Self-sealing tyres are essentially the same as conventional tyres but with the addition of an internal self-sealing gel that reacts in the event of a puncture to reseal the tyre and allow you to continue driving normally. The benefits are that they do not suffer from the harsh ride quality usually found with run-flat tyres, which use stiffer sidewalls and structure to maintain their integrity in the event of a puncture. The downside is that self-sealing tyres can only cope with punctures that are limited in size, and damage to the sidewall will still result in deflation, unlike a run-flat tyre.