Campy 11 cable pulls

[Dave]

I have measured the cable pull on my 2018 Chorus shifter and found a significant difference in the total cable pull, compared to the 2014 and older models. I consistently came up with a total pull of 31mm, compared to 28.5mm for the early model shifter. The first pull was 4mm. Pulls 2 and 3 were both 3mm, while pulls 4 and 5 were only 2.5mm. Pulls 6,7 and 8 were all 3mm. Pulls 9 and 10 were 3.5mm. I did have to use a different measuring technique, since my bike has internal cable routing and no exposed cable below the chainstay. I disconnected the cable from the RD and measured from the ferrule where the cable exits the frame. Tension was applied by pulling on the cable, by hand.

To compare the older shifters properly, I took measurements of cable pull, using the same technique, with the cable disconnected from the RD and tension applied by hand. I got the same 4mm pull for the first shift, instead of the 3mm when connected to the RD, which showed that the limit screw was affecting the pull measurement. The next 6 pulls were all 2.5mm. Pulls 8 and 9 were both 3mm and the last pull was 3.5mm, with a total pull of 28.5mm.

The difference is about 9% and shows why a new RD connected to older shifters, needs some help to produce enough RD travel. Mating new shifters with an old RD will create some over-travel, but maybe both limit screws can be used to reduce some of the over-travel.

[Ralph]

http://www.velotech-cycling.ltd.uk/campagnolo_faq.shtml#comp-mec

Some of that is discussed by this UK Campy pro shop. Scroll down a ways.

[dddd]

I just got through installing a new Chorus HO derailer on a pre-2015 Super Record bike, and I have to say that the travel across the cassette apeared to remain the same.
I even eyeballed the gap between the chain and the next-larger cog that the chain was on in every gear. The gaps did not approach even 1mm difference and to me seemed not to differ at all.

I did suffer some mid-cassette error that had me trying compromosed cable adjustments to the tune of perhaps a half-turn of the barrel, and eventually resolved that with a very slight alteration to the cable's path (a cable's thickness at most).

The difference between 31mm of cable pull and 28.5mm is all of 2.5mm, and which is amplified about 50% by the derailer's actuation ratio for a net difference of say 3.75mm at the pulley.
But I saw essentially zero.

Makes me wonder, how many versions of Record-11 shifters are there?

And can it make sense that there would be such step-wise groups of shifter throw dimension instead of a smooth progression?

I'm just not understanding how a parallelogram mechanism could convert such stepped cable travel progression into an evenly-spaced cassette's cog positions. Without a secondary mechanism involved, I would argue that it can't, and would have to see the data showing measurement resolution far above 0.5mm, which I suggest would be more of a continuous curve than any sort of steps involving pairs or triplets of cogs.

I've seen these stepped travel figures quoted on the Art's Cyclery Blog, where I had initially assumed that someone had perhaps measured the cog spacers in a Campag cassette, which are in fact of varying thickness despite the cog's being evenly spaced.
So I have to ask the OP here, are you perhaps the one whose data has been used in the Art's Cyclery Blog linked below (4th paragraph down)?

http://blog.artscyclery.com/science-behind-the-magic/science-behind-the-magic-drivetrain-compatibility/

[Dave]

FWIW, I've taken this type of measurement many times over the years and I worked as a machinist for many years, so I know precision measurement. Campy RDs have always worked this way, with groups of cable pulls, all the same. I'm working on hooking up a dial indicator setup for measuring the pulls. A metric indicator reads in .01mm increments, but to get enough travel, you need a 50mm or 2 inch travel model.

If you take readings with a precision machinists rule, you'll find that the total travel is always very consistent. Even with a precision dial indicator, it makes no difference if 5 pulls that add up to 15mm are exactly the same, or whether each one differs by .1mm. That info has no real value. What you want to know is how far off you are after many pulls. The error accumulates and gets worse with every shift if the RD's actuation ratio doesn't match the cable pull.

When I take thes measurments, I have no preconceived idea of what each cable pull should be. I just make one pull at a time and write down the total distance traveled by my marker on the cable. I repeat the process several times to be sure that the measurements are repeatable. When all the measurements are recorded, the amount of increase per pull is then figured. The total pull always repeated quite accurately with both shifters.

In this case, when I tried to operate a new potenza RD with 2009 shifters, the RD wouldn't even make the largest cog shift and it's obvious why. I needed 31mm of pull and only 28.5 was available. That's not even close. My old trick of grinding down the cable clamp screw to the root of the threads shortened the effective lever arm length and increased the travel enough to make that last shift and improved the other shifts too. The same mod works to use a 10 speed RD work with old 11 speed shifters.

The spacers on a Campy cassette are all the same 2.2mm and the cog spacing is the same between all cogs.

Posting average cable pulls is really of little value, since none of the pulls is really average.

[dddd]

I hadn't considered the pull requirements of the Potenza derailer at all, since I worked only with Chorus/Record, and since your post didn't mention Potenza.

And I didn't measure cable pull at all.

I'm just stuck on trying to understand why the cable travel would change in steps between groups of 2-3 shift points, and how this could possibly be translated into even gaps between cogs by a simple parallelogram.

Again though, if we were to see more-exact numbers, in a list format of the ten shifts from 1-11, I believe that a stepless curve could be plotted with this data.

[Dave]

I hadn't considered the pull requirements of the Potenza derailer at all, since I worked only with Chorus/Record, and since your post didn't mention Potenza.

