I just do not know how to adjust a front deraillure

JimmyK

Ive watched instruction videos and still wouldnt attempt to do the adjustment because i would make an absolute hash of it.

my trek1000 is double front ring, 8 speed and rear cassette is shimano 12-23.

the bike, if i was on outer front ring at front and changed to high gears on rear cassette and inner front cog, started throwing the chain off. a guy adjusted it so it would not throw the chain off irregardless of any gear change I executed, but this resulted in slight rubbing at the front deraillure.

id dearly love to know how to do the fix without resorting to LBS, is there any guide out there for technical numpties just like me that would help ?

JimmyK

gundersen

hang the bike up
there are 2 skrews
1 to stop inwards travel
the other to stop outwards travel

so now you turn the crank and with a screwdriver adjust the screws
experiment
thats how you understand whats happening

when you have finished playing you should be able to shift to the big ring without the chain falling off, and back to the small ring without it falling off.

thats all there is to it

redvee

Parktools!

bahzob

Parktools site very good but does not mention "trimming" option that some shifters have to let you fine tune the derailleur to avoid chain rub.

As well using the Parktools site its worth refering to the original manufacturer's intallations intructions. e.g. Ultegra below.


http://techdocs.shimano.com/media/techdocs/content/cycle/SI/SI_5JD0A_001/SI_5JD0A_001_En_v1_m56577569830616200.pdf

grahamharpin

I adjusted the front on my bike yesterday after fitting a new bottom bracket, it is a triple chainset but adjustment is similar.

Lift the bike so the pedals will drive the wheel
Slacken off the cable tension, this will move the mech to the smallest chainring.
Shift rear to largest sprocket
Adjust lower stop screw so there is about 1 mm clearance between chain and front mech cage.
Tighten cable again as far as it will go
Shift to biggest chainring & smallest rear sprocket
Adjust upper stop screw until the change up to the big chainring is easy and does not overshoot.
Set rear sprocket to middle of the cassette
Change down to lowest chainwheel, if the cable was really tight it probably will not change down so gradually relaase cable tension until it changes cleanly.
Check change over both (or 3) chainrings.

bahzob

grahamharpin wrote:

I adjusted the front on my bike yesterday after fitting a new bottom bracket, it is a triple chainset but adjustment is similar.

Lift the bike so the pedals will drive the wheel
Slacken off the cable tension, this will move the mech to the smallest chainring.
Shift rear to largest sprocket
Adjust lower stop screw so there is about 1 mm clearance between chain and front mech cage.
Tighten cable again as far as it will go
Shift to biggest chainring & smallest rear sprocket
Adjust upper stop screw until the change up to the big chainring is easy and does not overshoot.
Set rear sprocket to middle of the cassette
Change down to lowest chainwheel, if the cable was really tight it probably will not change down so gradually relaase cable tension until it changes cleanly.
Check change over both (or 3) chainrings.

Great summary, worth putting in FAQ somewhere.

Would only add in case of continued problems following above after step "shift to biggest chainring/smallest sprocket:"
- Check outer of mech cage is exactly parallel to chainring
- Check gap between bottom of mech cage and teeth on largest chainring. Should be 1mm.
-- If either not the case adjust mech cage to correct and restart procedure.

gkerr4

this is a god summary above^^

one of the best set of documents I have found is shimano's own techdocs section which you wil find here:
http://techdocs.shimano.com/techdocs/index.jsp

hover over road and select the groupset you have (tiagra is it on the 1000?) - then select the front derailler and (FD4400 or FD4500 - the xx03 models are for triple specific front mechs)

there is an excellent section on there for setting up the front mech