Zaphod Beeblebrox 

I'm having an issue with my Gran Course getting into high gear. I've got it outfitted with a Dura Ace 7700 drivetrain. Got the High limit screwed all the way out and when shifting it on the stand or on the road I can't get the chain onto the small sprocket. It shifts the other 8 perfectly…what's the deal? I've got 9 speed everything…I'm sorta surprised its not working.

I've checked the derailleur hanger and it doesn't look bent. Do I just need to throw a spacer on the drive side?

due ruote 

Can you move the derailleur by hand to make it shift? If not the RD is at its limit and I'd suspect maybe a slightly bent hanger.

dddd

Often I work on index-shifting bikes where the cable adjustment is fully one gear too tight, so even though the derailer shifts snappily to a smaller cog, it won't shift to the smallest cog.

OldsCOOL

Also good to take a visual of the limiter pad to see if the screw is touching even at max limit. In this case it's time to respace but the question as to "why" remains.

iab

No worries. I can't hit the high gear either. But that is because I am old and fat.

rhm

If the derailleur adjustment screw is all the way out, and the cable is all the way slack, then yeah, a spacer sounds like a good idea to me. A thin axle spacer under the lock nut should do it. Or possibly between the derailleur and the hanger.

Zaphod Beeblebrox 

Well to be fair i can only push the high gear down hills. My girlfriend is fast though so i gotta try and catch her when i can ;-)

ill try a spacer between the derailleur and the hanger. Its the easiest thing it seems, and i won't feel a need to redish the rear wheel.
This setup is basically experimental. If i get it dialed in well enough it will get cold set and the frame aligned over the winter. And maybe paint ....

CroMo Mike 

I'm having the same problem. Even when using a narrow-6 freewheel on a regular-6 hub (so there is extra space between the smalll cog and the dropout), it does not like to drop onto the last cog unless I adjust the derailleur to go too far to the right - in which case it sometimes drops the chain into the space between the small cog and the dropout. I'm running Campy Nuovo Record, Super Record, and C-Record RD's on Sun Tour Winner Pro FW's and modern Shimano 6-7-8 chains like the IG-70. I've concluded that the problem is that the Shimano chain is flexible enough that it is happy to run at an angle that would cause older chains to hop over to the next cog. The Shimano chain works so well otherwise that i have been putting up with the last-cog problem. It will shift over to the small cog if I shift from the center of the cluster, hopping 3 or 4 cogs at a time.

crank_addict

That would annoy me. Without the chain on, should see a full range by a mock shift. Much has already been mentioned but the chain could be the quirk. Is it Shimano or compatible to the DA drivetrain? Bushingless chain allows more twist vs. bushing. Did you change out the bottom bracket spindle? Proper chain line?

Zaphod Beeblebrox 

The BB spindle is potentially a shade shorter than would be optimal. And yes, the chain is a shimano chain that is compatible.

I double checked the limit screw, its all the way out and when i shift to the Highest position the cable goes slack.

Miele Man

Is there any crud inside the derailler? Maybe a bit of grit? Does the derailler move freely? Are you sure you haven't mistakenly adjusted the low gear screw?

Cheers from Miele Man

gaucho777 

+1. I found myself in a similar situation when I switched from a 6-speed to 7-speed freewheel on my Look. Derailleur hanger was fine and the limit screw opened up, but the chain just wouldn't quite drop all the way down to the smallest cog all the time. A thin 1-2mm spacer is all you will likely need. Problem completely went away in my case. Adding a spacer & redishing the wheel this small amount seems to me a better option than adding a spacer behind the RD since the latter may increase the chance of damaging the derailleur hanger threads by not having a fully engaged RD.

John E

The only problem with the spacer is that it will make your chainline worse in some gears (and better in others). Still, it is admittedly your best option if the derailleur cage simply cannot move any farther outboard.

gaucho777 

^Agreed, though I would venture that if the RD doesn't reach the high gear, the chainline may not be optimal as is and a spacer may actually improve the chainline.

squirtdad

I resemble that remark

jiangshi

Not enough info, but it sounds like chain line to me. I would bet that the wrong BB is being used, and that the frame may be out of alignment as well.

Crank and BB? That would actually start to give a data point. It shouldn't be 20 questions for a long time member. Tell us the set up, in detail, and go from there.

Bandera

Furrowing your brow while looking at your derailleur hanger's alignment with a table leg does not substitute for checking it's actual alignment with the proper tool.
Failing that all else is idle conjecture.
1st things 1st, get that done properly and proceed from there.

-Bandera

Chrome Molly

What he just said... Check the hanger alignment first. Visual is pretty difficult to do given the hanger is relatively small and even the RD hanging off it isn't always a visual alignment if the hanger is bent both vertically and horizontally.

Zaphod Beeblebrox 

I'm 99% sure this is gonna come down to chain line. The crankset is a TA set up as a triple. I'm still using the Dura Ace BB that it came to me with which i believe was a 7400 double.

IIRC the correct BB length for a TA Triple is super long like 125 or so, which means I'm probably way off.... But hey the inner ring doesn't hit the frame so its not the end of the world.

As i may have mentioned this bike will get torn down at the end of the season and get aligned by someone with the right tools and know how. So if the hanger is tweaked or whatever that will get fixed at that time

Thanks folks

Bandera

Good plan.

-Bandera

IthaDan 

I've run into this with a too long chain that lets the parallelogram of the RD hit the chainstay or housing, keeping it from fully retracting.

MetinUz

I doubt this has anything to do with the chainline, at least not when there is a problem when at the outer chainring. Is the rear shift cable slack when you shift to the smallest cog?

dddd

+1 ...The chainline affects how the chain feeds onto the lower pulley, but won't affect how the chain feeds out of the top pulley onto the cogs.

IthaDan also made good points as to possibly why the derailer won't retract fully to the last cog position.

Possibly also there is a problem with the cable sliding freely in the rear cable housing. The derailer must snap smartly to the last-cog position in response to the shifter's command, but won't if the return spring isn't providing enough tension or if the cabling action isn't smooth.

crank_addict

'band-aid' test / cheat fix-

(Assuming the OP checked all the above suggestions)

Remove rear wheel, skewer. Place spacer washer on each end of axle. Re-assemble. Most likely will be tight fitting into the dropout, so slightly and temporarily spread it to install the wheel assembly (not permanent or cold set). With the derailleur limiter screws backed out, should easily allow the chain to drop into the small cog.

jeirvine 

Is the RD return spring strong? I've had that problem with used/worn units. Is the cable housing section too short/stiff?