Derailer / Shifter Math for my Custom

[lconley]

So after several months of inactivity on the assembly of my custom due to being busy on other things (selling house, selling 2 cars, moving, etc.), I am about ready to begin working on it again. I have an 11 speed Dura Ace 12-28 cassette and an 11 speed Campagnolo Athena derailer. I have a bunch of shifters of all sorts, so I wondered if any of them would allow indexing of the mixed components. So my research says: the Shimano cassette has a cog spacing of 3.69 mm. The Campagnolo derailer has a shift ratio of 1.5. Divide the cog spacing by shift ratio to get required cable pull - 3.69 / 1.5 = 2.46. A 9 speed Dura Ace bar end shifter (or Microshift 9 speed - of which I have both) has a cable pull of 2.5 - sounds like it might work if the shifters mount up to the head tube mounted shifter bosses. Both the derailer and the head tube shifter adapters have cable adjusters - so I should be able to select which nine of the 11 cogs I use by adjusting cable tension. The smallest nine give me 31 to 95 gear inches - plenty for Florida, the middle nine give me 28 to 87, the big nine give me 25 to 81 in case I venture into steeper territory (Rene Herse 42-26 crank).  I may just put Silver1s or Silver2s on and friction shift (25 to 95), but I will have to try the indexing just to see if my math is correct (the curse of being a mechanical engineer).

Laing

Delray Beach FL

[John Hawrylak]

Sheldon Brown has an article on Alternate Derailer cable routing (Drivetrain Compatibility?) where he shows attaching the cable on the back or front of the clamp bolt )vs the bottom) to make up for small mismatches.  Dont' know if could help you.  Ran across it looking for 7s cassette info.

John Hawrylak

Woodstown NJ

[aeroperf]

From one ME to another, go for it.  You do the math to get as close as you can, but then the testing takes over.
Also figure that the Hyperglide cassettes do help you out a bit, and if you can pull the chain reasonably close, you may get the shift.
So above your index, you might just be able to get a tenth gear with over-stretch.  I get 8 gears out of 9 on a Sora-equipped road bike using a 7 speed shifter.

[Joe Bernard]

The first thing I would do is try the Campy 11 shifter and derailer with the Shimano 11 cassette. I don't have the cold hard facts in front of me, but anecdotal evidence is the spacing is so close for 11- and 12-speed systems that it'll work just fine.

[William deRosset]

I can report that a SRAM 11s road setup shifts both Shimano 11s cogs and Campagnolo 11s cogs with equal aplomb.

It also shifts the 10s era 53/39 campagnolo Record chainrings, though one must carefully read and follow the Yaw front derailleur setup instructions. This ain't your childhood Nuovo Record, and it isn't entirely intuitive.

Best Regards,

Will
William M deRosset
Fort Collins CO USA

[Joe Bernard]

Hmm, I'm reading again and now I realize you may not have a Campy 11 shifter for that derailer. In that case I'm out of ideas!

[Fullylugged]

If you want to use indexing, use a shiftmate to cross match Shimano and Campy: http://www.jtekengineering.com/shiftmate/

If you go friction, everything works with everything.

[Brewster Fong]

I can confirm that ALL 11 speed systems work together equally. So you can mix and match Campy drivetrain with Shimano/Sram cassettes or visa versa. So if you have a Campy 11 drivetrain, e.g., Campy shifters and derailleurs, you can use a wheel that has Shimano 11 cassette. Just make sure you use an 11 speed chain. I like KMC, but there's Sram, Wipperman and others, especially if you want a master link.

Good Luck!

[Ted Durant]

On Thursday, July 23, 2020 at 4:40:42 PM UTC-5 lconley wrote:

... I have an 11 speed Dura Ace 12-28 cassette and an 11 speed Campagnolo Athena derailer. I have a bunch of shifters of all sorts, so I wondered if any of them would allow indexing of the mixed components. So my research says: the Shimano cassette has a cog spacing of 3.69 mm. The Campagnolo derailer has a shift ratio of 1.5. Divide the cog spacing by shift ratio to get required cable pull - 3.69 / 1.5 = 2.46. A 9 speed Dura Ace bar end shifter (or Microshift 9 speed - of which I have both) has a cable pull of 2.5 - sounds like it might work..

I've put together a spreadsheet of all this info, as much as I could collect from the Web. My info agrees - the rear derailer moves at a ratio of 1.5 : 1, and Shimano 11 Road (not the same as Shimano 11 Mountain) is 3.96mm between cog centers, and that means you need 2.46mm of cable pull per click to make the Campy derailer hit the cogs on the Shimano cassette. My calc for Shimano 9-speed shifters is 2.53mm per click, which is a bit more, but if you're only using 9 of 11 you might find it works quite well. 

Interestingly, the math also works out to ~2.5mm for a SunTour derailer on Shimano 8-speed, so I'm using Shimano 9-speed bar ends with a SunTour XC pro rear derailer and an 8-speed cassette.

I find it more palatable to use only 8 of 9 clicks on a shifter than to use only 9 of 11 cogs on a cassette. Seems like you're carrying extra weight if you don't get to use those two cogs ;-)

Ted Durant

Milwaukee, WI, USA