Last winter the RF R4 went flat. Didn’t think anything of it, local Tire Shop checked bead and stem and,remounted it.

Come back a few weeks later, flat again. Spray with water, don’t see any bubbling, refill. Weeks later, flat again.

Brought it to Tire dealer and they put it in the tank. Finally found bubbling on the side of a tread block. But when they looked inside, they couldn’t find any puncture. Wound up putting a tube in it.