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Old 02-23-10, 08:59 AM   #1
Brando_T.
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Fine tuning a Sora triple front derailleur

I'm in the end stages of converting my Specialized Sirrus from flat bar to drop bar. I have a set of used Sora brifters and a used Sora triple derailleur installed, and i'm trying to complete the tuning of it. The bike has the Sugino crank that shipped with it.

I've looked at Park Tools and other sites to get the info on the setting the limit screws & derailleur positioning. At this point, I can successfully:

Shift from small to middle
shift from middle to big
Shift from middle to small

However, I cannot get the derailleur to shift down from big to middle. Related to this (I think) is that I seem to keep the cage from rubbing the chain while on the middle chainring.

I suspect this is related to cable tension. However, it appears that I don't have the ability to fine adjust tension on the front derailleur now - the adjustment was at the shifter on the flat bar, now removed.

my question - is my inability to fine tune due to cable tension (as opposed to limit screws), and, if so, does anyone know where I can get a in-line tension device? The frame has guides on the down tube where the housing sits in. I did a bit of searching last night but could not find anything.
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Old 02-23-10, 09:25 AM   #2
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I don't have experience with Sora but as far as I know all Shimano triple front shifters have 4 main positions for the 3 chainrings, plus most have an additional trim position for the smallest chainring. This means that for each chainring there are two usable positions for trimming the front derailleur.

The front shifter cable should have little if any cable tension when the derailleur is set for the smallest cog.

The factory grease used in STI shifters hardens with time. Flushing them out with WD40 or similar often restores good performance.

STI shifters don't like dirt or water.

Al

Last edited by Al1943; 02-23-10 at 09:37 AM.
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Old 02-23-10, 09:33 AM   #3
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If you cannot successfully shift down from the big to middle rings, then it sounds like you have too much tension on the cable, which would go hand in hand with the derailler rubbing the chain when using the middle ring. The derailler is positioned too far towards the big ring due to too much tension. The derailler's position over the middle is completely dependent upon cable tension which is why so many people have trouble setting up triple front deraillers. The little and big ring positions are dictated by the high and low stop screws, though with too much tension, it's possible to have the front derailler not completely return to the low limit screw (I wouldn't be surprised if that was occurring on your bike right now).

For me, I've always relied on having an inline adjuster for setting up a triple FD. I've done it without but it wasn't fun and I wasn't 100% happy with the results either. You can find inline adjusters from Nashbar or several other vendors. Here's a few links:

http://www.nashbar.com/bikes//Produc...2_175228_-1___
http://www.universalcycles.com/shopp...php?category=7 (scroll down to "Cable Adjusters")

Edit: As far as I know, Sora 8 speed triple shifters only have a trim position for the inner ring to allow you to use the small cogs. Make sure you have fully let out the cable before attaching it to the FD otherwise you'll be scratching your head as to why you can't get the adjustment right.
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Old 02-23-10, 09:40 AM   #4
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I did a similar conversion to a MTB. I'm pretty sure my Sora triple has no trim adjustment. Anyway I needed to get an inline adjuster. Jagwire makes them along with others. I mounted mine a couple inches from the shifter figuring it would be easy to reach while riding. Pretty much need two hands to work it though.

They weren't expensive and I got some small ones that aren't very obtrusive. Maybe that's why I need two hands to work them. Anyway I'm happy with them and they're well worth it.

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Old 02-23-10, 09:44 AM   #5
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There is definitely a trim position for the inner ring on Sora 8 speed triple shifters. I honestly haven't played around with them enough to know if there are more trim positions only because a. I no longer use them on any of my bikes and b. on my wife's bike with Sora shifters, the middle and big ring can use all cogs without trimming. Maybe tonight I'll put it on the stand and confirm the lack of middle and big trim positions. FWIW, my Ultegra 9 speed triple shifters don't have a big ring trim position either.
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Old 02-23-10, 09:49 AM   #6
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Quote:
Originally Posted by joejack951 View Post
, my Ultegra 9 speed triple shifters don't have a big ring trim position either.
But you could use the 3rd main position for trimming on the big ring if you ever needed it, unlikely that you would though.
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Old 02-23-10, 10:03 AM   #7
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Quote:
Originally Posted by joejack951 View Post
If you cannot successfully shift down from the big to middle rings, then it sounds like you have too much tension on the cable, which would go hand in hand with the derailler rubbing the chain when using the middle ring. The derailler is positioned too far towards the big ring due to too much tension. The derailler's position over the middle is completely dependent upon cable tension which is why so many people have trouble setting up triple front deraillers. The little and big ring positions are dictated by the high and low stop screws, though with too much tension, it's possible to have the front derailler not completely return to the low limit screw (I wouldn't be surprised if that was occurring on your bike right now).

