I might be needing new tires, Im going to check the date on the 225R75/16 tires that are on there now.
Tire calculator says with the 225's.. If your speedometer readsmph, you are going about 57.1 mph with the 215's.
So they are pretty close in size. Should be good to go.
I bought the Greyhawk in May so if it has older tires, I will go with the 215's.
UPDATE: Tires were built 1116. So a around 2 1/2 years old. Should be OK for now.