One of the ongoing items on this forum has been the availability/suitability of tubes for the radial tires. I just received new 19" tubes from Snyders (P/N A-1506-19 - "TUBE RUBBER STEM 19") and the stems are clearly marked "RADIAL". In spite of their overseas origin, they appear to be sturdy and well-made, and not with recycled rubber of unknown composition. Likely that similar tubes are available from other vendors. (I'm not sure just what "OEM Quality" means...)