Things You'll Need:
- Vehicle with tires
- U.S. Quarter
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Step 1
Make sure your car is in park, park brake is on, engine is turned off and car is stationary. You will begin inspecting your tires from driver front, passenger front, passenger rear, driver rear. You will be inspecting your tires for 8 things: 1) Uneven tire wear; 2) Bubbles or bulges in your tire; 3) Uninterrupted cracks around the bead and the crown of the tire; 4) Age; 5) Excessive wear; 6) Tread depth; 7) Damage; and 8) Foreign Objects. Repeat this procedure for each tire on your vehicle.
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Step 2
A solid ring/crack around the bead or crown of a tire, especially if it gapes open, is an indication the tire will soon fail.First, inspect your tire visually. Look specifically at the outside edge where the tire meets the wheel (this is call the bead), and at the area where the tread meets the sidewall (this is called the crown). In both cases, look for a solid rings (cracks) all around the tire, or gaping open at points. Such cracks are created by running a tire low in many cases, and indicate the tire will soon fail. If any such cracks appear, it is time to replace the tire. Do not confuse these cracks for common weathering, which do not appear as solid rings or gape open. Cracks from common weathering are superficial and not dangerous.
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Step 3
Bubbles in the sidewalls of tires indicate damaged sidewalls, where air has leaked from inside the tire into the casing, creating a bubble. The tire needs replaced ASAP.Second, while inspecting for the cracks described above, also look for bulges or bubbles on the sidewall. These will typically be the width of the sidewall and are caused by an impact, such as against a curb or pothole. If a bulge or bubble appears on the sidewall, the tire needs replaced immediately. Some tires will have an indention in the sidewalls where the belts in the sidewall overlap and do not stretch as much as the surrounding sidewall. These are typical features of some tires and are not dangerous. Only bulges, where the sidewall is raised outward from the surrounding sidewall, are indications that the tire will soon fail and the tire should be replaced as soon as possible.
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Step 4
Nails, screws or other foreign objects in a tire will eventually result in a flat tire.Third, visually inspect the tread area of the tire. Like Step 3, look for bulges in the tread. Your tire likely won't have any such bulges, unless your car has developed a vibration that occurs at slow speeds to medium speeds (5-40 MPH). While you're looking for a bulge, also look for nails, screws and other foreign objects in your tire that may cause it to leak in the near future. 70% of tire failures occur due to low pressure. If you find a nail or screw in your tire, have the tire inspected and repaired if necessary at your favorite retail tire store.
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Step 5
Bald tires, or with steel cord showing, should be replaced immediately.Next, visually inspect your tires for baldness, especially around the outside or inside edge. You may also wish to feel for baldness or smooth areas of the tread and tread edges. You can do this by using the palm of your hand and very lightly and slowly rubbing it flat around the edges and tread of the tire. BE CAREFUL! If steel belts are exposed, the wires may cut your hand! If the tread is worn bald or smooth at any point, the tire will need replaced ASAP. The next layer below the tread that is worn smooth are the steel belts in the tire. Since steel belts hold the tire together, any tire with the steel belts showing is sure to fail unexpectedly. Immediately replace bald tires and tires with exposed steel belts!
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Step 6
Cupped wear like this can be caused by worn parts or infrequent rotation practices.Next, gently run your palm (as described above) across the tread area around the tire as far as you can reach and feel for uneven wear. You are looking for uneven wear on the edges, also called cupping. Tires that have begun to wear unevenly on the edges should be rotated more frequently, but they are not necessarily bad tires. These tires that have worn unevenly on an edge may also cause road noise (a hum) when the vehicle is driven. If uneven wear is severe, have the tire inspected and likely replaced at your local tire retailer, and your vehicle may also need the suspension checked and an alignment performed. Alignments are recommended every year.
