>                     RPM X Tire diameter       (say 25" tall for example)
>MPH =          ~~~~~~~~~~~~~~~~
>                    Final drive ratio X  336

And if anyone is feeling lazy, I have a nice Lotus spreadsheet I wrote a
while back that calculates all this in a table of rpm versus speed that I'll
send them.  I posted it a year or so back but finding it in the archives may
be hard.

John
vwbus@mindspring.com