Strange campagnolo crankset

[ThePrivateer]

As I admitted before I am an mtb guy - an have little knowledge of road bikes.

But last year I came across an old Legnano gran premio - in quite a sorry state I have to admit. Right now, I’m taking it apart.
And I have a question concerning the crankset.
It is a campa piece from the 70s.
The cranks are made from aluminium (at least they are non-magnetic). The right crank has a three arm spider with two train rings that are bolted.

The chain rings have campagnolo engraved and have a lot of the drilled holes in them.

So it could be a grand sport, but those are supposed to have bolted chainrings, and the cranks should be made from steel. The more upmarket crank sets should have a five arm spider.

Anyone of you have a clue?
Did someone drill the holes himself - as a kind of for weight saving technique?

 

[non-fixie]

Nuovo Gran Sport.

 

[Canuk]

The steel version of this was lovely

 

[ThePrivateer]

compared to the mountain bike cranks this shows a lot more attention to details (bolts, routed crank arms …) but also it is from 20 years prior to my usual stuff.
What do you think about the chainring holes? Did the rings come like that?

 

[juvela]

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"What do you think about the chainring holes? Did the rings come like that?"

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do not recall manufacturer offering a "bis" (relieved) edition of this set

if one looks closely at the relieving it can be seen that there is some variation in the radial distance out from the chainset's centre of the individual holes

if the relieving had been "factory" this variation would not be present

subject set be model Nr. 3320 Gran Sport (not Nuovo Gran Sport)






[images courtesy of VB]
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[sjcprojects]

Yes, the chainring holes are a classic bit of ‘drillium’, drilling holes to save weight, DIY style.

It was pretty common in the 70s in particular.

 

[Nob]

Drillium for sure

 

[ThePrivateer]

It is amazing that all these old pieces have their own stories.
I can almost see the guy - like me - in the basement working on his bike. ( tinkering to save 10 grams of weight
But some 50 years ago when I was a toddler.

Thank you - you guys are the best !

 

[juvela]

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the bottom bracket spindles for this "family" of chainsets: Sport, Gran Sport, Nuovo Gran Sport have black oxide finishes which distinguish them from the satin chrome finishes of the Record and Nuovo Record models




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[ThePrivateer]

I will check that. But I have yet to remove them - it look to me like they have never been serviced.
Do they open the same way as “normal” BSA BBs? In the back of my head I know something about older French/italian bearings with different threading? But I cannot put my finger on it.
For now I put some wd40 on it