A tire bead is the edge of a tire that sits in the provided groove on the rim of a wheel. A fully inflated tire causes the tire bead to grip the rim in such a way to prevent the tire from slipping off the rim as the tire rotates on the road. However, there are certain conditions that cause the tire bead to “freeze” or “lock” up, making it impossible to change a tire if and when it goes flat.
Rust
Rust on a wheel rim collects in a thick layer around the groove where the bead of the tire sits. If this rust is all the way around the groove, the tire cannot be removed. You need a bead breaker tool to force the edge of the tire out of the grove. You do this by using the bead breaker to “crack” the rust going around and forcing the tire rim free.
Ice
Ice is another condition that frequently freezes the beads of tires to the rims. In extreme cold, there is no way to safely pop a flat loose. You will have to tow or move the vehicle into shelter to help some of the ice melt. Then you can use a bead breaker to break the bead and remove the tire.
Where to Get Your Bead Breaker