a. How to know when tires need replacing.
Look for the wear indicators in the major grooves. Replace the tire immediately when the tread wear indicator shows.
Check for minimum tread depth using the tread depth measure.
Perform a visual inspection of the tread and sidewall. If there is any exposed steel or fabric and if any material is visible, have the tire(s) replaced immediately.
b. How to replace a tire
Rims of different diameters and tapers cannot be interchanged. The top right diagrams illustrate the difference between rims of two different tapers and diameters.
Pry off the wheel cover.
Loosen the lug nuts.
Jack up the vehicle about 6 inches off the ground.
Remove a tire and wheel from a vehicle.
After separating the tire and wheel, replace with a new tire.
Check tire balance.
Lower the vehicle to the ground fully and remove the jack. Finish tightening the nuts and replace the hubcap.
Install the newly fitted tire and wheel on a vehicle.