Problem adjusting 105 front derailer

mistergoof · Post by **mistergoof** » 21 Apr 2007, 3:36pm

I'm having a problems adjusting my 105 front derailer.

In simple terms, I turn the bike upside down adjust Low and Top adjustments run gears through all OK

Turn bike back up the correct way and have problems getting from the smaller chainring to the larger.

Aaarrrgggggggggg !

thanks

MG

thirdcrank · Post by **thirdcrank** » 21 Apr 2007, 5:10pm

If I have understood you correctly, the adjustments you are making are to prevent the front mech., changing too far in either direction and have no effect on the change between chainwheels.

I think that difficulty moving from the smaller chainwheel to the larger is likely to be caused by either the cable not being properly adjusted or the mech., being wrongly positioned.

Post by **Mick F** » 21 Apr 2007, 5:12pm

I know little about 105's, let alone Shimano!

But I feel it's all to do with "Dynamics". You can set something to work in a static environment, but it the "real" world, it won't work properly. Upside down is not the way you ride, and with weight on the bike, the frame will settle somewhat.

Try taking a screwdriver with you on a test ride. Adjust a bit at a time, as you go, testing all the time. It may work! Good luck!

Post by Si » 21 Apr 2007, 5:19pm

To follow on from Mick's point - when doing gears I mount my bike in the turbo-trainer, then I can test it under load without having to take it for a ride.

PW · Post by PW » 21 Apr 2007, 11:31pm

The 2 grub screws prevent the mech overthrowing in or out. The adjustment is all down to cable tension. If it still won't work - and I've had a ta-ta with 105 on a triple - then try tweaking the toe in/out angle as you look down from above. It doesn't need a lot! Finally make sure the outer cage plate is as close to the top of the outer ring as possible without fouling the chainwheel teeth.

mistergoof · Post by **mistergoof** » 22 Apr 2007, 4:10pm

OK
I've fashioned a device (table / ladder);dont laugh; so I can adjust the gears with the bike the right way up.
What I've done using http://techdocs.shimano.com/media/techdocs/content/cycle/SI/105/FD-5500-5501/SI-59G0C-En_v1_m56577569830612176.pdf and http://techdocs.shimano.com/media/techdocs/content/cycle/SI/105/FD-5500-5501/SI-59G0C-En_v1_m56577569830612176.pdf (as these are slightly more deatiled, although mine is the 18 spd one)
1) chain on small front and large rear
2) adjusted the low screw (nearest the frame) so that the chain is about 0.5mm from the inner plate
3) I have managed to remove the top screw and still it wont go onto the out front ring. And that damn trimming thing, well aarrrggghhhhhh

I don't really want to take it to a shop as I want to learn but hey I might just have to.

any more tips.

PW I'm being a bit dim can you translate your post into something that a simple sole like myself may understand

ta

MG

georgew · Post by **georgew** » 22 Apr 2007, 5:53pm

Have a look here and you will find what you're looking for.
http://www.parktool.com/repair/byregion.asp

thirdcrank · Post by **thirdcrank** » 22 Apr 2007, 6:48pm

http://sheldonbrown.com/derailer-adjustment.html#front

You could also have a look at SB

PW · Post by PW » 24 Apr 2007, 11:38am

Mistergoof, if you look down on the mech from above, the 2 plates containing the chain (the cageplates) are supposed to be parallel with a straight line through the frame from steering head to saddle. If you twist the mech *very*
slightly so that it either looks "toed in" or "toed out" it sometimes runs better. This is only a very gentle tweak, I'm not suggesting a huge twist.
Also the height of the mech above the chainrings makes a lot of difference. It needs to be as low down as you can get it without actually catching on the teeth of the chainrings.