And I didn't measure cable pull at all.

I'm just stuck on trying to understand why the cable travel would change in steps between groups of 2-3 shift points, and how this could possibly be translated into even gaps between cogs by a simple parallelogram.

Again though, if we were to see more-exact numbers, in a list format of the ten shifts from 1-11, I believe that a stepless curve could be plotted with this data.

The Potenza RD had nothing to do with checking the cable pull. I just wanted to verify what I already knew, which was that the old shifters don't pull enough cable to properly operate 2015+ RDs. I haven't read of any other change to the shifters. 2009-2014 should all be the same.

If you really want to judge a RD's positioning, take the chain off and see how far off the RD pulley's are after each shift. I first did this in 2009 when 11 speed came out and I wanted to see how much difference there was between a 10 speed RD and the new 11 speed. I found the pulleys to be positioned about half way between the 10th and 11 th cog, after all 10 shifts - obviously short of the needed travel.

[dddd]

Your last point raises the question for me of whether the 10s rear derailer that you tested is the same geometry-wise (i.e. in terms of actuation ratio) as the pre-2015 Record-class derailers.

If it is the same, then I am confused as to why I could not visually detect any difference in actuation using 2014 Super Record shifters with a 2018 Chorus HO rear derailer on an 11s cassette.
I checked with the chain in place to be able to actually shift through the range, and the very small clearance between the chain and the next-larger cog did not appear to vary by more than a half-millimeter from one end of the cassette to the other.

I'm actually now wondering (based on the data you've reported here) if the Super Record shifters I tested with might have been newer (2015+) ones somehow having been fitted with the older style hoods having no side texturing, since I am sure that the deviation from perfect indexing was less than one millimeter at all times.
The shifters in question left my shop this afternoon, so I can't measure anything now, but if there is any other visual cue as to the exact model year I will be seeing this one out on the road and can check.

[Ralph]

Based on the data I posted above....I believe the last 10's Ultra shift levers (the Centaur's with new style hoods) will work with Athena 11's RD's on an otherwise 10's system. And I assume the reverse w/b true also. I assume the early Athena shifters will work with last Veloce RD. But less sure about earlier 10's Chorus and Record RD's.

But I don't assume much other 100% compatibility. As we are learning now....Power shift seems to have been designed to work with power shift parts, and there were running changes year to year with all the systems.

The last Centaur 10's cassettes, the 12-27 and 12-30.....all had 2.5 MM spacers between cogs. Earlier 10's cassettes had a mixture of at least 3 different width spacers....depending on whether or not some cogs on carrier, or were all loose. So something changed there. And we know about the 2015 11's changes.

That's not saying you can't make about anything sorta work together.

[oldpotatoe]

Your last point raises the question for me of whether the 10s rear derailer that you tested is the same geometry-wise (i.e. in terms of actuation ratio) as the pre-2015 Record-class derailers.

If it is the same, then I am confused as to why I could not visually detect any difference in actuation using 2014 Super Record shifters with a 2018 Chorus HO rear derailer on an 11s cassette.
I checked with the chain in place to be able to actually shift through the range, and the very small clearance between the chain and the next-larger cog did not appear to vary by more than a half-millimeter from one end of the cassette to the other.

I'm actually now wondering (based on the data you've reported here) if the Super Record shifters I tested with might have been newer (2015+) ones somehow having been fitted with the older style hoods having no side texturing, since I am sure that the deviation from perfect indexing was less than one millimeter at all times.
The shifters in question left my shop this afternoon, so I can't measure anything now, but if there is any other visual cue as to the exact model year I will be seeing this one out on the road and can check.

A quick way is to look at the back..2015+ take up spools are white, 2014-2010 are black.

Left-2010 Centaur US, middle 2014 SR/Record, right, 2015 SR/Record.

[Dave]

I built a cable pull measuring fixture that includes a 2-inch travel dial indicator with .001-inch graduations. The shift cable is unclamped from the RD and connected directly to a spring tensioned slide on the fixture. A cable tension adjuster is included, to be sure that there is no slack in the cable and any movement of the finger lever starts the dial indicator moving. This device allows very small differences in each cable pull to be measured. One thing that it proved is that the cable pulls do not increase with each shift, as the RD travels from smaller to larger cogs. Both the original model and the new model include a large first cable pull and both have a significant amount of overtravel on the first shift, that returns after the finger lever is released. Both have some excess travel available on the last cable pull that shifts to the largest cog. That excess pull returns, as soon as the finger lever is released.

I made at least five runs through all 10 shifts on both models, to determine repeatability and get the best average value for each shift. Most shifts repeated with a total deviation of no more than .004 inch or .1mm. For reference, a piece of notebook paper measures about .003 inch thick.

Total travel was 27.3mm for the 2009 shifters and 29.8mm for the 2015+ shifters. That’s a difference of 2.5mm. If measurements are taken from the exposed cable on a bike, using a machinist’s rule, the first shift pull is likely to be less, since the limit screw affects the total pull and so does the initial cable tension. My measurements all began from a zero point, with the slide resting on a fixed stop. Below are the cable pulls, in millimeters.

2009 ultrashift 2015+ ultrashift
3.35 -------- 4.0
2.5 -------- 2.8
2.5 -------- 2.5
2.2 -------- 2.7
2.2 -------- 2.7
2.6 -------- 2.7
2.6 -------- 2.7
2.9 -------- 3.0
2.9 -------- 3.4
3.5 -------- 3.4