Tire ABC_Time to replace tire
There are many reasons why tires should be replaced. Here are some recommendations based on currently available information.
Tires should be replaced when their remaining tread depth is no longer appropriate for the weather conditions expected to be encountered. Tire recommends replacing tires at approximately 6/32" of remaining tread depth for driving in snow, 4/32" for driving on wet roads and 2/32" for driving on dry roads.
Most small cuts and punctures in the tread area (up to 1/4"in size) can be repaired by trained personnel using industry-approved methods. These tires can be returned to service if they have not been driven on while flat or with very low inflation pressure.
Tires cut or punctured in the shoulder or sidewall areas, as well as any tires driven on while flat or with very low inflation pressure even for short periods of time are often damaged beyond repair and should be replaced. Driving on a tire while flat or with very low inflation pressure will permanently weaken the tire's internal structure, rendering it more susceptible to catastrophic failure.
Tires that exhibit any bubbles, blisters or bulges, or have large cuts, cracks or other significant damage from road hazards in the tread, shoulder and/or sidewall areas should be replaced. Only inspecting the tire's innerliner after dismounting the tire from the wheel will reveal the probable cause and help determine if the tire manufacturer's workmanship and materials warranty applies.
Tires that have been in use for five (4) years or more should be carefully inspected periodically for external signs of aging. While this inspection will confirm the condition of the exterior rubber, it cannot assess internal degradation or damage. Previously unused, never-mounted tires should not be put into service if they are more than six (6) years old even if they were properly stored.