Campagnolo Chorus 12 Speed "Sub-Compact"--Jaegher Test Mule

[jamesdak]

Originally Posted by Tim Porter

Nick, that was my reaction, too. jamesdak you are one quick dude!

Nah, I think it's this bike and the cassette maybe. Other bikes setup with 50/34s work better for me.

[gfk_velo]

Originally Posted by Tim Porter

Thanks all.

Some tech factoids:

1. If you want to go this route, be sure to consider whether the smaller chainrings will be compatible with whatever FD mount you may have. The Jaegher has a brazed on fitting and I had to . . . modify it a bit with a file (a few mm) in order for the FD not to be too high above the chainrings. I seem to have gotten it just right because the FD shifts very well. I need to futz around with the fine tuning a bit more, but that's pretty normal. The 12 speed FDs operate a bit differently from the 11 speed FDs, btw, with the ability to trim the FD inward with one click when you're in the bigger cogs in back, and I don't have that down perfectly yet. If you have a band around the seat tube for your FD you'd be golden.

2. Chain length on the mechanical 12 speed for Record and Super Record is governed by chain stay length. Neither Record nor SR have the 48/32 combo, however, and it may come out that you need to shorten a new chain by another link in order for the RD to have enough tension. They do not mention any of this yet in Campy's manuals, btw, so I'm flying a little blind and using the R and SR chain length. But in the small/small combination the RD it's seemingly impossible to get the RD adjusted so that the cage very slightly points down, i.e., with the rear idler wheel lower than the top one. I may be missing something so will be fine tuning this.

More to come, I'm sure. Tim

The chain lenght rules are (in theory) the same for the 32 inner - they key is to use the "B-Screw" no ensure that the very short run of chain from the 11 cog to the guide pulley doesn't run "uphill" - rather than using the relative heights of the two jockey wheels as your guide.

The derailleur cage should be as close to the 11 as possible whilst not "over-wrapping" the chain around the 11, and allowing enough clearance that the cage does not foul on the next-biggest sprocket as each shift onto the next biggest sprocket is undertaken or as each shift from a bigger sprocket to a smaller one is taken.

There are some odd differences that crop up when the gear hanger, chainstay length or BB drop are very close to the margins set ny Campagnolo in the technical manual.

FD setting - if you use the UT-FD220 tool (the 50T tool works on 48T adequately) to set the FD height, the following set-up routine will give you the correct FD setting. It's the method by which we set up all the team bikes that run mechanical and the technique we teach Campag ProShop mechanics:

1. Fit the chain around the small chainring (as you would for any other FD installation) and adjust the rear derailleur so that you can access all the sprockets correctly at the rear.
2. With the gear cable not attached to the FD, unscrew both limit screws all the way so that the inner lmit screw is not limiting inner movement at all.
3. With the FD cable adjuster screwed to it's minimum length and the LH lever set in lowest-gear position, pull the front gear cable pretty much as tight as you comfortably can and secure correctly at the pinch bolt - pay attention to the small shoulder that the cable has to pass over.
4. With the chain on the biggest sprocket at the rear use the cable adjuster to incresae the front gear cable tension until you have a 0.5mm gap between the outside surface of the inner cage plate and the back of the chain. Turn the pedals and adjust until there is no chain rub but the chain is passing as close to the inner cage plare as possible.
5. Screw the inner limit screw in until it "just" contacts the limit surface.
6. Take one full sweep (3 clicks) on the LH gear lever whilst turning the pedals to bring the chain to the outer chainring. Do this with care as it is possible at this point to over-shift.
7. Derail to the smallest sprocket at the rear.
8. Screw the outer limit screw in, until there is 0.5mm between the inner surface of the outer cage plate of the FD and the outer surface of the chain. Turn the pedals and check for chain rub. Slightly adjust the outer limit screw if needed.
9. Take the chain to the biggest sprocket at the rear and check that one "click" on the LH thumb lever trims the FD in far enough that there is no chain scrape - on relatively long rear triangles (420mm plus) you may not need this trim position but leave the gear cable tension where it is, anyway.
10. Drop to the inner ring with one further click on the thumb lever and take the chain at the rear to the point where it no longer rubs the FD. In most systems that is around sprocket 7, counting from the smallest towards the biggest. If the chain still rubs here, let a small amount of tension out of the FD cable until the rub is eliminated.
11. If you made an adjustment in step 10, Recheck the big ring-small sprocket combo to make sure you still have no chain rub.

That all sounds more complicated than it is ... it's pretty quick to do and should give you a perfect FD set up. Bear in mind that with the very high cable tension, you may get some seating of the cable outer and "squirm" under the bar tape, so some small tweaks may be required after a couple of hundred km and several shifts. We tape the gear cables with insulation tape from lever to ferrule, before taping over with bar tape, to lessen the tendency for the outer to squirm. We also grind the outer cable ends flat after cutting, opening the liner out with a pick afterwards.

