Self Supporting Technology (DSST) is the name given to Dunlop run on
flat tyres. They are designed to carry on running when the tyre is
punctured, the limit is 50 miles and Dunlop also say that you should not
drive at speeds of over 55 mph.
The Dunlop DSST has many attributes to it some of them are as follows:
The construction of the sidewall has been stiffened so
that it can carry the weight of the car even if there is no pressure in
the tyre. The picture above illustrates this best, standard tyres would
collapse with no air and perish if you tried to run them flat. This is
because these tyres have very thin sidewalls. Where as the run flat
would not loose shape even when driving at speed of 50mph because the
sidewalls have been stiffened and beefed up. The downside to run flats
is that the ride is fairly uncomfortable compared to standard tyres. A
run flat doesn't have any flex in the sidewall and is more rigid because
of the solid rubber ring in the sidewall. Driving over pot holes and
jumps can be uncomfortable.
Dunlop does claim that their run flats have a better
solid ring compound and this special compound allows the tyre to flex
making the tyre unbreakable or indestructible. Dunlop claim when their
runflat is running on zero pressure handling, acceleration, braking and
steering control are unchanged.