Does anyone happen to know how many millimeters of cable Campy Ergo 9's pull per click?

In a distantly related matter, I've heard that Shimano rear derailleurs have a mechanical advantage of 1.67 to 1. Can anyone verify if this is true or not?

The reason for these 2 questions is I'm trying to see if Campy Ergo 9's, combined with a Shimano rear derailleur will shift my 7-speed HG freewheel smoothly, or if I need to go with Ergo 8's and a Campy rder? Thanks!!

The thickness of the gears and the spacing on the 7spd SH FW is wider than on the 9spd so in most likelyhood it would not shift the 7 spd. By the same token, Campy ERGO 8 shifters would not work on the 7spd either. It's my belief that Campy and Shimano make their parts different so they can not be interchanged. Some after market companies like Wheels Mfg make spacer kits to overcome this difficulty but I don't think they make anything to convert Shimano 7spd to be compatible with Ergo 8spd. you can e-mail them at www.wheelsmfg.com They are usually good about replying.

L J is correct, a campy 9sp shifter won't even ****ion correctly with a shimano 9sp cassette and a shimano 9sp derailleur. Shimano and Campy parts are pretty much incompatible with each other, with a few exceptions.

I know the cog center to cog center spacing on my Shimano 7-speed HG FW is 5.0 mm. I've heard Campy 8 spacing is 5.05mm. Is this info errant?

If it really is so, wouldn't Campy Ergo 8 with a Campy rder be compatible with Shimano HG 7? Or is there another factor I'm missing?

Thanks!!

Here is info on the 8sp cassette.

Campagnolo 8 speed cassette cogs technical information:
Each cog is 1.9 mm thick. Campy uses 3.1 mm black resin spacers and spaces their cogs 5 mm on center. That is to say that the distance from the center of one cog to the center of the adjoining cog, measured from the center of the first cog to the center of the second cog, is 5 mm.

I did a search and found the spacing C-C of a 7sp is 5mm so you might get it to work just set the limit screws so it does not use the 8th position. I doubt anyone can make any guarntees on this but if you can find 8sp shifters cheap might be worth a shot. Since they are not made anymore if you had to spend money on 9/10sp ones and convert them, might as well just convert to 9/10sp.

9sp is 4.55 so I really doubt it would work smoothly, her eis a link to sheldon's web site with the spacing info.
https://www.sheldonbrown.org/gloss_sp-ss.html

Is there is a reason you want to do this? your 7sp shifters die?

Check out Lennard Zinn's tech talk on Velonews.com

He has addressed this issue quite a bit over the past several months and has additional info archived on his own website. I was quite surprised about the high level of compatibility between Campy and Shimano. In a couple of his responses there are letters from folks at both companies with info on compatibility.