Rich,
I have a set of the Pro Trac 5.60.15 front runners mounted on a set of 15"x 4" Cragar fronts. I like the look of the outside tire face but with the inside wall, Coker leaves a thick step in the rubber which I was told is there for machining of raise letters or a side wall stripe which is left unfinished or uncut. It leaves this obtrusive 1/2" thick raised lip on the inner sidewall of the tire which looks sort of stupid on there? I called them and bitched about the design of it but that fell on deaf ears.
I then bought a set of the Firestone 5.60.15 tires which looked better but they too have this unfinished inner lip on the sidewall, although it's not as drastic as the hard edge found on the Pro Tracs. The Firestone's are more of a pie crust ridge which is nice tread design. I'm including pics of both so you can see them although the Firestone's are not mounted yet.
Pro Trac Outer Side Wall
Pro Trac Inner Sidewall (notice the hard edge or inner ridge on the inside wall)
And here's the unmounted Firestone showing outside wall
Still has this raised thick rubber ridge on the inside but not as pronounced?