The tread is in contact with the ground and naturally builds up heat the most, due to friction. Also, the ambient air temperature affects the internal temperature: and gas expands when heated, so pressure rises. Over-inflation is bad for tyre life.
The Soltex liquid heats up less rapidly than the tyre tread, and it tends to draw heat away from the inside of the tread material, slowing the rate of temperature increase.
Any type of rubber will suffer from friction and heat, and over time it will tend to dry out and crack. We’ve all seen how that happens to tyres as they age. In extreme cases the tyre layers may separate and fail.
The presence of the Soltex sealing liquid inside the tyre serves to soften and condition the tyre tread structure, slowing the tendency for it to crack or delaminate.
The result was conclusive:
Soltex-equipped drive tyres: average temperature 101.19° F
Non-Soltex-equipped drive tyres: av. temperature 114.32° F
Soltex temperature reduction: 11.5%