Some background... I have been running 7 speed drivetrains for years. Until recently all of my road wheels and my wife's road bike wheels were freewheel 126mm OLD. My wife has used index downtube shifting since the 80's and I have just changed from friction a couple of months ago. My wife got a newer bike with 130mm and I have spread her old steel frame to 130mm.

I have decided to bite the bullet and get some new wheels with DA 7700 hubs. I can squeeze the 130mm into my Cannondale drop outs and I have a couple of ideas to shave a mm or 2 off the OLD on the hubs. I have already discovered the joy of running 38/48 chainrings and a max 32t. Regardless of what I end up with I anticipate going with 8 speeds or 9 speeds max (maybe 8 of 9) cassette. At my age and how I ride, I see no value in 1 tooth cog differences to even entertain going with 10 speed. I will probably go with brifters, but the current choices are: lower end Shimano (or hard to find expensive NOS/decent used), or Campagnolo not as low end (or not as hard to find but not "cheap" decent used).

So here is where this is going...

I understand that published shifter cable pulls are the average pull, i.e.; Shimano 8 is 2.8mm, Shimano 9 is 2.5mm, Campagnolo 10 is 2.8, Campagnolo 11 is 2.6mm. I have also read that Campagnolo shifter pull of 2.8mm is really an average and that the actual pull is 2.5mm (1st-6th), 3.0mm (7th & 8th), 3.5 (9th & 10th).

Is this true? Does Shimano have the a similar variable pull or is it just Campagnolo?

I am asking because I will probably go with a cassette without a spider and gain some grams, but I can make whatever spacing I need whether constant or variable.

Thanks!

John

It would be great if we had a reliable source of data for all of these examples of indexing motion.

It seems like with 10 and 11 speed, fewer people are kluging different brands together as in the past, probably because the narrower spacings are more sensitive to slight differences between brands and to any of the sort of non-linearity that your source implies.

I read in Velo News, one reader reported that Shimano 11 and Campagnolo 11 rear derailers are interchangeable, but to what standards of accuracy was not specified.

I am myself wondering if Campagnolo 10 and 11 speed rear derailers have exactly the same actuation ratio.
In Shimano's case, the actuation ratio was actually changed in the switch from 10 to 11 speed for the road gruppos, decreasing the derailer's actuation ratio toward the Campagnolo specification.

You are right that cog spacers can be altered to compensate for any minor indexing discrepancy. I used to modify Shimano cassettes for use with 7s Accushift Command shifters, to good effect!

I have myself noticed that using the next-narrower width of chain makes indexing discrepancies much less critical in actual use.

7 speed brifters are available if you'd rather avoid the headache.

I actually have a set of Shimano ST2300 brifters that werre on my wife's old road bike that I am converting to a flat bar. Since my road bike is a bike I have cherished for a long time, I really would like to get little higher quality shifters. Most higher end Shimano 8 speed brifters that are available are used and may or may not function very well, or, very expensive NOS for 90's vintage brifters. That is why I think Campagnolo 10 speed may be a better way to go.

John