Rick are you saying the cokers won't fit ?
What I am saying is, it depends on what rim you have.
All the simplex rims up until the latest Sportsman rims are 22 1/2" outside diameter. These take the Coker 26 x 2.5" tire. I would venture to guess this covers 99% of all the Servi-Cycles built.
The 59/60 Sportsman used a rim that is 21 3/4 outside diameter. These are the CC rims. Coker states in their catalog that this is a European size, and is not compatible with a standard motorcycle 20" clincher tire, even though they are very close in size. Tires for these that Coker makes are 27 x 3.5 and 26 x 3. Get ready for sticker shock as these are $239 and $222 respectively.
EDIT: THESE TIRES DO NOT FIT.