Roypercy

Hey all; in another post I mentioned my ongoing struggles with the Simplex SX610 derailleurs on my 82 Grand Jubile. At the time I was considering replacing the rear derailleur due to shifting problems, and was about to replace the shift levers because (I thought) the front shift lever wasn't holding tension and was causing the front derailleur to spontaneously shift to the smaller chainring.

So last weekend I spent some time on bike maintenance. I installed new-old-stock Campy levers and new derailleur cables, and cleaned and lubricated the Simplex units front and back. Lo and behold, the rear derailleur now shifts like a champ. The front, however, still spontaneously wants to go onto the lower chainring, and I see now that it's actually dragging the front shift lever with it when it goes. I've tried adjusting the cable tension, tried working with the adjustment screws. The only thing I was able to do was adjust it so the front derailleur literally cannot go onto the smaller chainring. This is fine in a way since I rarely use the smaller front chainring anyway, but I'd like to have the option. I've never had this happen on any bike, or had so much trouble dialing in a front derailleur.

So, those of you who are better mechanics than me (which includes pretty much everybody!) what's going on? Is the derailleur shot? Am I overlooking something?

Thanks for any help, advice or commiseration

TenGrainBread 

Is the FD shift lever appropriately torqued onto the frame? Every time this has happened to me it's been because I haven't tightened it down enough, letting the lever get pulled back by the derailleur. You need to be careful not to over- or under-tighten.

coolkat

Increase friction on the lever

Roypercy

The lever's as tight as it will reasonably go without over-tightening, and after I disabled the derailleur from moving, the lever hasn't budged. I don't think it's the lever.

satbuilder 

Are you sure the cable is not losing tension? If so, it might be something as simple as the gear shift tension screw bottoming out on the braze on before adequate tension is met.

JohnDThompson 

Are perhaps missing a piece from the shifter?

SkyDog75

If the derailleur's spring tension is overpowering the friction in the lever, it is the lever.

repechage

take the cable tension need out of the system by detaching the cable at the derailleur, assess the friction of the shifter.
If these are the clamp on Campagnolo levers, pretty predictable if all the parts are there and in proper place. If the later unit with the nylon internal compression washer, double check the qty of washers under the D ring bolt. Those often need two.

repechage

Yes, but not for the second generation with the plastic compression washer that replaces #174

Roypercy

Well,live and learn. I just reset the levers, readjusted the cable tension and readjusted the derailleurs. I set the levers tighter than they were before, and it seems to have done the trick. Thanks, all!