This is the quote out of my WarbirdTech book on the F-104 on tires:
"Tires can be one of the more critical parts to obtain, because they typically only last about 15 landings. When your supply of tires is gone, you are looking at a $75,000 custom tire order from Goodyear."
My recollection (I'm looking for sources to substantiate) is there was very little room to house the retracted landing gear in the lower fuselage and super-high pressure, narrow tires were required.
BTW, my Dad was an aircraft tooling specialist on the F-104 while he was working for Lockheed Aircraft. It was a lot of fun to go visit him on the assembly line in those days.
Dan