Wednesday, September 7, 2011

Vintage Cross Bike 2.0

Well I'm already changing the vintage cyclocross. First I have switched out the saddle to a Turbo; I'm really warming up to these old saddles. The main problem I have run into now, is I need lower gears. I will not be competing with this bike, but the fire-roads around here are steep hard-pack so there is a lot of seated grinds for literally miles. Since I am using a Nuovo Gran Sport crankset I am stuck with a 42T CR in front. The Nuovo Gran Sport derailleur pretty much maxes out at 26T; I need bigger. As I mentioned in my previous blog entry, my original cogset was a 6 speed Uniglide with a 24T largest cog; my first thought was to change the 24T to a 26T, but then I ran across a cassette I could use (see below) with a 28T, so I need another derailleur. The next generation derailleurs (Corsa or C-Record) were made for larger cogs. The record takes a 28T, the Chorus with an adjustable b angle and slant parallelogram option takes a 32T (I have one of these but I'd rather not use it) and Athena (which a also have) with an adjustable b angle takes a 30T (the adjustable b angle allows you to position the upper pulley in relation to the largest cog). There is also the same genre sport level Victory derailleur with an adjustable b angle that takes a 30T (this is one of the differences from Triomphe with no b angle adjustment that took a 28T). I've looked at the Rally (Gran Sport long cage) derailleurs but I really don't like the way they work.

The bike is built mainly around Nuovo Record genre including the Triomphe brakes, which are a Gran Sport copy but easier to find in standard length). Speaking of the brakes the Triomphe arrived and have been mounted. I was also surprised to see that one of the brakes (the rear) had a recessed pivot DOOO! Here we have an NOS set of brakes with different style pivots! Well, fortunately I still had the standard set of pivots I bought to convert the Gran Sport brakes before I determined the arms were too short. Even though I only needed to change one pivot, I switched out both for the purpose of symmetry. Oh yes, and now I know that the brake pivots for Nuovo Record and Super Record, also fit Triomphe and I guessing Victory brakes as well.

I decided to install the Athena derailleur with a 28T cassette.

There were very few 6 speed cassettes made, most were made by Suntour and none in Shimano HG (see below); if you find one they are usually very expensive. What I used was the 5 cogs attached to each other from a 7 speed cassette.
A Shimano 6 speed freehub is a Uniglide and 7 speed is a Hyperglide (HG). Normally one would attach a seven speed cassette with a 13T spacer and an 11T end piece with a lockring with HG. The last five cogs that are attached are a 18-28T, meaning if all the 7 cogs were used together you would have a 11-28T cassette. The Uniglide (UG) came as separate cogs and spacers, while the HG came as a cassette where most the cogs are riveted or screwed together. The UG locked the cogs on the freewheel using the threaded end of the freewheel and with a 13T threaded cog (one issue with the Uniglide was the lack of a 11T 0r 12T cog). The advantage of the middle freehub in the above photo, (Uniglide Compatable) is you can use either UG or HG cogs and either the 13T UG lockring or the HG 13T/11T/lockring system. However I have the proprietary Uniglide freehub, which is not compatible with HG cassettes; the reason is the addition of a wide spline designed to keep the Integrated Glide (IG) cogs lined up in a predetermined alinement (the ramps cut into the cogs aid in shifitng as long as they are lined up properly). Due to a lack of a wide spline, HG cogs or combined cassettes will not fit on a UG freehub. However, since the wide spline is created by narrowing the adjacent spine, all that is necessary is to grind off 1/3 of the wide spline in the cassette and it will slide right on (I did this first with a hacksaw to create a squared off edge on the spine and then a Dremil tool to remove the rest of the metal; and viola! A 5 speed cassette 15-28T and a 13T threaded lockring, to create a 6 speed 13-28T cassette! I rode this combination up a steep fire road and the 28T cog is plenty low for any purpose I can imagine (any lower and you would be able to walk faster).

The question to me is, does it fit the bike? My other choice is tracking down a Victory derailleur (there is currently a fairly pricey long cage version on ebay). I'm kinda stuck on the Victory right now, but I could probably live with the Athena. I'm not really concerned with function at this point as they all work well enough for what I have planned.

The photos show the newly installed Athena derailleur and a photo of a Victory.

I have also customized the shifters. The common Nuovo Record shifters for braze-ons and downtube clamps have a plate at the end held down with a screw. The Gran Sport on the other hand have a larger turban style tightener but they are not made for braze-ons (at least I have
never seen them). The clamp-on for the Gran Sport shifters have a threaded stud rather than Nuovo record that a simulated boss the same as the braze-on they also attach to. In order to use the Gran Sport style, all that was necessary was to install a threaded stud into the turban and screw it into the braze-on boss. The pressure it exerted on the internal parts of the shifter appears to be about the same as the bolts, as the shifters works the same, but I now have the large turban top cap to adjust the tension with.

For additional posts on this bike go to 70's Olmo Grand Sport

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