Your tires are the only part of the vehicle that touches the road. Worn tires grip less, especially in rain and snow, so it pays to check them regularly.

Check the tread depth

Tread depth is measured in 32nds of an inch. In most US states, 2/32" is the legal minimum, and many tire experts suggest considering replacement well before that, especially if you drive in wet or snowy conditions.

  • Wear bars. Most tires have small raised bars across the bottom of the grooves. When the tread is level with these bars, the tire is worn out.
  • The penny test. Put a penny into a groove with Lincoln's head pointing down. If you can see the top of his head, the tread is likely at or below 2/32".
  • The quarter test. With a quarter, if you can see the top of Washington's head, the tread is around 4/32" or less.

Check several places across each tire, because tires do not always wear evenly.

What uneven wear can mean

  • Wear in the center: often a sign of too much air pressure.
  • Wear on both outer edges: often a sign of too little air pressure.
  • Wear on one edge: can point to a wheel alignment problem.
  • Cupping or scalloped dips: can be caused by worn suspension parts or wheels that are out of balance.
  • Feathered tread (smooth one way, sharp the other when you run your hand across it): often an alignment issue.

Look at the sidewalls

Bulges, deep cuts, cracks or anything stuck in the tire should be looked at promptly. A bulge in the sidewall can mean internal damage, and the tire may fail.

Tire age matters too

Rubber ages even if the tread looks fine. The last four digits of the DOT code on the sidewall show the week and year the tire was made (for example, 2321 means the 23rd week of 2021). Check the tire or vehicle maker's guidance on how old a tire should be before it is replaced.

Keep the pressure right

Check your tire pressures about once a month, when the tires are cold, using the figures on the sticker inside the driver's door. Correct pressure helps your tires wear evenly and last longer.

This article is general information. Every vehicle is different, so check your owner's manual and have a qualified technician inspect any problem you notice.