GRAN PREMIO SHIFTING ISSUES

There was a transmission issue that was driving me nuts.  The Legnano had been built up for test riding purpose only.  That means that it was not important that everything was working perfectly.  The purpose of a test build is to allow the opportunity to ride the bicycle.  Brakes must work.  Everything must be properly tightened up and secured.  But the bicycle does not have to shift perfectly.  The primary purpose of a test build is to help ensure that the structural and geometric integrity of a frame set has not been compromised.

A bent or damaged frame set will show up immediately, in most instances, as soon as the bike begins to roll.  A bent frame or fork set, often times a deal breaker when considering a build, will manifest itself by pulling one way or the other when the bicycle is ridden.  You do NOT want to restore a bicycle, paint art and all, only to find out that the frame or fork set is bent!  I learned this fundamental rule the hard way.  Back to the Legnano.

During the test ride, the bike handled just fine but the transmission proved to be troublesome.  Shifting seemed to drag and hitting the "sweet spot" proved to be a hit and miss (mostly miss) situation whenever the bike changed gears. Additionally, there was an annoying drive clicking or roughness (perhaps an indexing feel), that refused to go away, no matter what I did to adjust the derailleurs.  My guess was the annoying feel was a product of the toothless jockey sprockets fitted to the Gran Sport rear derailleur.  I was bang on the money, but for reasons I did not understand at the time.

Closer inspection suggested that not only were the jockey wheels worn but they also appeared to be out of alignment.  The rear derailleur sticks way out there on a bicycle and is subject to being banged from time to time.  A sufficient jolt will bent the derailleur and or the derailleur hanger.  Either problem will knock the rear derailleur out of alignment.  A mis-aligned rear derailleur will not shift well, nor will it operate smoothly once shifted.

Initial close inspection suggested that something might be bent in the rear derailleur department.  Was it the derailleur itself, a bit of a problem since I did not have a box full of old Campagnolo Gran Sport derailleurs kicking around.  Or, was the derailleur hanger the culprit?  With this question in mind, I removed the rear derailleur and took the time to check and measure the frame set, checking for alignment as I did so.  The results of the inspection suggested that the frame set was just fine.  That meant looking closely at the derailleur was the next task at hand.

Well, the rear derailleur was not bent, but it was in need of some TLC.  As it turns out, the jockey wheels on the Gran Sport chain jumper features ball bearings to facilitate rotation, rather that the simple bushing used on later model jockey wheels.  The bearing adjustment on one of the jockey wheels had shifted, allowing for way to much clearance in the bearing assemble.  This extra clearance allowed the jockey wheel to wander from side to side in the derailleur cage, making it very difficult to hit the correct spot when friction sifting.  Additionally, operation of the drive proved to be very noisy, thanks to the poorly adjusted idler.

Additionally, this extra clearance had allowed a considerable amount of road grime to enter the tiny bearing cavity.  The grease and grit mixture had solidified over the years, resulting in a very rough feel when in operation.  Disassembling and cleaning the jockey wheels was a very simple task.  Assembly was a pretty straight forward issue also, but getting the bearing play adjusted just right took a couple of attempts to get it just right.

With the rear derailleur repaired and lubricated, it was installed again and tested in the work stand.  No issues.  The roughness was gone.  The transmission shifted well but not a nicely as a newer model would have.  That said, the Campy Gran Sport derailleur is Old School and is not to be expected to work as well as more modern equipment would.

With both the drive and transmission working the way as intended, attention was turned to shifter options.  The tried and true down tube shifters would certainly be the easiest way to go.  However, since the seating position on the Legnano was to be more upright that it would be fitted with drop bars, a different means of changing gears seemed in order.  I toyed with the idea of using Barcon shifters and several sets were tucked away in The Old Shed just waiting for an appropriate project.  The worry was, how would I mount the bar end shifters?  The handlebars selected for the Legnano, and the accompanying handle grips did not lend themselves well to Barcon installation.  The handlebar inside bore was just too small.  Some creativity would be in order.

NEXT - THE GRAN PREMIO CONTROLS