Ok, all this "Mexico" misinformation is making my brain hurt. I really hate repeating myself, and not too fond of typing either.......guess I'm not a very helpful member of the list. :-( I realize everyone is just trying to offer their opinion in order to formulate an educated answer to the question So, again I'll add the little knowledge I have on the subject to help.
The origin of the "Mexico" style Campy crank started when Merckx had his '72 Mexico Record attempt Campy cranks modified. The crank arms were reprofiled (especially at the dustcap area) and the milled flutes in the spider arms were cut out.
From that point on, the high end framebuilders started to offer this "Mexico style crankset. Typically seen on the Italian pantographed Super Record bikes. This was typically not available as a separate purchase to the consumer, but I'm sure could be had if persistent. It is important to note that these modified Campy cranks were not modified by Campagnolo. "Mexico" cranks modified by a separate company/s. In fact, this modification voided Campy's warranty right from the getgo. However, I doubt many customers were ever told this. I don't know how many companies performed this mod., but my guess is just one or maybe two. I don't know the name of the company/s. This was probably performed by the same source/s that did the pantographing for all the Italian builders.
I have seen 4 versions of the "Mexico" style crankarms:
a) reprofiled arms with cut out spider. b) reprofiled arms without cut out spider. c) reprofiled arms (more heavily at dustcap area) with cut out spider. d) reprofiled arms (more heavily at dustcap area) without cut out spider.
"a)" & "b)" were the most common, "c)" & "d)" are very uncommon.
The arms were always polished and not reanodized after that. A stock Campy crankarm was first machined to the desired profile, then the machined areas were polished and the remaining anodizing was removed mechanically via the buffing wheel. Once the job is finished, they don't remove the anodizing off the sides and back of the spider, that is left intact. The result is a beautifully modified Campy crank with a raw aluminum mirror finish. Very pretty, but very susceptible to oxidation.
NOTE: Campy cranks that had the spider cut out, but not the arms reprofiled are not considered to be "Mexicos", just your run of the mill bitchin modified Campy crankarms. An example of this is on the Bianchi SuperCorsa.
The little black specks that can be seen in used "Mexico" cranks IS oxidation, as Tom Dalton speculated. If this condition is still visible after hand polishing, chances are it will never come out, even with machine polishing. That is unless you don't mind having your crankarm buffed to extent of resembling a mirror polished stalk of celery. :-) This decay is typically very deep, and is due to the raw aluminum finish being neglected.
Their have been other manufacturers that produced stock cranksets that looked very similar to the Campy "Mexico" style, but only a Campy Record crank that was modified with this "Mexico" treatment should be referred to as a "Mexico"......my opinion.
As Matt Gorski mentioned earlier, the "Mexico" modification was also performed on Campy Record calipers. This mod. was done to the pre '83/4 calipers, the ones where "Campagnolo" was spelled out in block letters on the stirrup arm, as opposed to the cursive font. The "Mexico" mod. on the brakes removed material so as to create more of a triangular cross section to the arms, as well as rounding many of the edges. Interestingly enough, Campy's introduction of the new style arms (cursive font) was almost identical, in cross section, to the "Mexico'd" mod. And like the crankarms, the "Mexico" calipers were raw aluminum with a mirror finish, front and back this time, and always pantographed with "Campagnolo" on the left arm, and the framebuiler name on the right arm. Mexico crankarms were sometimes not pantographed.
"Mexico" crankarms were offered by almost all the high-end Italian framebuilders at one time or another. "Mexico" calipers less common.
I have never heard of the "Mexico" mod. referred to any other Campy component other than the cranks and calipers. However, when you think about it, there is a style of pantographed Campy NR brake lever that might qualify as "Mexico". There are some NR levers that have the vertical Campy logo ( CAMPAGNOLO") removed. Then, that area is pantographed with the framebuilder s logo/name. Then, the sides of the lever are cut out. The "cutting out" of the sides of the lever is common amongst panto'd levers, but not the removal of the Campy logo. Just food for thought.
Hope I've added some useful info.
Marc Boral Long Beach, CA
-------Original Message-------
From: Eric Elman Date: Monday, June 10, 2002 19:02:37 To: classicrendezvous@bikelist.org Subject: [CR]Campagnolo "Mexico" Cranks Questions
I know that the Campy NR/SR cranks with the "Mexico" treatment had been discussed a long time ago but I admit I was not paying much attention back then. Couple of questions. 1. What company did the machining and polishing? 2. Where they all done exactly the same or are there differences? 3. Were they available only on certain bikes (like my OLMO) or available individually? 4. Were they regular cranks that were de-anodized then machined? 5. Were they always polished aluminium and not anodized? On this last question, up till now I have only seen polished ones but I just recieved some jpegs of a very nice OLMO for sale on the Campy Only site. This OLMO has the Mexico'd cranks but while the arms are polished and shiny, the spider part is anodized just like normal. How could this affect be achieved and how common was this effect on them? 6. Lastly, my set is all polished aluminium but despite how much I polish and buff them they have darker "stains/speckles" about the size of crushed pepper in them that will not come out. The stains are only noticable when you look closely but are there none the less - any ideas on the cause and any possible way to eliminate these dark marks?
Eric "full'a questions tonight" Elman Somers, CT
_______________________________________________
.
-------Original Message-------
From: Eric Elman Date: Monday, June 10, 2002 19:02:37 To: classicrendezvous@bikelist.org Subject: [CR]Campagnolo "Mexico" Cranks Questions
I know that the Campy NR/SR cranks with the "Mexico" treatment had been discussed a long time ago but I admit I was not paying much attention back then. Couple of questions. 1. What company did the machining and polishing? 2. Where they all done exactly the same or are there differences? 3. Were they available only on certain bikes (like my OLMO) or available individually? 4. Were they regular cranks that were de-anodized then machined? 5. Were they always polished aluminium and not anodized? On this last question, up till now I have only seen polished ones but I just recieved some jpegs of a very nice OLMO for sale on the Campy Only site. This OLMO has the Mexico'd cranks but while the arms are polished and shiny, the spider part is anodized just like normal. How could this affect be achieved and how common was this effect on them? 6. Lastly, my set is all polished aluminium but despite how much I polish and buff them they have darker "stains/speckles" about the size of crushed pepper in them that will not come out. The stains are only noticable when you look closely but are there none the less - any ideas on the cause and any possible way to eliminate these dark marks?
Eric "full'a questions tonight" Elman Somers, CT
_______________________________________________
.