Barrettscv 

Is a Campagnolo 10 speed rear derailleur compatible with late generation 9 speed Ergo levers and a a 9 speed cassette?

I found this wiki, but I'm still not precisely clear as to what's compatible: https://en.wikibooks.org/wiki/Bicycl...ing_Dimensions

Does Veloce, Chorus and Record all have the same pull ratio?

RiddleOfSteel

Pointy top Ergo levers: old pull ratio - As we know, many of these were 8-speed, with the final couple of years being 9-speed between various levels.

RD with B-tension screw in the 'normal' location (at the anchorbolt/RD frame dropout): old pull ratio

Round top Ergo levers: new pull ratio - 9- and 10-speed only

RD with B-tension screw at the upper jockey wheel/pulley: new pull ratio

All old-ratio shifters work with all old-ratio RDs, and all new-ratio shifters work with all new-ratio RDs.

Campagnolo kept the same RD pull ratio going into 11-speed, so you can use the sculpted top 11-speed Ergos, presumably, with a 9/10 speed new-ratio RD.

Barrettscv 

I can assume that these are the round top version 9 speed Ergo lever that will work with a 10 speed rear derailleur, yes?

nesteel 

Those chorus shifters are considered "late" 9, which should work with 10.
Personally, the entire "early" and "late" 9 speed issue is largely overblown. I've mixed and match with no issues in the past. I'm currently using a late 9 RD with converted 10speed shifters/cassette. Works fine.

RiddleOfSteel

Yes that shifter is the 'round top' referred to.

Choke 

Oldpotatoe, former owner of Vecchio's in Boulder and one of the foremost Campy gurus, had this to say on another forum: "I use 2010 Campagnolo rear derailleurs(10s) as replacement rear derailleurs for all Campagnolo shifting systems from the late 80s thru present. The 'pre/post 2001' stuff in actual practice means nada".

gfk_velo

Well, Campag didn't fully re-tool just for the fun of it. In fact, that "nada" depends on a lot of factors.

There is a small difference in pre / post 2000 cable recovery. It's roughly 0.6mm of cable across the full RD travel, translating to a little over over 1mm of derailleur movement

When the kit is old and a bit sloppy, that can play out one of two ways - either the shifting is "acceptable" but lever movements are larger than they should be, or it just doesn't work in any way that most would regard as acceptable, especially when users start to introduce other chains, cable systems, third party cassettes etc. It really depends what the user is happy with..

Conversely, when everything is brand spanking new, the index tends to be slightly "off" at the top and bottom of the cassette, if it's optimised on the middle sprocket (which is what Campag recommend). This varies from big to small chainring as well, as a result of the chain being "pulled" towards the centre-small side when on the big chainring by chain tension and centre-big side on the small ring. The shorter the rear triangle of the bike, the worse the effect. The wider the cassette range, the worse the effect.

To iron out these problems, was the reason that Campagnolo went to the trouble of re-designing the cable bushing slightly and re-tooled accordingly, then made the recommendations with regard to maintaining compatibility - much the same scenario as pre / post 2015 RDs / levers in 11s.

Then ... not all 10s RDs impart the same cable tension as one another and that can have an effect on mech / lever compatibility.

Rounded top, full Ergopower levers (and through a slightly different mechanism, UltrShift levers) have a deliberate "overshift" built in, when shifting from the smaller sprockets to the bigger - this is achieved, in rounded top ErgoPower levers, by the spring carrier being able to rotate slightly (around 5 degrees) inside the shifter body, so that as you move from a smaller sprocket to a bigger one, the lever action moves the cable bushing however many clicks but also rotates the whole cable bushing / index spring / index spring carrier assembly slightly further than a correct index point. When the lever is released, the tension on the gear cable should pull that assembly back to the correct index point (provided cable tension is right).

RDs that are designed for use with Escape type levers, or with PowerShift levers, generate around 100g less cable tension than those designed for "full ErgoPower" and UltraShift levers. They can struggle to pull the shifting assembly back to the correct index position. Either it doesn't go at all, or it "settles" back after a second, or a few seconds, due to road vibration etc helping it move. To compound matters, some round-top Full ErgoPower levers have higher internal resistance to that rotation of the internal mechanism than others, as the low range levers have a brass bushing for the internals to rotate inside, rather than a pair of sealed bearings as are used on the higher range levers. Very early 10s UltraShift levers (Veloce and Centaur late 2008, early 2009) used a plastic bushing and were even less satisfactory in that respect .. the internal resistance of the lever to "return motion" was high enough that you could get good indexing "up" or "down" but in many cases, not both, on both rings.

As a generality (and there are examples where it isn't necessarily the case, I run one myself, in fact), you should use Record or Chorus 9 or 10s of any age, Centaur (Daytona) or Veloce pre-2006, Xenon and Mirage pre-2002 with UltraShift 10s or Full ErgoPower 9 or 10s to get completely predictable set up and long-lasting adjustment. These RDs all create, at the lever, 1kg plus of "backward" pull on the gear cable.Other 9 and 10s RDs only create around 900g of backward pull and that can either cause very "picky" set-up, or the aforementioned inability to get good indexing in both directions, on both chainrings.

Cable runs also have a lot to do with it. I am running UltraShift with a Centaur RD for PowerShift (so a definitely sub-optimal combination) on one of my bikes but the cable runs are simple, clean - and once at the frame - external, so it works OK, so long as I keep everything fairly pristine and don't push my luck with (especially rear section of outer) cable life.That would probably not be the case with a more convoluted cable run / tight bends at the 'bars as one often ends up with on "compact" type bars etc.

Just to *really* complicate matters, Campag made "special" Veloce and Centaur RDs in late 2009 and 2010 which reverted to the stronger spring.
At the same time, they changed the Veloce and Centaur UltraShifts too, giving them a cartridge bearing system internally which, allied to other changes to the clutch and cable bushing that were shared with Athena, Chorus, Record and Super Record 11s, made the shifting very crisp and accurate.