It's likely the frame. My (700C) P/R does the exact same thing.
Fortunately the bike has horizontal dropouts so you can adjust the
wheel so it's centered -- at least that's what I do. And FWIW, I
did have the alignment checked on my frame, and the chainstays are
correctly spaced with respect to the BB. [photo @
http://flickr.com/photos/jimg/2319869141/]

-Jim G





--- In KOG@yahoogroups.com, Daniel McMartin <mcmartind@...> wrote:
>
> > KOGs,
>
> I joined the group last month, but haven't had anything to
> contribute, or ask, until now.
>
> > I just finished building the wheels for my new 650b P/R. I
used
> > synergy asymmetric rear laced to ultegra 9spd hub. Both the
park
> > dish tool, and flipping the wheel in the truing stand tell me it
is
> > well centered. When I mount the wheel (snug in drop outs) it
is
> > off center towards left (non drive side). I realized I didn't
> > space the 130 mm hub out for the 135 mm dropouts. Could that
be
> > the problem?
> >
> > I stole the exact same wheel from my wife's bleriot (also
135mm).
> > Her wheel was built by someone far more competent than me, and
> > appears to be spaced out to ~133 mm (2 mm on left, 1 mm on
> > right?). A quick check with dish tool says her wheel is also
well
> > centered.
> >
> > When I mount her wheel on the P/R it is off center to left, not
as
> > much as my wheel, but still slightly off. Could this be the
frame?
> > Should I simply dish the wheel more towards drive side so it is
> > centered in frame? Bring it to Bike shop? Just ride it (that's
> > what I did today…couldn't help myself).
> >
> > Any help is appreciated - dan
> > .
> >
> >
>