Classic & Vintage - downtube friction shifters slipping

This is in regards to Campagnolo C-Record downtube friction shifters.

The shifter for the rear derailleur is slipping, especially in the lower gears. For example, when I'm on the largest rear cog (lowest gear) the shifter lets the derailleur slip towards the next cog, ever so slightly, and very slowly. It never slips enough to ghost shift, but just enough to cause excess drivetrain noise. When riding, I occasionaly have to pull back on the shifter to bring the derailleur back into alignment with the gear I'm in. I've tightened the shifter down as much as I possibly could. Is there anything else I can do to help fix this problem? Again, this is DT friction shifting.

Take it apart and clean the interface between the shifter and the washer. You may need to find a new washer if it too worn out.

There's really not much to a campy friction shifter. I'm thinking you could maybe take it apart and look at the brass or plastic washers in it. You know, like trying to visualize whats causing it to slip. Could be these washers are worn, and maybe lubricated too much to cause slipping. That be my guess. You could also try flipping the washers over and see if that might fix it.

Apparently you cant get enough "friction" in the shifter to overcome the spring pull of the derailleur.

I have this same problem with a pair of NOS Record/Nuovo Record (brass bushing) downtube shifters used in conjunction with a '61 Campagnolo Gran Sport RD.

Take care,

-Kurt

If it is only slipping while in the lowest gear (largest rear cog), then you may be able to get a little relief by relaxing the travel limit screw (for adjusting the limit of travel for the rear derailleur, toward the spokes) just a tad. In other words, let the rear derailleur move just a little bit past dead-center on the largest cog, before it hits the stop. (But don't allow it to move so far that you risk dropping the chain next to the spokes.)

I had the same problem with the Suntour friction shifters and rear derailleur on my bike, and the above helped a lot. Of course a bit of tightening down of the friction adjust will also help, but it will make it stiffer-feeling in all gears.

One other idea is to find a ratcheting shifter for the rear. These are still friction shifters, but the ratchet mechanism means that they are stiffer to move from low to high (i.e., stiffer in the direction your shifter is slipping), but easier to move from high to low gears. Basically they are easier to move when you are pulling against the spring force of the derailleur, and stiffer when you are going in the same direction as the spring force, which serves to sort of even out the overall effort. I guess I don't know if Campy made a down-tube friction shifter with a ratchet mechanism. But Suntour made their friction shifters in both forms - straight friction, and the so-called "power shifters" with ratcheting. (The ones I have seen have had the ratcheting only on the right shifter for the rear, and straight friction for the front derailleur, where you are having to do more tweaking of the derailleur position.)

These will solve the problem:
http://thumb9.webshots.net/t/53/453/1/52/56/2776152560068014369ruuGdD_th.jpg (http://sports.webshots.com/photo/2776152560068014369ruuGdD)