For me, I've always relied on having an inline adjuster for setting up a triple FD. I've done it without but it wasn't fun and I wasn't 100% happy with the results either. You can find inline adjusters from Nashbar or several other vendors. Here's a few links:

http://www.nashbar.com/bikes//Produc...2_175228_-1___
http://www.universalcycles.com/shopp...php?category=7 (scroll down to "Cable Adjusters")

Edit: As far as I know, Sora 8 speed triple shifters only have a trim position for the inner ring to allow you to use the small cogs. Make sure you have fully let out the cable before attaching it to the FD otherwise you'll be scratching your head as to why you can't get the adjustment right.
Thanks to everyone who responded, and in particular this post, which I think hit it on the head. The i've got the tension high on the cable, and that must be my problem.

I've also messed up and cut the cable too short (cue head slap) and so i'll be ordering a new cable along with an in-line adjuster.
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Old 02-23-10, 10:18 PM   #8
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Quote:
Joejack951
There is definitely a trim position for the inner ring on Sora 8 speed triple shifters
.

It depends on the year they were made. Mine definitely do not have a trim position. They are older 8 spd.
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Old 02-24-10, 07:38 AM   #9
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Originally Posted by Doug64 View Post
.

It depends on the year they were made. Mine definitely do not have a trim position. They are older 8 spd.
How old?
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Old 02-24-10, 11:57 PM   #10
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Joejack951,

It must be at least 6 or 7 yers old. I know when I downloaded some tech info on the Sora FD from the Shimano website, they talked about a trim position. I just assumed it was on the newer models. I think the suggestion of putting in an inline cable adjuster is a good idea. There is really not a good way to fine tune without it.

FWIW-- When I bought the bike, I assumed that I'd be replacing the Sora components in a short time because it was my every day ride. I ride that bike almost every working day, and it still shifts as good or better than my "good" bike. I also like the thumb lever better than the integrated levers on the Tiagra, 105's.... I am replacing my wife's Tiagra's with some short reach levers and thought about converting my 8 speed to a 9 speed using her old levers. But only for a few seconds-- why would I want to screw up something that is really working well with an unknown!
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Old 02-25-10, 12:35 AM   #11
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anything regarding the movement up and down of the derailler in the front has to do with cable tension, if you cant adjust the FD cable tension you are SOL and should just buy a new bike, and chain rub can be due to the angle of the FD needs to be aligned better or you need to fiddle with the limit screws, or you might need to trim the derailler using shimanos trimming function, basically go up to your large ring and click the downshift lever but slightly it should have one click do not push the lever fully thou or you will shift the derailler, what trimming does is physically move the FD using idk what but it physically moves the derailler toward the frame the more you click on the shifter the more it goes toward the frame rather than away from the frame.
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Old 02-25-10, 09:15 AM   #12
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you said "fine tuning" and "Sora triple front derailer"

In the common 8-speed version (which sounds like what you have) I think there are only 3 stops (one for each ring, no trim) and many people find it difficult to get it adjusted perfectly. You can play around with the barrel adjuster and limit screws, or just switch to a down-tube or bar-end shifter for the front
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Old 02-25-10, 09:16 AM   #13
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Quote:
Originally Posted by FR4NCH1SE View Post
if you cant adjust the FD cable tension you are SOL and should just buy a new bike,
No, you add an inline adjuster.

Quote:
Originally Posted by FR4NCH1SE View Post
and chain rub can be due to the angle of the FD needs to be aligned better or you need to fiddle with the limit screws, or you might need to trim the derailler using shimanos trimming function, basically go up to your large ring and click the downshift lever but slightly it should have one click do not push the lever fully thou or you will shift the derailler, what trimming does is physically move the FD using idk what but it physically moves the derailler toward the frame the more you click on the shifter the more it goes toward the frame rather than away from the frame.
Trimming uses the same mechanism for moving the front derailler as does normal shifting. The cable is slightly pulled or released to change the position of the FD.
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Old 02-25-10, 09:23 AM   #14
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Quote:
Originally Posted by TallRider View Post
you said "fine tuning" and "Sora triple front derailer"

In the common 8-speed version (which sounds like what you have) I think there are only 3 stops (one for each ring, no trim) and many people find it difficult to get it adjusted perfectly. You can play around with the barrel adjuster and limit screws, or just switch to a down-tube or bar-end shifter for the front
Shimano tech docs agree with my experience. The Sora triple shifters have a single trim position for the little ring only. Apparently, the double versions have a trim position only for the big ring. Read up:

http://techdocs.shimano.com/media/te...9830682074.PDF

With short-ish chainstays, it may not be possible to use the full width of the cassette when in the middle ring due to the lack of a trim position. In that case, you'll need to decide between having clearance for the big end of the cassette or small end. Adjust the cable tension as necessary to position the FD where need to get clearance for your preferred gear combinations.
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