Shimano shifting issue

[wboftn]

I have an older Giant MTB with a Shimano STX rear derailleur.
The issue: The rear derailliur will not shift up to the larger gogs.

I installed a new shift cable and lubricated the derailleur. The cable moves freely when not attached to the derailleur.
I can get it to shift up to the larger cogs with the help of me pressing on the derailleur towards the bike.

It is like, there is too much pressure or not enough leverage to move the derailleur by just pressing the trigger shifter.

BTW, it shifts fine, coming down (large to small cogs).

Thanks in advance for your imput and help.

WB

[nfmisso]

sounds like you have the cable in routed incorrectly. Google "shimano tech docs" and look for the instructions for your derailleur

[RobAR]

Want to hear something funny that I see all-too-often? Mr A loans a bike to Mr B. Mr B notices that a screw is backing out on Mr A's bike and decides to help return the bike in better condition than he borrowed it from Mr A. An admirable trait.

If that screw is a Limit Screw on the rear drlr, Mr B just messed up.
Look for 2 small screws, marked H and L, on the drlr body. Loosen (counter clockwise) the L screw and report back.
I will bet a 5 pound Lasagna on it!

[wboftn]

Thanks for the imput RobAr and nfmisso. I study the tech docs and i do have the wire correctly routed. A have messed with the H and L screws along w/ the B screw and know their purpose. Seems to not make any difference - but I will try again tonight.
It seems to me, the springs in the drlr have too much tension for the trigger shifter. It will only move up to the next cog when I assist it by pressing on it.

[nfmisso]

Next guess - the trigger shifters are wearing out. Strictly a guess..

[Joe_W]

Is that "up to the next cog" in the sense of "to the next bigger one" (lower gear) or "the next smaller one" (higher gear)?

[wboftn]

"Is that "up to the next cog" in the sense of "to the next bigger one" (lower gear) or "the next smaller one" (higher gear)? "

Joe: Next bigger cog (lower gear)
Thx
WB

[wboftn]

"Is that "up to the next cog" in the sense of "to the next bigger one" (lower gear) or "the next smaller one" (higher gear)? "

Joe: Next bigger cog (lower gear)
Thx
WB

[Joe_W]

The cable is too slack. If shifting to the higher gears stops working then it can be the cables (routing, wear...) or gummed up shifters.

[Turkosaurus]

I have the same problem on a Klein I'm tuning up for my Dad. The shift lever only seems to have 5 indexed positions (only 5 "clicks"), weather the cable is connected or free. I believe that the derailleur on the bike is original, and meant to have 7 positions, but is only hitting 5. I have been able to adjust it to hit any 5 sprockets I choose, but only five.

What is going on here? Have you fixed your issue, wboftn?

Any help would be great.

BTW, I am also using a new shifter cable, and the bike seems sufficiently lubed, under ridden, and rust free.

[Bill]

Manually move the rear derailler back and forth with your hand and see if it will go to each of the seven "gears".

[Turkosaurus]

(10-27-2012, 11:02 AM)Bill Wrote:  Manually move the rear derailler back and forth with your hand and see if it will go to each of the seven "gears".

It has full freedom of movement to all seven when the rear derailleur is pressed manually, but the shifter won't move it onto the two biggest (slowest) gears. I have all the same problems as the thread initiator.

[Painkiller]

(10-27-2012, 02:27 PM)Turkosaurus Wrote:  

(10-27-2012, 11:02 AM)Bill Wrote:  Manually move the rear derailler back and forth with your hand and see if it will go to each of the seven "gears".

It has full freedom of movement to all seven when the rear derailleur is pressed manually, but the shifter won't move it onto the two biggest (slowest) gears. I have all the same problems as the thread initiator.

what exactly is the model/type of shifter do you have?