If your vehicle is showing outer edges of the tire tread are worn down faster than the center, here are the most likely causes and the parts you'll need to fix each one.
When tire pressure is consistently too low, the center of the tread bows inward, forcing the vehicle's weight onto the two outer shoulders of the tire. This is the most common cause of dual-edge wear.
A slow leak at the valve stem causes continuous under-inflation that ruins the tire edges. This frequently occurs when old TPMS stem seals are reused instead of replaced during a tire installation.
Front tires naturally scrub their outer edges during cornering and steering. Failing to rotate the tires regularly allows this edge wear to become highly pronounced compared to the center tread.
Corrosion or a slight bend in the wheel rim prevents the tire bead from sealing perfectly. This leads to a chronic slow loss of air and subsequent under-inflation wear.