Stu:
There are actually two parts to this tubeless tire debate. The tubeless
tire and the later safety rim. The TD, TF, MGA, and maybe early MGB all
did not have safety rims.
I checked into some history and tubeless tires came out as early as
1957. These were early biased ply or belted (who remembers those) tires
used on the same rims as the tubeless. I used tubeless belted tires on
every day cars for about 10 years (1960-1972) before radials became more
common and less expensive.
Later, about 1967 (GM's Cadillac, it's premier line and usually the
first with new inovations in 1968.) the safety rim came out. It has an
extra hump so the bead of the tire pops over it helping to lock the tire
on the rim. What would be interesting to know is if some older cars
came with safety rims and tubed tires.
One source says the safety rim was mainly to keep the tire seated during
deflation or low tire pressure. The problem of deflation became more
pronounced as tire widths and adheasion increased.
So there was a period of about ten years in which new cars had tubeless
tires without the safety rim.
IMO, the deflation problem could have been more pronounced years ago
when the non power tire changing equipment was used. At one time shops
used armstrong bars, levers and soap on the rim to get the tire on.
Today, many shops don't use the soap. The soap I think is part of the
problem. It doesn't allow the bead to "stick" to the rim. With clean
rims, and no soap, I would think the bead will stay much better.
Also tire inflation could be a problem. Low tire pressure as the 18 lb.
recommended in manual could allow the bead to unseat. That's another
reason to use 24-26 PSI.
Lastly, doing much hard cornering before the tires have had a chance to
set and stick to the rims could result in a deflation problem.
Unless one is using radial tubes specifically designed for use in
tubeless tires, I don't think there's any benefit to the tubes. The
added weight, internal friction, and heat would be just as much a safety
problem as sudden deflation.
Blake
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