Rear derailleur initial cable tension

Good morning, all -

When installing a new rear derailleur, how tightly should the cable be
pulled, prior to any STI adjustments? I just installed a rear
derailleur, and I set the shifter to the highest gear (smallest cog),
and then pulled the cable snug, but not tight. I'm having trouble
getting the indexing to work smoothly and accurately in both
directions, and I suspect the cable tension is wrong, but no amount of
tweaking (with the barrel adjuster) seems to fix it. Its a 105 9-speed
derailleur, and a Dura-Ace 9-speed STI shifter.

Any advice would be appreciated.

Josh

Josh Hassol wrote:
Good morning, all -

When installing a new rear derailleur, how tightly should the cable be
pulled, prior to any STI adjustments? I just installed a rear
derailleur, and I set the shifter to the highest gear (smallest cog),
and then pulled the cable snug, but not tight. I'm having trouble
getting the indexing to work smoothly and accurately in both
directions, and I suspect the cable tension is wrong, but no amount of
tweaking (with the barrel adjuster) seems to fix it. Its a 105 9-speed
derailleur, and a Dura-Ace 9-speed STI shifter.

Any advice would be appreciated.

Josh

make sure the pulley is aligned with the smallest cog first. Pull the
cable tight. Shift once and ensure the pulley is aligned with the next
cog bigger, adjust with barrel adjust, shift again and check each
time....at the biggest, ensure the limit screw will not allow the chain
to go into the spokes.

Josh Hassol wrote:
Good morning, all -

When installing a new rear derailleur, how tightly should the cable be
pulled, prior to any STI adjustments? I just installed a rear
derailleur, and I set the shifter to the highest gear (smallest cog),
and then pulled the cable snug, but not tight. I'm having trouble
getting the indexing to work smoothly and accurately in both
directions, and I suspect the cable tension is wrong, but no amount of
tweaking (with the barrel adjuster) seems to fix it. Its a 105 9-speed
derailleur, and a Dura-Ace 9-speed STI shifter.

Any advice would be appreciated.

Josh

I also use new inner wire and housing with a new rear der and make sure
the under BB guide is clean.

Qui si parla Campagnolo wrote:

make sure the pulley is aligned with the smallest cog first. Pull the
cable tight. Shift once and ensure the pulley is aligned with the next
cog bigger, adjust with barrel adjust, shift again and check each
time....at the biggest, ensure the limit screw will not allow the chain
to go into the spokes.

Thanks. How is the initial alignment with the smallest cog achieved,
prior to pulling the cable tight?

Qui si parla Campagnolo wrote:

I also use new inner wire and housing with a new rear der and make sure
the under BB guide is clean.

Yup! Did that. Thanks.

"Josh Hassol" wrote in message
ups.com...
Good morning, all -

When installing a new rear derailleur, how tightly should the cable be
pulled, prior to any STI adjustments? I just installed a rear
derailleur, and I set the shifter to the highest gear (smallest cog),
and then pulled the cable snug, but not tight. I'm having trouble
getting the indexing to work smoothly and accurately in both
directions, and I suspect the cable tension is wrong, but no amount of
tweaking (with the barrel adjuster) seems to fix it. Its a 105 9-speed
derailleur, and a Dura-Ace 9-speed STI shifter.

Any advice would be appreciated.


Bolt on the new rear derailleur (check derailleur hanger),
Shift to highest gear (smallest cog),
Adjust (high) limit screw so that the upper pulley is straight under the
smallest cog,
Screw the barrel adjuster or adjustscrew at the back of the derailleur
almost in,
Install (new) inner wire and pull it tight and tighten the bolt,
Unscrew (high) limit screw a little, you will see that the upper pulley will
move a little outward,
Adjust with the barrel adjuster or adjust screw (preferred) at the back of
derailleur so that the upper pulley is straight under the smallest cog
again,
Put on the chain and shift up and down. Only a little tweaking will be
necesarry if the derailleur hanger is straight, the inner wire moves
smoothly and the upper pulley doesn't have to much play.


Lou

Lou

On 31 Jan 2006 06:13:24 -0800, "Josh Hassol" wrote:

Good morning, all -

When installing a new rear derailleur, how tightly should the cable be
pulled, prior to any STI adjustments? I just installed a rear
derailleur, and I set the shifter to the highest gear (smallest cog),
and then pulled the cable snug, but not tight. I'm having trouble
getting the indexing to work smoothly and accurately in both
directions, and I suspect the cable tension is wrong, but no amount of
tweaking (with the barrel adjuster) seems to fix it. Its a 105 9-speed
derailleur, and a Dura-Ace 9-speed STI shifter.

Any advice would be appreciated.

IMO, the cable is probably dragging just a bit. I'd replace it and
try again. Use *really good* cables on 9s setups; motion transmission
accuracy is important with these.
--
Typoes are a feature, not a bug.
Some gardening required to reply via email.
Words processed in a facility that contains nuts.

On 31 Jan 2006 06:13:24 -0800, "Josh Hassol" wrote:

I'm having trouble
getting the indexing to work smoothly and accurately in both
directions, and I suspect the cable tension is wrong, but no amount of
tweaking (with the barrel adjuster) seems to fix it. Its a 105 9-speed
derailleur, and a Dura-Ace 9-speed STI shifter.

Perhaps the routing of the cable at the attachment bolt is incorrect.
It goes under the bolt and not above or through the clamp.

Josh Hassol wrote:
Good morning, all -

When installing a new rear derailleur, how tightly should the cable be
pulled, prior to any STI adjustments? I just installed a rear
derailleur, and I set the shifter to the highest gear (smallest cog),
and then pulled the cable snug, but not tight. I'm having trouble
getting the indexing to work smoothly and accurately in both
directions, and I suspect the cable tension is wrong, but no amount of
tweaking (with the barrel adjuster) seems to fix it. Its a 105
9-speed derailleur, and a Dura-Ace 9-speed STI shifter.

Any advice would be appreciated.

Josh

I find that the smallest cog tends to cause the cable to have very little
tension.
--
Phil, Squid-in-Training

Josh Hassol wrote:
Qui si parla Campagnolo wrote:

make sure the pulley is aligned with the smallest cog first. Pull the
cable tight. Shift once and ensure the pulley is aligned with the next
cog bigger, adjust with barrel adjust, shift again and check each
time....at the biggest, ensure the limit screw will not allow the chain
to go into the spokes.

Thanks. How is the initial alignment with the smallest cog achieved,
prior to pulling the cable tight?

By eyeball and moving the der right or left with the limit screw. You
can also slowly rotate the crank and hear if the chain is 'tickling'
the next cog bigger, than move it an RCH the other direction.