[jmtbkr]

I'm recently having problems getting the chain to drop into the granny gear. The der. pops when I shift but sometimes the chain does not drop off the middle gear. I'm downshifting NOT under pressure, like I stop pedaling for a turn and then usually ease into the pedals after the shift, but lately, no go. On the stand it works every time, but on the trail, its getting to be a real pain getting off the bike and going back down the trail for every climb.
Drivetrain:
RF cranks and rings (just replaced middle ring), 20t granny
XTR top pull der.
IG 90 chain - fairly new and always clean

downshifts from big to middle ring are perfect, and all the upshifts are perfect.
I've got the low stop set all the way to the inside, like almost no slack in the cable. Der is set straight and height is perfect.

anyone???

 

[FrankinMich]

I had the same problem....

Sounds like you are familiar with setting up your front derailleur, but it never hurts to go over the steps carefully. One of the best descriptions of how to set your derailleurs can be found here: http://www.utahmountainbiking.com/fix/index.htm Scroll down the "Fix-It Selections" box on the left and click on the "Derailleur, Front Tune" link. Use the instructions to double check yourself.

Note that the first thing they tell you to do in the tune up section is loosen the cable. I forgot to do this and it drove me nuts trying to adjust the low gear limit screw. Another trick they mention is toeing in the cage. This seemed to help my middle-to-granny shift as well. Just don't over do the toe in adjustment -- a slight bend is all you need.

If you do not want to bend the derailleur cage, you can try rotating the entire derailleur so that the rear of the cage is slightly closer to the bike frame than the front of the cage. Here again, just a very slight adjustment is all you need.

Hope this helps! :thumbsup:

 

[rockyuphill]

The derailleur cage literally derails the chain by pushing on it sideways, so as the chain gets more worn and more flexible sideways, it deflects more without carrying that deflection along the chain to derail it off the middle ring. If you changed your chain you may find that it worked as good as new (note to self, dig out chain wear indicator and check my chains for wear - it's about that time).

Do you find that it shifts into the granny more easily if it's in the biggest two cogs at the back, as the chainline is already pulling it that way?

If this happens to be a square taper Race Face 5 bolt compact crank, there's a chance that the reinstallation of the cranks after the middle ring change might have just moved the chainline inward by a bit.

 

[jmtbkr]

If this happens to be a square taper Race Face 5 bolt compact crank, there's a chance that the reinstallation of the cranks after the middle ring change might have just moved the chainline inward by a bit.

exactly what I believed happened. So I wound up movong the BB half turn towards the drive side (moving chain line). Ove rhte years, the taper, either on the crank or BB 'wears' down a little, changing the chain line.

 

[MillerSHO]

Couldn't you just re-do your high/low limits to take the new chainline into consideration?

 

[Becane73]

I have the exact same problem ever since I moved to a FS bike from my hardtail Based on what RockUpHill said, I'm going to double checky my crank setup.

I might have my crank either too far out or too far in (I'm thinking it's probably out too far since I added a spacer to my e-type derailleur setup) I used to use a typical clamp on front derailleur but ever since I moved to the e-type I've had trouble figuring out the right spacing.

Anyone have any idea how many if spacers I should use on an XT M760 crank, e-type front derailleur on a 2005 Stumpjumper FSR? I think I'll ask this question in the Specialized forum too.

Thanks everyone.

 

[rockyuphill]

exactly what I believed happened. So I wound up movong the BB half turn towards the drive side (moving chain line). Ove rhte years, the taper, either on the crank or BB 'wears' down a little, changing the chain line.

My first set of RF Turbines had to be replaced because the square taper hole eventually stretched to the point where the end of the spindle was flush with the fixing bolt head surface on the crank, the bolt wouldn't compress anything. The chainline moved so it was well inside of the minimum chainline setting on that old XT derailleur. That's when I discovered that overtightening your crank fixing bolt on square taper cranks as a method of preventing the crank from coming loose can have negative consequences. :madman: And then I switched to ISIS.