Sometimes you can bounce the tire on the pavement, or hit the tread
with the blunt side of an axe, and the sides will pop into place well
to seal. If you wet it down with a hose, it will help......
Assuming you can put air in fast enough to make it tight for a
might THEN. let the air out (maintaining the seal) and use green slime.
It won't take much....
Andy in Eureka, Texas