Front derailleur not shifting properly

[srixon]

Hi - I've had my road bike (an '08 Specialized Roubaix that I bought used) for about a year and am doing my best to do my own maintenance and repairs. I just came across this site and it looks like there's a ton of good info here!

I'm having some trouble with my front derailleur (or maybe shifter?). I am pretty sure the derailleur is properly adjusted, but I could be wrong. I seem to have to put quite a bit of force on the lever to move to a higher gear (largest chainring), and when I do shift up the chain seems to grind a bit and have trouble catching.

When I shift down from the largest chainring, the shift lever (Shimano 105 STI) it feels like a lot of tension gets released and it will sometimes jump all the way down to the lowest gear. Other times it will shift down to the middle chain ring, but from here I will try to shift down again and it won't get to the lowest gear.

The chain, cassette, and middle chainring are all new (if that makes any difference).

As I write this, it really seems to scream "derailleur needs adjustment!" but I've tried tinkering with that plenty with no success. Could it possibly just be the tension in the front derailleur cable it too high?

Any help is VERY appreciated!

[trevgbb]

This is the product tech doc page for 105, you will find all the set up info here, but one of the commonest and least regarded fault is that the changer is set too high or too low, that is assuming the stops are set correctly and the cable is free, the other common fault is alignment;
http://techdocs.shimano.com/techdocs/blevel.jsp;jsessionid=MJZhPxtQHFL9BDVRbvTR2yP9QJMQYQwhpHkybFrNWqfBRw6hzQ1v!-1800374902?FOLDER%3C%3Efolder_id=2534374302051113&bmUID=jsFxpzh

[Joe_W]

(05-14-2012, 08:38 AM)srixon Wrote:  As I write this, it really seems to scream "derailleur needs adjustment!" but I've tried tinkering with that plenty

Ah, yes. That might be it ;-)

Do you have three or four chain rings?
Are you sure the "trim" step is set up correctly? There is some Shimano techdoc that states which shifter / FD has the trim step at which position, but I cannot find it at the moment.

[srixon]

(05-15-2012, 07:33 AM)Joe_W Wrote:  

(05-14-2012, 08:38 AM)srixon Wrote:  As I write this, it really seems to scream "derailleur needs adjustment!" but I've tried tinkering with that plenty

Ah, yes. That might be it ;-)

Do you have three or four chain rings?
Are you sure the "trim" step is set up correctly? There is some Shimano techdoc that states which shifter / FD has the trim step at which position, but I cannot find it at the moment.

Thanks for the idea Joe_W (I have 3 chain rings, byt the way). I found the techdoc that discusses trim setup so I'll give that a try tonight. (http://techdocs.shimano.com/media/techdocs/content/cycle/SI/105/FD_5600/SI_5JM0C_001_EN_v1_m56577569830621301.PDF)

While playing around with it last night (adjusting the derailleur, AGAIN), I noticed that when doing a full shift from the smallest gear to the middle chain ring (i.e. I push the left shifter in towards the bike as far as it will go), so derailleur doesn't move the chain quite far enough for it to grab the middle chain ring - I have to release the shifter and give it an extra little push to get to the gear. So then my thought was that the cable needed additional tension perhaps, but it was late and I was tired of tinkering with the bike. Any additional thoughts based on that info?

[Joe_W]

Hm. I also found the 105 on my road bike a bit ... tiring (you said so) to set up. You have to make sure that (without cable tension) the lower limit is as high as possible, with the chain just not rubbing. Then, carefully increase cable tension and look at up-/downshifting behaviour. Shift several times and observe. Recheck lower limit. Repeat ad nauseam. All of a sudden it will work.
Starting from the beginning (slack cable) helps a lot in the process! Good luck and enjoy riding! I had my first longer ride of the season this Sunday (100km), weather was great, landscape was nice but my legs are not used to this.

[srixon]

(05-15-2012, 09:44 AM)Joe_W Wrote:  Hm. I also found the 105 on my road bike a bit ... tiring (you said so) to set up. You have to make sure that (without cable tension) the lower limit is as high as possible, with the chain just not rubbing. Then, carefully increase cable tension and look at up-/downshifting behaviour. Shift several times and observe. Recheck lower limit. Repeat ad nauseam. All of a sudden it will work.
Starting from the beginning (slack cable) helps a lot in the process! Good luck and enjoy riding! I had my first longer ride of the season this Sunday (100km), weather was great, landscape was nice but my legs are not used to this.

I'll give it another whirl tonight! When I was adjusting the derailleur previously I did not release the tension bolt, so the cable was not slack. Hopefully doing that and going through the adjustment process will take care of things.

Thankfully I can get out to ride the bike and still get a decent range of gearing by staying in the middle chain ring - but it sure would be nice to add some hills and pick up more speed in the flats. Fingers are crossed that I can get it resolved tonight. Thanks again for the input

[RBurrelli]

(05-15-2012, 09:50 AM)srixon Wrote:  

(05-15-2012, 09:44 AM)Joe_W Wrote:  Hm. I also found the 105 on my road bike a bit ... tiring (you said so) to set up. You have to make sure that (without cable tension) the lower limit is as high as possible, with the chain just not rubbing. Then, carefully increase cable tension and look at up-/downshifting behaviour. Shift several times and observe. Recheck lower limit. Repeat ad nauseam. All of a sudden it will work.
Starting from the beginning (slack cable) helps a lot in the process! Good luck and enjoy riding! I had my first longer ride of the season this Sunday (100km), weather was great, landscape was nice but my legs are not used to this.

I'll give it another whirl tonight! When I was adjusting the derailleur previously I did not release the tension bolt, so the cable was not slack. Hopefully doing that and going through the adjustment process will take care of things.

Thankfully I can get out to ride the bike and still get a decent range of gearing by staying in the middle chain ring - but it sure would be nice to add some hills and pick up more speed in the flats. Fingers are crossed that I can get it resolved tonight. Thanks again for the input

Finer tension adjustments are usually made with the barrel adjusters. If those are not in a good position when you start your adjustments (too tight) then it might be a good idea to have them all the way "loose" when you start with the slack cable. Then tension can be increased later. Hope that makes sense.

[Joe_W]

Remark: for the rear dérailleur I usually start with the barrel adjuster not all the way loose... but in general it is true: you are much more likely to want to increase cable tension rather than decrease.

[srixon]

Thanks for all of the help and suggestions. Last night I essentially removed the derailleur and started the installation from scratch but again had no luck. At this point I think it's time to suck it up and bring the bike over to my LBS for them to have a look and hopefully fix it up quickly and inexpensively.

[bikeh]

Any help is VERY appreciated!
[/quote]


Make sure your chain is on the innermost rings when you adjust the cable tension. Just made that mistake: I tightened the shifter cable from the larger ring and I couldn't shift on the lower 6.

[Palash]

My Front gear is not shifting......... How to fix it?????