COKER Tire 74715 - Simplex Servi-Cycle 26X3 CL.
I would say zero chance it will fit on the rim. These are a clincher style and are made for 20" motorcycle rims. Simplex Servi-cycles use a 26" bicycle style rim, which is actually 22 1/2" in diameter. If you saw this on eBay, they don't know what they are talking about.
Italy, Holland, USA, Australia and England all had Simplex brands. I think these tires may fit on one of those.
There is a lot of information on here about some various Coker Tires, as I went through much searching to find a tire that would fit on a Simplex Sportsman rim, which used a nominal 27 x 3 size tire, but the closest I ever got that worked was a 21 x 2.75 motorcycle tire, but I wasn't comfortable riding it at speed, as the tire was slightly larger than the rim, which was closer to 20 1/2". I spent an hour with the Coker rep at a AMCA show going through all the tires they sell, but no dice.
If you feel like reading about that story, look here:
http://www.simplexservi-cycle.com/index.php?topic=1434.0