[Tim Porter]

gfk velo, thanks so much for taking the time to set all of that out! I'm away from that bike for a week or so but will do all this when I get home. T

[sailorboy]

OP you had me at 'ecumenical' but thanks for this review and all others adding on. Great info and this kind of setup looks like its in my future somewhere.

[Tim Porter]

Originally Posted by sailorboy

OP you had me at 'ecumenical' but thanks for this review and all others adding on. Great info and this kind of setup looks like its in my future somewhere.

Thanks, sailorboy! I give it my best shot, word-wise! TLP

[oldpotatoe]

3. With the FD cable adjuster screwed to it's minimum length and the LH lever set in lowest-gear position, pull the front gear cable pretty much as tight as you comfortably can and secure correctly at the pinch bolt - pay attention to the small shoulder that the cable has to pass over.

Probably being way presumptuous but I adjust inner limit, when in small ring and biggest cog(lowest gear)..so chain just tickles the FD inner plate, THEN attach cable TIGHT, then turn inner limit screw out a wee bit..you get that .5mm clearance plus the front der cable gets tighter..makes for no need for those daffy inline cable adjusters.

Then big ring, smallest cog(highest gear) and the outer limit screw just touching the limit..not cranked down..then you'll get the '3clicks, to big ring'..

[Dave]

Originally Posted by oldpotatoe

Probably being way presumptuous but I adjust inner limit, when in small ring and biggest cog(lowest gear)..so chain just tickles the FD inner plate, THEN attach cable TIGHT, then turn inner limit screw out a wee bit..you get that .5mm clearance plus the front der cable gets tighter..makes for no need for those daffy inline cable adjusters.

Then big ring, smallest cog(highest gear) and the outer limit screw just touching the limit..not cranked down..then you'll get the '3clicks, to big ring'..

I've done the same until this latest generation of FDs. I finally gave in and used the Campy provided inline cable adjuster on my new frame that has no tension adjuster. My old bike has an adjuster on the frame, so it works fine.

I haven't found the Campy tool to be necessary. Just set the height over the tallest teeth on the crank and eyeball the cage to be parallel to the big ring.

[NoMoreParagon]

Originally Posted by Tim Porter

Thanks all.

Some tech factoids:

1. If you want to go this route, be sure to consider whether the smaller chainrings will be compatible with whatever FD mount you may have. The Jaegher has a brazed on fitting and I had to . . . modify it a bit with a file (a few mm) in order for the FD not to be too high above the chainrings. I seem to have gotten it just right because the FD shifts very well. I need to futz around with the fine tuning a bit more, but that's pretty normal. The 12 speed FDs operate a bit differently from the 11 speed FDs, btw, with the ability to trim the FD inward with one click when you're in the bigger cogs in back, and I don't have that down perfectly yet. If you have a band around the seat tube for your FD you'd be golden.

2. Chain length on the mechanical 12 speed for Record and Super Record is governed by chain stay length. Neither Record nor SR have the 48/32 combo, however, and it may come out that you need to shorten a new chain by another link in order for the RD to have enough tension. They do not mention any of this yet in Campy's manuals, btw, so I'm flying a little blind and using the R and SR chain length. But in the small/small combination the RD it's seemingly impossible to get the RD adjusted so that the cage very slightly points down, i.e., with the rear idler wheel lower than the top one. I may be missing something so will be fine tuning this.

More to come, I'm sure. Tim

Tim once again thank you for the very informative post. I am thinking on how my new gravel setup will be. I been a Campy guy all my life but had to go to Sram for my current ride as Campy was simply not there with bike design development. This new Chorus is very promising. I have a question for you for which you might or might not have an answer. Do you think a 11-36 cassette would fit? Is the spacing between cogs similar to Sram or Shimano 12 speed? a 48/32 front chainrings coupled with 11-36 will really make the setup suitable for the gnarliest gravel.
thank you

[Tim Porter]

NoMoreParagon: An 11-36 would be a new frontier for me so I have not yet even thought about trying that. I'm waiting for the supplemental cogs to arrive from Campy that'll give me a 34, for which the system is designed. My experience with Shimano indicates that you can often squeeze in a couple more teeth on the largest cassette cog, but I'll have to defer to gfk_velo or Dave or Old Potato to see if their experience has lead to any conclusions in that regard.

I do know that Campy does not yet make a cassette with a 36, so it's automatically going to be a kludge, of course.

[Dave]

The other brands don't offer a 12 speed cassette with a 36T sprocket that would fit on a road bike. Shimano's are MTB only and SRAM only goes up to a 33.

If lower gearing is needed, a 46/30 crank would be a better option.

I haven't read anything about cog spacing, but SRAM's AXS chain is by far the narrowest at 5.02mm.