Originally Posted by
John E
I found a rare (common in the early 1970s) SunTour 27T cog, so I am going to try the Bianchi with 50-42 / 14-16-18-20-23-27 for 1.5-step normal use and 50-38 crossover with the same freewheel for hillier rides. I'll let you know if I can make the 1980 NR work w/ 27T ... .
John E...
I've posted this info many times before.... This is wandering off topic from Campy Victory gears but here goes... Short Response from the message I posted above with some embroidery:
"Manufacturer's published rear derailleur capacities were conservative CYA numbers that were intended to provide out of the box, Plug and Play performance on most bike setups. They didn't want to have to deal with unhappy customers complaining that such and such derailleur didn't work on their bike... One exception, Suntour competition model RDs from the 1970's "V" through the late 80's RDs maxed out at 24T or 26T PERIOD!
With a little trial and error - changing chain length, wheel position in the dropout and in some cases the "B" adjustment screw on the RD allows at least one if not two FW sizes larger than the published maximum rear sprocket size."
During the 70's we sold more high performance bikes plus high end components than all of the other shops in our region combined ($300 and up during the bike boom - $400-$500 and up later on). Everything from Teledyne, Graftek and early Klein frames to Italian, British and French full Campagnolo factory assembled bikes. The reason I mention this is because most of the better quality bikes and components were sold to commuters, tourists and casual riders who wanted a nice bike rather than to racers (who never had any money).
Before 1975-76 full factory equipped Campagnolo models were set up for racing out of the box with 13 or 14-23T freewheels and 52 or 53-42T chainrings. Most of those models went out of our shop with 14-28T 5 speed "alpine" gearing. Rarely did we ever have a problem setting them up for our customer's needs. 6 speed FWs and 13-28T FWs weren't readily available plus the narrow Suntour Ultra FWs hadn't come out yet.
As far as Campagnolo NR RD capacity, about 10 years ago I was on a Classic Rendezvous ride where there were 2 bikes running 34T FWs and one with a 32T FW using standard Campy NR RDs!
I have 28T FWs on most of my Campy NR equipped bikes plus ran a 13-31T FW on another one
,
The urban myths about the Campy Nuovo Record RD capacity have been circulating for over 50 years!!!
Here's a BF thread from 2 years ago with a copy of Frank Berto's 1984 Bicycling Magazine article listing the results of his RD comparison tests. He also lists advertised sprocket sizes plus real life capacities without making any changes out of the box.
https://www.bikeforums.net/classic-v...ing-berto.html
Check out the comments @
T-Mar added.
Originally Posted by
John E
(Swapping the inner chainring is a variation on an old theme for me. In the 1970s I used to run 50-47 / 14-16-18-20-23 half-step for flat rides and 50-42 / 14-16-18-20-23 for hills. I need some lower ratios today ... .)
Back in 1975 before the days of PCs I spent some time with a Texas Instruments desktop calculator and a pad of graph paper "gear freaking" as Frank Berto called it. What I came up with was a 13-26T 5 speed freewheel and 49-45T chainrings. I had access to just about every Atom/Regina sprocket so I custom built my freewheel. Tke result was true 1/2 step gearing of 5% or 10% increases or decreases between shifts.
I found that a 4 tooth difference between chainring tooth counts worked out the best for all of the 1/2 step combinations that I tried: 52-48T, 51-47T, 50-46T, 49-45T and so on. It gave me ~40" to 101" gearing. I used my 49-45T / 13-26T combo until about 2007 when I discovered that all of the other old guys were running 28T rear sprockets with smaller chainrings.
These days I run 50T, 49T or 48T large chainrings with 38T or 39T small rings with 28T large sprockets. I don't worry about what gear i'm in I just use what feels good.
verktyg
