Now if my memory serves me right, the inside of a tubeless tyre was nowhere near as smooth as the tubed equivalent. This was considered liable to puncture the inner tube if one was retro fitted and I don't know if that has changed.
Yes, probably. I think they gave several reasons - possibly it wasn't as critical because the old cross-ply tyres didn't last as long as a good steel belted radial - they also said there was more flex in the sidewalls of a radial - plus, they were getting toward lower profile tyres, though not as low as some nowdays.
The next time you are in a tire story, LOOK at the inside of a few tires. There isn't THAT much difference. AND.....some rims still require a tube, or at least at one time they did, and since NOBODY is making "tubed" tires anymore.............
In the 70s there were many cars around with tubed radial tyres and with tubeless tyres with tubes in. One issue with putting a tube in a tubeless tyre was getting all the air out from between the outside of the tube and the inside of the tyre casing as the tyre would seal on the rim as the tube expanded trapping air between them. Another issue was balancing, it was notoriously difficult to balance a tubeless tyre with a tube in back then.
Folks, thanks for all the kind words encouraging me to get a second opinion, i took it by a regular tire shop and they laughed at me when i told them i was going to replace the tire due to nail (roofing nail) damage and plugged it, they said they have seen worse and it wasn't even close to side wall, wish i could attach the picture here ... at least for now i have decided to take a chance with the plug .. did it last friday and so far no change in pressure in tire or no indications from TPMS either, with almost 6" of rain here in last couple of days I think i am going to call it good THANKS AGAIN