I have had quite a few Mexico cranks pass through my hands and still
have several. I took a comparison photo of three Colnago cranks last
year during a bit of a rationalisation. Check the reverse side of the
cranks in the Mexico album
http://au.pg.photos.yahoo.com/
What was evident is that there were differing amounts of material left,
after milling, to re-inforce the crank - as seen by the photos. The
machining on the crank spider arms often had waves - including the
groove in the crank arms - which is the sign of a totally hand crafted
(held?) modification. It seems as though some cranks were pulled from
production before and after stamping by Campagnolo - no fixed rule.
The polishing of the cranks to the mirror finish would help compensate
for the loss of material bulk in regards to strength which is in accord
with recent posts concerning the smoothing of Campy cranks to prevent
cracks starting.
Still, you wouldn't find me pushing a Mexico crank on an assault of the
Pyrenees - more likely on a Sunday mornng coffee run where the true
value of the crank can be justified - you know what I am talking about.
Greg Softley
Still looking for Bi-valents!!!!
Coffs Harbour
Australia