Richard
275/60-15 is one hell of a tall tyre. Are they the sizes you are planning to run?
You're not building a tractor with a Cobra body are you?
I'm running a Bridgestone RE 710 on the rear, great tyre but at 255/60-15 not my ideal size. The Adelaide guys got a dealer down there (Stucky's?) to import a bunch a couple of years back. Don't know if they are still available.
Not as good a track tyre as Avid's, but streets ahead of Y352's.