When to replace car tires?

Many questions arise related to tires, such as when to replace car tires? Do you have to replace a car tire? How old is the car tire that is safe to use? What are the signs that we must replace a tire? And other similar questions that often arise among vehicle owners.

Of course, all of these questions are closely related to safety when driving. Yes, tires breaking while driving can be very frightening for every driver and even the car owner. Especially when the car is driving at high speed, the risk of traffic accidents is very high and difficult to avoid.

By knowing the signs when we should replace the tires, we can minimize the situation to eliminate concerns about tire breaks during driving. So here they are, signs to replace car tires.

1. Minimum tire tread depth reaches its limit

The first time to know when to replace car tires is from the tire tread depth. Tire Tread depth is a vertical measurement from the top of the tire's rubber to the bottom of the tire's deepest grooves. Tire tread depth ensures stable handling and the ability of the tire to grip the road surface when conditions are wet or snowy.

To gauge tread depth, all you need is a Lincoln penny. Put Lincoln's head into one of the big grooves. If the top of his head is flush with the tread, you have some grip remaining for rainy or snowy conditions.

It would be best if you considered replacing your tires when they reach approximately 4/32" of remaining tread depth. Or, if you can see space above Lincoln's head, you may need to replace your tires immediately.

If you don't have a Lincoln penny, you can see tire tread depth from the tire tread wear indicator (TWI). This indicator is marked with triangles in the tire sidewall. If you draw a straight line towards the tire surface from the triangle mark, you will find the tire tread protruding slightly from the bottom of the groove.

If the thickness of the tire tread has touched the mark, then it is time for you to change your car tire.

2. Tires have been used for more than six years

The second time to know when to replace car tires is from tires age that calculate as tire expiration date. Maximum tires usage can reach about ten years, but six (6) years are the most common car tire usage. Every tire has a birth date (the day it was manufactured) and an expiration date six years from that manufacture date.

You can see the DOT code outside of tires as tire expiration date. The important code is the last four digits number. The last two digits refer to the year produced, and the first two digits identify the week number within that year. See the example images below.

From the images above, we can see that the tire was produced in the 35th week of the year 2017. So, if the tire is in regular use, the tire should be replaced after 2023. Even if they appear in usable condition and have not worn down to the tread wear indicator, the tires must be replaced after ten years. Tire expiration date is calculated from their date of manufacture.

3. There were some tire damages

Another sign to replace car tires is if there were some tire damages. The form of tire damage is very diverse. Below are some tire defects that consider replacing the tire immediately:

Uneven tread wear
Shallow tread
Flat tire
Bulge sidewall
Cracked tread

Some damage such as uneven tread wear and shallow still can minimize your cost, such as tire rotation. Still, flat tire and bulge sidewall is not recommended to use longer. Bulge sidewall damage and a flat tire are risky because the inner components of the tire were damaged and broken, so the tire can blow up suddenly while driving.

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4. The tire has been patched too much

The last signs to replace car tires if they are patched too much. Theoretically, you can patch a tire until there is no more room to put a patch. The industry rule of thumb is no more than one patch per 1/3 of the tire.

But, each time you patch it, it becomes less reliable. Each hole is mechanical damage to the tire that is not repaired by the patch. So, if the tire is patched too much or patched on the tire's sidewall, it's better to replace the tire with the new one.