Campy Derailleur issues.....
 

I have a 12 year old bike with Campy Chorus 8 speed derailleur. It broke this morning!! GRRRR.....

The 8/9 speeds are nearly impossible to find. Will the new 10 speed derailleur work with my gear cluster. I mean the indexing is done with the shifter anyway so could that work using the set limiting screws?? Running out of options here.

Thanks all.

The answer is no. All 8 sp and pre 2000 sp had a different actuation ratio on the rear derailleur. Post 2000 9 sp and all 10 sp can be made to work with Jtek #1. Call them up and ask how. It's an undocumented fix. Good luck

OK I'll show my ignorance. What is Jtek#1?? Who do I call?

Jtek Engineering makes an item called the Shiftmate that allows you to run incompatible components with each other. they are basically eccentric pulleys that change the cable pull between the shifter and the derailleur. they make several different models, depending on the application.

According to Campagnolo a 2001 and newer 9 speed mechanism will work with an 8s ergo lever provided that you use a narrower chain (but not a 2000 and older 9 speed lever). Since 10 speed (except 2011 and newer double derailleurs which seem to use the 11 speed ratio) and 2001+ 9 speed share the same ratio you'd expect that to work too although you might run into issues with the narrower jockey wheels if not using a 10s chain.

The floating upper pulley provides some tolerance and I'd guess that it's good enough with the wider 8 speed spacing.

A simple way to avoid the necessity for a thinner chain is to just use some thin washers either side of the jockey wheels.

you wont believe this but i am south east of des moines and recently sold an 8spd chorus derailleur that was in like new condition. ive still got some 8 campagnolo parts (triple derailleur set, triple crankset, bb, and wheelset)

The answer is yes, if you buy a Jtek shiftmate model 2 (1.07 ratio) and run is in reducing mode (smaller pulley to the derailleur).

The spacing on your cassette is 5.0 mm. The cable pull on your shifters is 3.6 mm. The actuation ratio on the new 10 speed derailleurs is 1.5 : 1 so you need to reduce that by 7% to get 3.6 * 1.5 / 1.07 = 5.05 mm which is good enough. Run a 9 speed chain it will work OK on the derailleur.

I used to run this system in reverse (10 speed shifters with 8 speed Record derailleur) and it works OK - a bit of clatter in the outer gears but no skips.

I say just use your existing chain if it's still good and just shim the cage for clearance.

Maybe try a 9spd one when it needs replacing.

If you're staying with 8s you'll probably be able to get by with a new (2001+) derailleur. I was Campy's east coast service tech at the time 10s came out and the RD platform changed (new ones don't have a "B" screw on top). They brought out a new version of the 9s cam for ergolevers, but opted not to mane a new 8s version. Their reasoning was that the difference in geometry was small and while it would affect 9s shifting, 8s was coarse enough to get by with the older cams.

I serviced a number of warranties in that era, sending new geometry 9s derailleurs to replace dead 8s ones, and nobody needed to recam the levers. If you can find an old derailleur that would be best, but if not a 9s or 10s derailleur combined with a 9s chain will work fine.

I have one bike with an old style 9 sp rear der. I'm using 9 sp barcons, which only came in the new style 9 sp ratio. Shifting is OK but not great. My 10 sp is perfect. I'm trying to hunt down a newer 9 sp rear to make it work. Short of that I'll just convert to 10 sp.

10s and 9s derailleurs are identical except for cage width. Buy a 10s derailleur and you'll be fine, even running 9s chains. If you're concerned about cage width (though you needn't be) I have 2 new in box 2002 9s Record derailleurs (carbon body, aluminum cage). PM me if interested.

Thanks all. I've got it fixed! I found out after about 10 calls looking for parts around the country, that when Campy makes the new higher end stuff, they take the old and rename it to the step down. In other words, when the new Chorus comes out, the old becomes the Athena. I found an Athena 8 speed about 100 miles from me (a nice motorcycle ride). It's identical to my Chorus. Like the bike shop mechanic said when I asked him the difference between this and the Chorus, he said about 1 1/2 grams. (He was being facetious....) I lose that much weight getting my hair cut!! For someone that rides a steel bike pulling a BOB, the weight is not an issue! He said that I probably wouldn't really notice a difference. Well, now that I see it, I won't know the difference. There isn't one except the name on the side. My ego can handle that!

So instead of spending $300+ on the new Chorus and another $40 for the adapter, I'm running for $70. That works for me!