Shimano 600 SIS downtube shifter issue
I just picked up a Trek 470 with 600 (6207 series) components. The rear shifter isn't shifting correctly. When shifting into a bigger cog, if you push the shift lever to a certain spot, it will release about a mm or two of cable when you let go of the lever. This causes you to have to set the cable tension tighter than it should be to get it to stay in a gear.
in indexed mode, it shifts above the gear you want it, then settles back into the gear when you let go of the lever. In friction mode, if you push the lever just a little bit, it will release back to where it started when you let go of the lever, not shifting a gear at all. If you push it a bit further, it will release that same 1-2mm of cable once you let go of the lever.
Do I have a bad shifter? Am I forgetting something in the adjustments? Or were these old 600 shifters really this bad?
Thanks in advance
When installed properly and in good condition 600 and 105 indexing downtube shifters worked extremely well and reliably. Be sure the backing plate on your frame is oriented properly and that the SIS/Friction switch is set right. If both of these are ok, then it's possibly worn out.
What do you mean by backing plate? Are you talking about the piece that mounts the shifter to the frame boss?
Half round piece, behind the lever, it also stops the lever from going too far forward.
With a friction lever thats all it has to do.
Ok, the backing plate is oriented correctly. I'm kind of thinking it's worn out. I may throw on a different shifter and see if that fixes it.
Turns out the shifter was worn out. Half the teeth were broken. I threw on an old Suntour shifter and it shifts beautifully!
Those 600 EX rear shifteurs are famous for breaking the 6 or 8 teeth which stop the body of the friction unit from rotating. After they all break you are stuck in top gear. If you break off a piece of stick and stick it in between the downtube and cable you can select a lower gear, or even a small range by sliding the stick up and down. This is known as stick shift.
I imagine that to fix the breakingness problem the design had to change so the newer models can not be used to fix a 600EX one.
I have a busted right 600 EX shifter myself. The included downtube clamp with shifter bosses will be increasingly handy as our young folk express their personality by chopping shifter mounts off.
I'm going to put my good LH friction shifter with an orphan right STI. Maybe a broken left STI will turn up, but then plenty of women are happily living with one breast so I'll try not to feel too sorry for myself for having mismatched brakes ;-)