I seem to see a counterbore in the _outside_ of the chainring bolt holes, for a chainring bolt or nut to nestle in, with NO chainring mounted to the outside of the spider arms. A normal track crank will have the counterbore on the inside of the spider arms, and a road crank will have no counterbore at all.
I'm gonna guess this is a regular 1/2" pitch AX crank that has been modified with a smaller BCD and no ability to mount a ring on the outside, for some strange reason. Could this have been "factory"?
Or I could be seeing shadows - could the Original Poster (crank owner Rick) verify whether there is a counterbore?
I also notice the pedal axle holes are regular size, but the "meat" around the hole is so bulbous that the extra-large AX pedal hole could fit there - making me think these started as forgings for AX pedals, but had 9/16" holes drilled for some reason.
Weird.
Mark Bulgier Seattle WA USA
Hilary Stone wrote:
>
> But this not a standard AX series crank as it has standard
> pedal threading ... and the spider does look smaller than
> standard to my eyes.
> 10mm pitch went onto until 1982 or 3; is this late 10mm
> pitch track chainset? Ax chainsets normally took standard
> 130mm bcd chainrings.
>
> Hilary Stone, Bristol, England
>
> Chuck Schmidt wrote:
> > Rick Gaytan wrote:
> >
> >> I stumbled upon this crankset yesterday for a good price
> >>
> >> http://images.vintagebmx.com/
> >>
> >> I figure it has to be a 10mm pitch one as a regular Shimano BCD
> >> sprocket is too big. Yes, no?
> >>
> >> It's stamped "For professional use only" on the back..I guess that
> >> counts me out :)
> >>
> >> Any Info would be highly appreciated
> >
> >
> >
> > Rick, the photo link shows a crank stamped "DURA-ACE AX"; the AX
> > Series of aero components (Dura-Ace, 600 and Adamas groups), not the
> > 10mm pitch track stuff.
> >
> > Chuck Schmidt
> > South Pasadena, Southern California
> > United States of America
> > http://www.velo-retro.com (reprints, t-shirts & timelines)