If I'm remembering my models correctly, the 6600 is a horizonal parallelogram, while the 5500 is a conventional drop parallelogram. The 6600 is not quite the "slant parallelogram" geometry patented by SunTour, but closer, so it should maintain a more nearly constant distance from the cogs and theoretically shift better, although in fact the 5500 itself shifts very well indeed. The 5500 is more classic looking and I would therefore think more desirable on any bike made before 1980.
Regards,
Jerry Moos Houston, TX
wayofftheback <wayofftheback@yahoo.com> wrote: Hi, All,
As I am curious, let me pose this question: Which Simplex Super LJ do you think is better and why: the 5500 or the 6600?
Regards,
John Taglia
Chicago, Illinois