15" tires

Still a bit out there for 15 inch tires. However the selection is "limited"
For example looking to get 255/60R15 tires?
You got maybe 4-5 selections for street radials... That's it.
Cooper.
BFGoodrich.
Hankook.
Mickey Thompsons.
Mastercraft.
Not the greatest selections, I Like the Cooper Cobras the most, Mickey Thompsons are a good second. (Cooper owns Mickey Thompsons)
BFGoodrich and Mastercraft are "ok", Mastercraft's are about the cheapest but don't seem to last that long , same with BFG's.
Mastercraft is also part of Cooper.
I have no experience with the Hankook so I can't say.
There are still a few of the older Firestone Firehawk Indy 500's 15 inch tires around but it's been discontinued, the newer Firehawk series are pretty much 16 inches and up.
- Again I can't comment on this exact tire as I've never used them before. I've used Firestone's Destination A/T's in my old 1983 Dodge Ram and thought they were pretty decent.
There's more out there, although off-brands are the name of the day...
Performance Plus shows 10 different tires in P255 60R15
Buy Passenger Tire Size 255/60R15 - Performance Plus Tire
(Radar, Vitour, Nankang, and Grand Prix in addition to the usual T/As, M/Ts, Coopers, Hankook and 2 different Mastercrafts)
Ebay shows all the usual suspects; plus Tornel, Starfire and Hercules...
And I'm sure there's more if I look around. I know most are secondary brands made by the major manufacturers, or offshore manufacturers- but there's choices out there. Not all sizes, but they're around.