The comparison with a touring frame is a good one. Cross frames generally have slightly slacker head angles and more rake to keep a proper trail with larger tires considered. Of course forks are longer for tire clearence. BB drop is also less and coupled with a slightly longer chainstay gives plenty of tire clearence. Modern cross bikes typically have more bb drop than on topic ones as toe clips are no longer used competitively and a 32 or 34c tire gives plenty of clearence with 70mm of BB drop. That's a basic primer, but the differences are very small between a road and cross bike.
Jonathan Greene Oviedo FL
Sent from my iPhone
On Jan 15, 2010, at 5:04 PM, Jack Gabus <jgabus@gmail.com> wrote:
> Gang:
>
> While being inundated by the fixed gear crowd I have seen another
> outcropping of the fad. That being the conversion of an old road
> frames and
> converting it to some sort of cyclocross rig. And no I don't mean
> what
> Fisher and Ritchey were doing in Marin Co. making MTB's. I was to
> believe
> that the geometries of the two were quite different or maybe
> slightly so, a
> la BB heights. Can the gang shed some light on this for me. I am
> sure his
> eminence Mr Sachs can chime if he is checking the list today.
>
> Thanks,
>
> Jack
>
> --
> Jack Gabus
> 310 490 3784
> jgabus@gmail.com
> Laguna Beach, CA
> USA