[nhramnl]

I think everyone would agree that Phoenix bias plys (particularly when they were Firehawk or Firestone) were the worst for air loss over time. That's pretty much where the whole "dish soaping the inside of the tire" thing got started. I currently have a set each of Phoenix bias plys and radials and can tell you from first-hand experience that neither version leaks at all. Phoenix/Firehawk/Firestone bias plys were the tire of choice among Super Stock racers for years, but the constant air loss made them a huge pain live with.