Just to clarify (I thought someone would chime in with this, but see that nobody has thus far...):
Campagnolo made road and track cranks every 2.5 mm from 165 to 180 in the case of "vintage" NR/SR. There were also "Junior" cranks of 150 mm length that were GS 3-arm parts. As Dale mentioned, probably 85-90% of the crankarms manufactured back then were 170 (road), so that's what is around today in the biggest numbers.
In road cranks, I have found 167.5 and 180 to be the rarest of all; 165s are available fairly frequently, as are 172.5, and to a lesser extent 175 and 177.5 mm ones.
In track cranks, since 165 was the de facto "track standard," 165 and 170 seem to be by far the most common lengths available today. Again, 167.5 seems to be rather rare for whatever reason, as does anything longer than 170 (which makes sense I think; more worry about scraping a pedal on a track than on the road in general IMO). I've only seen one set of Record Pista arms that were 180 - that's really long!!
Regards,
Greg Parker Ann Arbor, MI, USA
From: Huemax@aol.com
> Date: Wed, 1 Jan 2003 10:31:31 EST
> Subject: Re: [CR]Campy Road Crank Lengths
> To: teaat4p@yahoo.com, classicrendezvous@bikelist.org
>
>
> In a message dated 12/31/02 10:54:46 PM, teaat4p@yahoo.com writes:
>
> <<Did Campy make road crank arms in 165 or 167.5? >>
>
> Yes, they did, indeed I have both 165 and 167.5mm STRADA set 151 BCD.
>
> Is there anyone who has an extra chain ring 151 BCD, 50, 51, 52T, and
> willing to sell or trade?
>
> Happy New Year!
>
> KEN TODA, High Point, NC, very wet New Year's Day!