If your vehicle is showing visible bulge or bubble on the tire sidewall, here are the most likely causes and the parts you'll need to fix each one.
Hitting a pothole, curb, or road debris pinches the tire against the wheel rim. This tears the airtight inner liner, allowing air to escape into the sidewall plies and form a bubble.
If the tire bead or inner liner was torn by tire irons or the mounting machine during installation, air can leak into the sidewall structure and create a bulge shortly after leaving the shop.
Driving on a severely under-inflated tire causes excessive sidewall flexing and extreme heat buildup. This breaks down the internal structure, leading to ply separation and bubbling.
A structural flaw or contamination during the tire's manufacturing process can cause the internal layers to separate prematurely. This usually appears very early in the tire's life without any impact.