Author Topic: Shimano 9speed STI problems  (Read 1842 times)

Dave_C

  • Trying to get rid of my belly... and failing!
Shimano 9speed STI problems
« on: June 05, 2016, 07:02:26 pm »
I've got an aging set of 9 Speed shimano 4403?? Shimano Tiagra triple on my Dawes Tourer. The STIs have taken the odd nose bash for time to time as I've has a few spills with my thrills. But they have always worked faultlessly.

I've just changed my Tiagra front mech for an Utegra 9/10 speed mech as the cable has always got in the way of the mech moving into the smallest ring.
Now in setting it up the cable was put under a little high tension but released while I adjusted the alignment of the mech to line up with the chain rings. The problems started here. The release leaver started to not release the cable and once the mech was lined up it has continued to not release the cable. Cable was removed and threaded back to ensure no entrapment. Not 1/10 times it will release to the lower cog from top in one go. I know I could aid release by partially pushing on the brake to release strain on the cable mechanism in the STI but even this is very miss over hit.

Has something broken in the STI and if so can it be fixed or it is gubbed?

If the answer to the 'is it broken' question, is Yes, please look for my 'Wanted' post for a triple STI lever question with will come up soon.

Cheers.

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@DaveCrampton < wot a twit.
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Dave_C

  • Trying to get rid of my belly... and failing!
Re: Shimano 9speed STI problems
« Reply #1 on: June 06, 2016, 07:05:14 am »
Oh, can I use a 10 speed triple with 9 speed. I guess the pull distance is the same?

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Feanor

  • It's mostly downhill from here.
Re: Shimano 9speed STI problems
« Reply #2 on: June 06, 2016, 10:26:01 pm »
Yes, 9 and 10 spd front mechs have the same pull ratio I think.
I've certainly not had a problem mixing them.

Sounds like something's wrong with the cable tension at the front.
The spring in the front mech is very strong, and you need to clamp the cable up well.
It's possible the cable is no longer seated correctly inside the shifter.
I'd be inclined to set it up again from scratch.
Here's how I do it...

Un-clamp the cable from the mech.
It should fall back to the granny ring.
Adjust the limit screw if necessary to allow it to properly sit over the granny ring.

Ensure the shifter has let out all the cable it can, by operating the inner paddle whilst pulling on the cable at the down-tube.
Sometimes, the nipple at the end of the cable has not seated correctly in the rotating drum inside the shifter.
Inspect it, and whilst maintaining firm hand-tension on the cable, check the shifter can operate up and down.
Be sure to leave it with the most slack cable paid out.

There is a small plastic wedge that comes with the mech, which holds it in a partially-activated position ( ie not fully relaxed onto the granny ).
With this wedge in place, pull the cable firmly by hand into the clamp on the mech, and nip up the clamp bolt.
Operate the shifter to pull it into the middle-ring position.
The plastic wedge is released, can now be removed.
Shifting back down to the granny will now fall back *beyond* the position it was wedged in, as the powerfull spring takes up tension in the cable.
It should now sit correctly on the granny ring.

That's really all it should take.

Cudzoziemiec

  • Solar powered, tea fuelled cycle-wol
Re: Shimano 9speed STI problems
« Reply #3 on: June 09, 2016, 03:14:38 pm »
The only exception (so far at least) to the common 9 and 10 speed pull ration is Tiagra 4700, which is 10-speed but uses the 11-speed pull ratio, making it incompatible with any other groupset.
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