While it usually only takes a few revolutions of the tire to get an effective seal, several factors affect sealing time. They are: -Size of the hole in relation to the depth of the rubber. The larger the hole, the thinner the rubber depth, the longer it could take to seal. -Length of time the object has been in the tire. Rubber has memory. The longer the object stays in the tire, the more time it could take to seal. -Angle and placement of the puncture. Objects that pierce at an angle can cause the resulting hole to have more torsion and flex as the tire rolls. This activity varies the flow of the fluid and matting of the fibers and can result in slower sealing times. Conversely, very small angle punctures often seal the quickest. Punctures between the treads can some times take more time especially if they're made by larger objects. Punctures in the side wall, especially straight in, are the hardest to seal and generally take longer... and larger holes in the side wall of well-used tires may not seal at all. -Age and hardness of the tire. As mentioned earlier, rubber has memory that it loses with age becoming harder. The harder the rubber, the longer the sealing time, especially with the larger punctures.