My quest for guidance on the Hetchins drive train clearly showed that there is a lot of difference of opinion about which shift levers take up how much cable. So, I did some measurements on the 13 units that were lying in the box.
In the table below, please realize that the "effective diameter" is appproximate: some of these don't wrap around far enough for an accurate measurement, and some don't have their wrap barrels quite symmetrical wrt the axle bolt or nut. Like the Campy BarCon wants to pull more cable per unit of angular change near high gear than near low.
effective diameter of some shift levers
Diameter
Brand
Position
Model or notes
20
Campagnolo
BarCon
biggest at high gear end.
24
Shimano
BarCon
Spring-loaded
23
Suntour
BarCon
Ratchet
16.4
Campagnolo
DT
raised letters
33
Cyclo GB
DT
for plunger derailleur
18
Shimano
DT
DuraAce
20
Shimano
DT
L422 ratchet
21
Shimano
DT
600
15
Simplex
DT
Al, black plastic covers
15
Simplex
DT
Plastic, chrome trim
18
Suntour
DT
ratchet
20
Suntour
DT
Cyclone (2 versions)
19
Suntour
DT
"aero" w curved levers
If your output is garbled, send me an email with this subject and I'll send it as a little xcel file, unless you ask for Word.
Converting from effective diameter to (mm. cable pull)/(degree lever moves) is left as an exercise for the reader. If it gets really dull this winter, I'll set up a jig and measure derailleur (mm moved)/(mm. cable pull), unless someone can find Berto's data. Hint, hint.
What does the effective diameter "data" tell us?
First, Campy ~ Simplex in effective diameter, if nothing else.
Second, the Japanese DT are roughly 25 - 30% bigger than the two European models. Move more cable. True for both DT and BarCon, within brands.
Third, here I thought Suntour was really smart, and used the same ratchet assembly both places. Not true. Really smart in selling lots of both is just as good, though.
I hope this is useful. For example, if you are having trouble hitting your shifts with that Ultra-7 with a Suntour BarCon, drop down a notch in quality and use the Campy -- it works fine on one of my bikes. Conversely, for faster shifts choose a bigger effective diameter.
Or confuse your friends. Put a Simplex DT on the bike with a Crane RD, and brag about the 170 degree shift sector ( guess) . :-(.
Your mileage may vary. If DC locals want me to measure others with my knife-edged Swiss plastic vernier with dial, just bring 'em by. Bigger databases are better.
harvey sachs
mcLean va