Originally Posted by
Drew Eckhardt
Some Campagnolo derailleurs have two positions for the lower pivot spring so you can have more adjustment range than the tension screw provides.
Chorus/Record attach the pivot with a bolt you can't lose like the lower gruppo clip.
I'd disassemble it and see if that's the case.
No idea if they ever did the same thing with the upper pivot - I never had to mess with one.
Otherwise don't exceed Campagnolo's derailleur limits.
10 speed official derailleur capacity limits were:
Short - 55mm between pulley bolt centers. Officially for standard/compact doubles and all cogs but 13-29. 27T wrap. Or 30T of wrap (2010 OEM manual). 26T (2010 OEM manual) or 27T largest cog. 16 minimum to maximum sprocket difference (which the observant reader will note might get to 13 + 16 = 29 if you don't run out of wrap first, perhaps in situations like 50-39 rings not on Campagnolo's menu)
Medium - 72.5mm between pulley bolt centers. Officially for standard/compact doubles and all cogs plus triple cranks with all cogs but 13-29. 30T wrap. Or 32T of wrap (2010 OEM manual). 29T largest cog. 16 minimum to maximum sprocket difference.
Long - 89mm between pulley bolt centers. Officially for triple cranks and all cogs. 38 (2010 OEM manual) or 39T wrap. 29T largest cog. 22 minimum to maximum sprocket difference. Obviously with the specified 11 minimum starting cog and a 22 range you'd end up with a 33 large which is beyond 29T.
The 8/9 speed Racing-T derailleur was a medium which I measured at 75mm between jockey wheel axles.
Personally, I'd pair a smaller cassette with a triple crank and NOS 2006 Record Titanium derailleurs. You can have one tooth jumps to the 19 cog, more speed before shifting to your big ring, and a lower gear for mountains. Chorus 10 speed ergo levers will all run a triple using 6 or 7 out of 12 positions.
So this is saying that 50/34 with 13-29 just won't work on my setup if I tried, and that Rosefarts 12-30 would be even worse. But reality is more like it kinda/sorta works, with maybe some rub somewhere or a little chain slack in the small/small. Hmmm, as long as it will shift onto the 29 and still work I may consider this yet again. I can say that I never ride the small/small combo, I much prefer to be on the big ring in that range of gears, but I do ride the big/big on my current combo when I hit a small hill that doesn't require going onto the small ring. If I lived somewhere with real hills I'm sure I'd have a different style of riding, but it is what it is here. PBK has the 13/29 Veloce available.