[TAW]

Had same problem with a friend’s bike a couple of years ago and it was due to cable routing. You can read about it here:

http://forums.thepaceline.net/showthread.php?t=58322&page=1&pp=15

Take a look at the Sheldon Brown page which shows how attaching the cable to the derailleur differently can make 7 clicks (8-speed) move through the entire range of small to large on a 9 speed. That was the problem with my friend's bike and I just didn't notice it.

I’m guessing that since you had a bike shop do the work they would have installed it right, but it’s worth a quick look anyway in my opinion.

We see this occasionally at the shop. If you have problems going up and down, this is usually it.

[oldpotatoe]

Had same problem with a friend’s bike a couple of years ago and it was due to cable routing. You can read about it here:

http://forums.thepaceline.net/showthread.php?t=58322&page=1&pp=15

Take a look at the Sheldon Brown page which shows how attaching the cable to the derailleur differently can make 7 clicks (8-speed) move through the entire range of small to large on a 9 speed. That was the problem with my friend's bike and I just didn't notice it.

I’m guessing that since you had a bike shop do the work they would have installed it right, but it’s worth a quick look anyway in my opinion.

But this doesn't eliminate one of the 'clicks' in the lever, just changes how far the rear der. moves each click. I'm guessing it was gunked up, we see this all the time. A shot of the 'STI rebuild kit', WD-40 then spray lube, often fixes it.

[TAW]

In fact, they discovered that the shifter was moving the derailer across the entire width of the cassette in seven clicks (i.e. functioning like an eight-speed), which meant it always would skip a cog in either direction. Typically, this was the eighth position when moving inboard, and the 2nd position moving outboard.



Skipping a gear in both directions indicates that the rear der is not moving as it should, which almost always indicates a problem with the cable attachment to the rear der.

[torquer]

Thanks for all the possibilities. Here's my update:
1. Derailer hanger aligned: check.
2. Cable attachment: same path as my other 7700, which works fine.
3. WD-40/spray lube: did it, no change.

What I saw when I took the wheel off was that the first "click" from the inside position outward moved the der. much more than each subsequent shift. This suggests that the problem is in the shifter mechanism. I'll try another round of WD-40 and lube, but I suspect that I'll be searching the 'bay for an NOS right shifter (unless the classifieds here turn up anything.)

[thwart]

Ah... please note that post above where the ailing Campy Record ergo was rebuilt to be like new (typically for less than $100) after 25K of use.

I do hear the spinning reels last forever. :D

[rustychisel]

left field idea: the cable outer mounting point (often underside of the chainstay) is susceptible to being nudged by the heel of your shoe, pushing the ferrule slightly out of the eyelet. It sits 'up' on the shoulder of the mount. If everything is perfectly setup/aligned but this happens, the end result is exactly as you describe. 8/9 gears or 9/10

[torquer]

Ah... please note that post above where the ailing Campy Record ergo was rebuilt to be like new (typically for less than $100) after 25K of use.

I do hear the spinning reels last forever. :D
Thanks for the info.
With the $200 I would save (Campy rebuild vs. NOS 7700s) I could buy one third of a Record cassette. ;)
http://forums.thepaceline.net/showthread.php?t=92579

[RPS]

But this doesn't eliminate one of the 'clicks' in the lever, just changes how far the rear der. moves each click. I'm guessing it was gunked up, we see this all the time. A shot of the 'STI rebuild kit', WD-40 then spray lube, often fixes it.
Correct, it doesn't eliminate it, it just makes the eight click unnecessary.

When cable is routed incorrectly, seven clicks (like on 8-speed) will move the derailleur from one end to the other. If you adjusted the RD limits further I'm sure you could get the 8th click but then the chain would be off the cassette.

For what it's worth, when it happened to me on friend's bike it was brand new shifters. No gunking at all.