It is quite easy to differentiate between a 144mm bcd chainset and a 151mm bcd. With a 144mm bcd the the chainring bolts are about three mm from the edge of the chainring circle - noticeably close. With a 151mm bcd the gap is much larger - 6mm.
Hilary Stone, Bristol, England
brianbaylis@juno.com wrote:
> Andrew,
>
> If the cranks are original to your '74 paramount they should be 144 BCD.
> But if they're 151 then they're 151. The chainrings are out there in bo
> th 1/2x1/8 and 1" pitch.
>
> Brian Baylis
> La Mesa, CA
>
>
>
> -- Andrew Gura <agura@earthlink.net> wrote:
>
>
> i'm wondering how i tell what BCD my campy pista cranks are -- they're t
> he stock equipment on my 74 paramount.
>
>
> is there a definitive guide somewhere?
>
> i tried the sheldown brown method (http://www.sheldonbrown.com/gloss_bo-
> z.html) and my chainring bolts seem to measure just below 90mm c-t-c but
> that would make them 151BCD and i think the bike is too new for that. o
> r maybe i'm wrong.
>
>
> thank you
>
> andrew gura
> silver lake, ca