Chorus rear derailleur high gear stop
 

I have in my hands a Campy Chorus rear derailleur from, I think, the mid-90s.

There is low gear adjustment stop that works but the screw next to it, which I assume to be the high gear stop, does nothing. There nothing for it to stop against.

I’m planning to install this derailleur on an old frame with down tube friction shifters so having limit adjustments is important.

Am I looking in the wrong place for the high gear stop?

Is there is missing part?

can you post a few pics? this is one for 8+ speeds?

The limit screws engage small tabs extend off the pantograph plates. The easiest way to see them in action is to flex the derailleur against the spring without the cable unattached. When flexed inward you'll see a tab touch the low limit, and when the spring returns it another tab will touch the high limit.

Note that when it's mounted the limits can be backed off because the cable will determine the positions, but they still need to be properly set to make sure that the RD cannot travel beyond the cassette in either direction.

I've had it in my hands on the work bench and now it's on a frame with a back wheel and the only way to limit the travel on the high gear side with the cable length. There is a working limiter screw for the low gears and a screw for the high gears but no tab for the high gear.

I might try to ride it tomorrow if I time to assemble the bike. I may tighten the cable enough that it can't go into the 13, until after it stretches.

Gonna be interesting.

Is it like this one on Flickr? He says it's a NOS 1988-1991 model. It's worth seeing the photos, I can't link them here.

That one has the same high and low stop method that my 2005 Veloce uses.

The left screw, low gear/big cog, hits the end plate at the red arrow. The high gear/small cog screw is similar, hidden behind the cable clamp at the green arrow. Is yours different?

http://lh3.googleusercontent.com/_wc...e%20limits.JPG

Yes, this Chorus derailleur is a NOS 1988 - 1991 model, photographs attached. This derailleur along with it's fellow Croce D'Aune model of the same era are things of beauty.

http://farm4.static.flickr.com/3496/...3b1568710d.jpg

http://farm3.static.flickr.com/2446/...c78c45bc2c.jpg

http://farm4.static.flickr.com/3534/...15ba63d0c9.jpg

The Campagnolo Chorus rear derailleur allowed versatility, especially for a bicycle whose specifications lend it toward a wide range of users, is an indispensable characteristic.

A bicycle for professional racing can if fact be used for competition, touring, triathlons and non-competitive cycling.

The Campagnolo Chorus derailleur was designed with the 'Dual Mode' system. The Dual Mode system allowed the derailleurs parallelogram to be rotated in different working positions at 5 degrees and 30 degrees.
Max Cog:- A position 27 teeth, B position 32 teeth.

It doesn't have the A-B settings. When I bought it at a swap meet, the seller said mid 1990s. My other Chorus, one I bought new in the late 90s or 2000 has both stops so I can only conclude that there was a run without the high gear stop.

Being semi retired, or semi ******** as I sometimes say, I had time to ride it a couple of miles, and then relaxed the cable to get into the high gear and, it still shifts OK. It looks like cable length is the only stop.

I'll report back when it has a few more miles.

It's on a nice steel frame of indeterminate vintage, brush painted with filed lugs a mountain biker friend picked up at a garage sale. It had no derailleurs, rusty chain, OK wheels, Tipo hubs, steel freewheel and Weinmann brakes I replaced the chain and cables, added an old Sun Tour front derailleur and if it shifts OK after a few more miles, will turn it over to him for a road bike with a warning to him to watch the cable length, and, maybe avoid the 13 tooth cog.

A few weeks have gone by, the bike bike has about 100 miles on it and I tightened the derailleur cable ever so slightly.

Shifting is fine.