Down Shifting intermittent

[doughavlin]

I have a TREK road bike I got used with some Shimano shifters. I'm not sure the model, but they're maybe 10 years old. It's the type of shifter that has the break and shifter all in 1. I move the whole thing inward to shift the front derailleur up to the big chainring. And flick the smaller lever to shift down.

Lately going from the bigring down to small has been difficult. Sometimes I have to flick it 10-20 times before it clicks. I've tried adjusting everything, and I've noticed that it doesn't move the cable at all...there's no slack in the cable at all.

Once it gets into the small ring, i can upshift with no problem at all. That leads me to the innerworkings of the shifter, but there doesn't seem to be much to adjust there.

I'd like to learn how to fix it, but I seem to be coming up short. Any advice would be greatly appreciated.

Doug

[TESTUser111]

I'm guessing there might be some gunk inside the shifters that is causing them to mis-shift. <a href="http://bikeride.com/rapid-fire-shifters/">This video</a> may help understand what may be causing the problem. It's a completely different shifter but the same concept.

If that's not the cause, some of your shifter parts may actually be worn. It might be a good idea in this case to stop by your local bike shop and see if they can diagnose the problem better.