UKC

All,

I am new to maintaining bikes, so excuse the lack of knowledge in language, and recently been given a road bike i been training for fitness for alpes on. It was pretty well set up, by friend who looks after own bikes and engineering mind. however it has probably not been used for a few years and i've done a good 300 miles over last few weeks until front gears went mad. First would not drop into low gear, then high gear, and need tapping into gear true to stop rattling.

I have replaced cables and reset back der fine, from an idots guide, which I got right so very simple. front der seems ok condition, good action, all bits tight no wobble and and a good resitance. I have set both high and low limits fine with ease.

Shifter are shimano Tiagra, back shifter indexing fine. i think Front shifter appears to index fine when not linked to der. However when using main lever first fine, second seemed to have no real index just free movement. When under tension just seems to do its own thing, sometime tight, sometimes very slack, no matter what combination of slack, tightness, just seems to have life of its own. I have spent more time on this than proper work, but im determined to not spend money i dont have on bike repair shops.

Stupid question now? is it my stupidty with mechanics, or do you think shifter is shagged, i have read that lots of issues with front shimano shifters, some component breaking inside unit. Any tech advice or is it a case of new shifter.

all help appreciated, Rich

In reply to r.greaves:

does the cable run freely through the cable housings and no snags?


other than by direct damage ive not had any problems with a shifter but ders can die over time especially if not used for a while. they are quite cheap to replace, thats what id look at next, no problems with shimano for me.

In reply to r.greaves:

Do you have 2 or 3 chainrings on the front?

First make sure everything is oiled correctly, especially the cable housing and the derailleur spring. Check that the derailleur moves cleanly and springs back into place without the cable attached. Then make sure the cable is attached properly, no slip.

What shifter is it?

In reply to r.greaves:

Sounds like the shifter end of the cable isn't seated correctly in the shifter or is perhaps the wrong style cable end (does it fit snugly in the shifter?) or there is something wrong with the routing of the cable.

Did you replace cable outers? Its easy when cutting them to crush the ends and leave a burr that a cable to catch on occasionally. If you didnt replace them, they could be full of crap thats causing the problem.

To test the shifter, attach the cable to it, and apply tension on the cable without threading it so the only thing in the sytem is the shifter, the cable and your hand. Do the levers act like you expect? On my 105 shifter (a double) when the shifter is in granny ring position then the small lever moves the full throw without any indexing. I only get indexing from the big ring position or the intermediate "trim" position if that helps.

With the cable detached can you manually move the deraileur through the whole range of movement does it move without any noticable change in force other than what youd expect from compressing a spring? Check for stones/grit in and around the moving parts

...desperately trying to remember the name of the good website written by a cyclist that died a few years ago named after the cyclist (its a slightly unusual name iirc), he goes into really good detail on how to solve front deraileur problems... some one put me out of my misery!

In reply to balmybaldwin:

Sheldon Brown! http://sheldonbrown.com/home.html

In reply to balmybaldwin:

http://sheldonbrown.com/

Possibly?

In reply to r.greaves:

This is another good site that covers most bike basics

http://www.madegood.org/bikes/repairs/

In reply to r.greaves:

http://www.parktool.com/blog/repair-help

This can be a good resource too at times.

In reply to TobyA:

Thank you!

In reply to r.greaves:

Fitted a new Tiagra triple at Easter. I thought the shimano docs were quite good and after a couple of attempts it now runs very smoothly.

http://techdocs.shimano.com/media/techdocs/content/cycle/SI/TIAGRA/FD-4503/...

Good luck.