Marc, and all:
Having a Campy crank conversion to a 74 mm bolt circle diameter, and having tried to mount it to a ~ '74 Raleigh Pro myself, I might have some insight.
Topic 1: Not sure what you mean by 'press fitted', but the conversion I have works great. And yes, drilling a double crank gives you holes in the flutes of the crank spider, but I've been standing on those things for years with my 200+ pounds and they're still in great shape. I have the original Campagnolo bolts that were not in the #17 Campagnolo catalog that have a threaded bolt with an expansive head for the larger diameter holes of the Campagnolo inner chainring, and a sleeve that acts as a spacer (which rusts). It was first used w/ a granny and half step of 28 x 48 x 53, not a great combination with the Campy crank. My 28 chainring was an Avocet which had the larger bolt holes. I think it's Bob Frietas who will drill out a modern TA chainring to fit those same bolts, and I acquired one in 32 teeth for the Pro.
The combination was good and solid, but a 28 will allow the chain to be trapped between the chainring and crank spider, which can be an absolute bit** to get out! I finally decided to only shift into the granny when the chain was on the largest cog in back. That bike has now reverted back to Stronglight crank/TA rings which don't have that problem, and is a pretty elegant solution.
A 32 tooth chainring won't trap the chain and I had a 32 x 42 x 53 setup on the Raleigh Pro. The spidery TA matched the super record rings in all but color, really looked nice. However the alpine setup didn't shift worth a da**. Modern front shifters don't work well with the narrow chainring setup, and parallel plate derailleurs just don't do the middle ring well. A half step and granny does a great job though, and I've been considering putting that back on the Raleigh. I saw an in between Suntour front derailleur at the Velo Orange booth with a non parallel plate setup and no shifting ridges that unfortunately got away from me before I could grab it, but I'd love to try that out sometime.
I think that as long as you dish the wheel to get the freewheel as much to the right as possible and the crankset as close to the chain stays as possible, even the shorter stays of the Raleigh will allow good alpine shifting if you can fix that middle ring shift and pretty good chainline for half step, especially with the modern 6, 7, 8 speed chains available today that flex much more.
I tried different derailleurs with it, first traditionally the Rally and NR back & front. Crappy shifting. Then a NR w/ rally cage plates, about the same, maybe worse. I'd probably stick a Duopar on the back just 'cause I have one, or maybe one of those Simplex JUY in metal, which I don't. The Campy NR in front works great as a triple for half step as long as the chain isn't hanging on the lower roller of the cage, which it will with a wide range 28 - 53.
Topic 2: Going with a pure Campag NR BB may be ok for show, but for a user, I found the old style thin BB cups and non hardened axles didn't hold up that well. Originally I couldn't find a Campy triple BB, and ended up with a cyclocross BB, which used with a 1 mm spacer on the fixed cup, got almost perfect minimal chain stay clearance. Two years and a few thousand miles later it was toast. I've since been using an American made ti axle w/ American Classic BB cups and sealed bearings that are adjustable from both sides. It's worked remarkably well in the long run. I didn't like the Phil BB design with the inboard bearings. It felt like it was warping to me when I really stood on it. Lately I think the BB's from Velo Orange might be a good solution. They told me that Campagnolo doesn't have the JIS tapers like the BB's they sell, but Phil's website indicates that the older Campagnolo stuff is JIS. I figure once you've got the right size down, it would be a really nice solution.
Randonneuring a Raleigh Pro sounds like fun, but mine is the stiffest riding frame I own. It sure goes where you point it, but doesn't absorb much shock. Maybe a good set of Grand Bois 29 mm baloney skins??? at a reasonable pressure?
Happy trails, and good luck with the conversion. The Campy triple really looks great on a Pro! I'm sorry I never got a photo.
Dan Artley in Parkton, Maryland USA
Archive-URL: http://search.bikelist.org/
Good Evening Listers:
*Topic 1*
Please weigh in on fitting a bike with an original NR Triple versus a converted NR Double.
Monsieur Freitas pointed out that the conversion gives you many more gearing ratio opportunities. Other than that I have heard that the original NR Triples, which are press fitted, are prone to failure under heavy use. Are the drilled and tapped conversions more durable?
I am constructing a "Randonneur" out of a '74 Raleigh Pro and am pondering if I go with an original triple or a conversion.
*Topic 2*
Please let me know what is the appropriate NR BB and axle length for a NR Triple for a 68 BB width (including cup thickness). Also does a conversion use the same BB?
Thank you.
Marc Winnikoff
Santa Barbara, CA USA