Front Derailleur

[Alan Farroll]

Hi,

One of my bikes is a Giant Talon 4 2014 and my gears were playing up so decided to tune them. I have performed the front derailleur tuning on another bike okay but I cannot seem to get the front derailleur to tune in on this bike no matter what I try. Please help. Front derailleur is a Shimano Altus.

I have performed the following;

Tuned the rear derailleur first
Checked height of front derailleur is about 2 mm above large crank (triple crankset) and is parallel with the largest crank too
Placed chain in smallest crank and largest sprocket (also tried chain in smallest crank and smallest sprocket and smallest crank and in middle sprocket)
Released gear cable and wound barrel shifter almost all the way in
Adjusted inner setting screw till inner plate of derailleur is about 1mm from inside edge of chain
Refitted gear cable
THEN when I try to move chain to next largest crank the following seems to happen;

• The chain keeps slipping off the center crank but will go to the largest crank. But when changing down it slips straight from largest to smallest crank
• Or I can get the chain to go to the center crank but will NOT go over onto the largest crank

I have tried every adjustment I can think off but nothing works. What am I doing wrong please?

Thanks in advance

 

[raleighnut]

You need to set the cable tension so that on the middle ring (with that selected on the shifter) the derailleur is centred on the middle ring. The inner and outer are set by the stops but the middle ring is indexed by cable tension only.

 

[Alan Farroll]

You need to set the cable tension so that on the middle ring (with that selected on the shifter) the derailleur is centred on the middle ring. The inner and outer are set by the stops but the middle ring is indexed by cable tension only.

Thanks raleighnut. So if I get the derailleur working on the smallest crank and the largest crank then I should leave the limit screws alone and adjust the cable tension so it works with the middle crank??

 

[the snail]

Put the derailleur into the granny ring, loosen the cable take out slack and retighten, then adjust the tension so that it will change onto the middle ring cleanly, then adjust the limit screws if necessary so that you can change to inner/outer without the chain coming off. You may need to tweek things a bit to avoid chain rubbing, bearing in mind you may have a trim function on the shifters, and on extreme gear combos some rub is often unavoidable on a triple.

 

[raleighnut]

Thanks raleighnut. So if I get the derailleur working on the smallest crank and the largest crank then I should leave the limit screws alone and adjust the cable tension so it works with the middle crank??

Yep, follow the snail's procedure above.

EDIT there may be some cable slack on the granny ring though, don't worry if there is as long as the limit screw prevents the mech moving too far in

 

[Alan Farroll]

Put the derailleur into the granny ring, loosen the cable take out slack and retighten, then adjust the tension so that it will change onto the middle ring cleanly, then adjust the limit screws if necessary so that you can change to inner/outer without the chain coming off. You may need to tweek things a bit to avoid chain rubbing, bearing in mind you may have a trim function on the shifters, and on extreme gear combos some rub is often unavoidable on a triple.

Thanks for feedback. So if after ensuring height and alignment is correct. Then in granny crank and largest cog set limit on inside chain edge. Take up slack in gear cable and adjust barrel shifter to move smoothly into centre crank. Then adjust outer limit for smooth shift to large crank???