Shimano 105 left shifter is hard to shift?
 

I just started servicing my own bike recently, but i'm pretty good with a set of tools and so far have been able to take care of most maintenance issues.

I'm having a problem where the left shifter is hard to shift, if I loosen the derailleur cable from the FD, it's a bit easier but still requires quite a bit of force to push the lever/button used to upshift into a smaller front ring. It actually always shifts into the correct gear, it just requires a bit more force than other 105 shifters i've tried.

Is it a problem with the shifter, is there something I can do to adjust the force required, or something internal on the shifter that needs to be lubed?

I'd really appreciate any ideas.

see that the H screw on the derailleur isn't turned in to far - it will resist the derailleur's movement into the big ring. This theory is supported if you have derailleur rub in the big ring/small sprocket combination.

- Joel

I'll give it a shot, but with the cable completely removed from the FD, it's still feels stiff, which makes me think it's something in the shifter (I might be wrong though). Are there any tension adjustments on the shifter?

I'm going to try the H screw though, definitely can't hurt.

there may be something as simple as a kink in the cable resisting as it enters a piece of outer cable.

- Joel

This sounds likely as even if I disconnect the cable from the FD completely (leaving it just hang there), the shifter is still stiff (to upshift into a small ring on the FD).

I suppose i'll try taking the cable out of the FD completely and see what happens. Any other ideas on what could cause the shifting mechanism to be stiff?

From your description the problem can have nothing to do with the "H" screw. Best not to mess with it.

Try flushing out the shifter(s) with WD-40, use plenty. The next step will be replacing the shift cables and cable housings.

Al

Thanks Al ... Too late, I foolishly messed with the screws already, but that's okay, fine tuning the derailleur when i'm done should be all that bad. Thanks for the tips though, i'm going to try them out over the weekend.

This may seem obvious and you may already know this, but the left shifter will always seem harder because of the greater difference between the size of the chainrings.

If you need help adjusting the derailleurs I recommend the Park Tool site for instructions. It's important to do all of the steps in sequence leaving nothing out.

Al