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Step 7
Uneven diagonal tire wear like this indicates worn or loose suspension components in many cases.Next, using the same procedure above, check for uneven wear in the middle of the tread. This uneven wear will be similar to the cupped edge wear, but it will be across the entire width of the tire. You will be able to feel it with your hand. This kind of uneven wear is the result of worn or loose suspension components, and/or hard acceleration or braking, and can be aggravated by misalignment. If this kind of uneven wear is present, you should replace your tires ASAP. They are not unsafe, but will cause vibrations that cannot be corrected by balancing. You might also have your shocks and/or struts checked at a reputable repair shop.
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Step 8
Check the tread depth of your tires using a quarter, not a penny.Next, check the tread depth on your tires using a quarter. You can purchase a tread depth gauge, but that's not necessary if you've inspected your tires using the method and sequence outlined here. To check your tread depth, take the quarter, with Washington's head upside down, and insert it into a tread groove about 1" from the outside edge of the tire. Repeat this procedure twice more, in a groove in the middle of the tread, and in a groove 1" from the inside edge of the tire. If you can see the entire top of Washington's head in any of the 3 locations, that tire has less than 4/32nds tread remaining at that location, and it is time to replace your tires in the near future. They are not worn out now, but at 4/32nds tread, vehicles begin to take a significantly longer distance to stop on wet pavement; at 2/32nds, vehicles take about twice the distance to stop on wet pavement. Some articles recommend using a penny instead of a quarter to check tread deth, but the trick with Lincoln's head measures tread depth at 2/32nds, not the safer 4/32nds.
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Step 9
If your treadwear bars make a solid, flat line across your tires, replace your tires immediately.Next, if your tread depth test fails the quarter test, look closely at the tread depth on your tire. Every tire has been manufactured with treadwear bars embedded in them, to indicate the legal limits of remaining tread. Treadwear bars appear across the tread at even intervals around the tire. If you look closely at the sidewall, treadwear bar locations are marked with triangles at the edge of the crown on the sidewall. You can also insert your fingertip into any circumferential tread groove and follow the groove until your fingertip encounters a treadwear bar. Treadwear bars are 2/32nds tall, which indicates the minimum legal limit for tires that can be used on the street. If you examine your tire and see that the treadwear bar makes a solid flat line across the tread, replace your tires immediately. Your stopping distance will be double what it should be at this depth, and you are in danger of being ticketed for your tires should a law enforcement officer inspect them. If your tires are between 2/32 and 4/32 remaining tread, replace them in the very near future for safety and peace of mind.
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Step 10
Every tire manufactured for the past few decades feature a DOT code which includes the week and year of manufacture.Next, you should check the date your tires were manufactured. For the past few decades, every tire made has had to meet DOT standards and be stamped with a DOT code. This complete DOT code includes the manufacturing company, place of manufacture, and week and year of manufacture, and is stamped on one sidewall near the bead (where the tire seats against the wheel). It will be something like DOT AB CD 0000 (or 000). The DOT code may be mounted to the inside, which means it will not be visible to you during this inspection. If the DOT code on your tires isn't stamped on the outside sidewall, visit your local tire retailer and ask them to look at the DOT code for you for each of your tires. For some people, this is much more convenient than crawling under the car with a flashlight to find the DOT codes.
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Step 11
Finally, after you have located the DOT codes on your tires, you will need to assess the date. Tires made before 2000 are stamped with a 3-digit date for week and year of manufacture. Tires made after 2000 are stamped with a 4-digit date for week and year of manufacture. If you have a tire marked with a 3-digit date like 013 (for example), the tire was manufactured either the first week of 1983 or 1993. If your tire has a 4-digit date, the date of manufacture like 3604, your tires were manufactured the 36th week of 2004. Most tire manufacturers warranty their tires for 4 or 5 years after the date of manufacture. If your tires are 6 years old or more, you should take your vehicle to your local tire retailer and ask them to inspect your tires due to age. They should inspect them with the same process outlined here, but their experience may help them spot potential trouble spots in older tires that you may not notice. Generally speaking, tires that are 10-15 years old should be replaced ASAP, regardless of remaining tread, for safety and peace of mind.
