On 2004-05-21, penned:

My local bike shop says the 4500 has been discontinued and is been
replaced by the 4600, yet I can't find any information about this
4600. Has anyone heard about the 4600?

This shows a 4500 and no 4600:

http://www.trekbikes.com/bikes/2004/mountain/index.jsp

--
monique