105 Triple System Front Derallieur Problem - Help Please :-)

Lspringett

Hi, been riding for a while now but never really got my head round much maintenance.

Anywho, got a new (used) bike for xmas that's fitted out with a 105 triple system. Everything else seems to be running well however been getting some issues with the front mechs.

What I'm finding is that in the smallest gear in the front (believe to be the granny) all seems good, no rubbing up front and can switch between the full set on the back.

But then the problems start...

When I try the move to the middle cog up front, depending on which gear I am on on the rear it will either move. up or just keep slipping until I give the shifter another click then click it back down again to the second position.

The same happens when I try to move into the big (daddy?) up from, if I'm on the smallest cogs on the rear it moves up but anything from cog 4 - 10 it just doesn't want to switch up.

I've read around that with triple their quite a range of front/back combinations that will cause issue/rub, but this seems quite strange.

Taken to lbs who shifted the derailleur up and said he'd reset/adjusted the tension up when I got out on it, the above happens. Also noted its seem much worse when once trainer as opposed to the road.

Any help, advise gratefully received, pretty sure it's a trip back to the lbs.

brucey72

It sounds like you might have to increase the cable tension on the front derallieur (sp?). You can do this with the barrell adjuster.

Lspringett

Cheers, is this the black nobly bits on the cable by the shifters? How do I use them as different bits seem to rotate.

Thanks

brucey72

I'm not sure that is them. They are 'black nobbly bits' but mine are set on the frame and allow you to fine tune both the front and rear deralieurs whilst on the move. Have a look at this website which should explain things a lot better than I can ;-)

http://www.parktool.com/blog/repair-hel ... djustments

keef66

Have a look on the Shimano website and read the instructions for the triple front derailleur, especially the section on the trim function. It may well be working as intended or just need a small adjustment.

I have a 5603 triple. On mine if I shift from the granny ring it takes quite a wide sweep of the lever to get it onto the middle ring. This is the position for the smallest 8 cogs on the cassette but there's slight rubbing on the cage if I use the 2 largest sprockets. However, with a small click on the downshift paddle it trims, ie moves the cage back a bit so I can use the biggest sprockets without rubbing. Same applies to the biggest chainring.

Lspringett

Thanks guys, it appears the trimming is setup and defiantly helps with the middle ring, but still doesn't want to move to the daddy, I push the shifter, the Derallieur moves but I just feel resistance on the shifter and once it clicks, it hasn't moved the chain up. The bike doesn't appear to have barrell adjuster on the cable on the downtube so will take back to my lbs to have another look.

tim_wand

There are certain gear combination where the chain alignment will cause rubbing. and the same gear came be achieved by running a combination of another ring on the front and back, However to loose "4" cogs on the rear is extreme, I ve never personally suffered from this in anything other than Top Bottom and Bottom Top.

If your problem is moving up to High range gears on the front then let some tension off the high range screw on the front mech (right side outer phillips head screw). work in quarter turn increments and you should visibly be able to see the mech moving to the right and the gap between the plate and the chain on the inside plate closing up.

Using the barrel adjustments on the Stis . Cable adjusters or Frame mounts (whatever system you have) will further fine tune this and allow you to take out any cable stretch and index the gears, but you need to make sure the limit screw adjustment on the front mech is correct first. You can do this by manually pulling the cable from in front of the bottom bracket/ down tube and checking the swing and chain alignment.

I d also check if the gap between the outer plate of the front mech and outer chainring is correct as well. It should be 3-5mm . New mechs come with a little red sticker with the chainset teeth superimposed on them showing the correct mech height.