The quarter-inch rule This is very simple: never repair a tire with a puncture greater than a quarter inch or 6 mm in diameter. Also, never repair any punctures found on the tire sidewall. Puncture repair is limited to the tread area and only between the outside shoulder grooves.
Puncture repairs are limited to the center of the tread area. If there are punctures or damage in the shoulder or sidewall of the tire, it is not repairable.
The patch won't hold - Tires have cords that run all around the tread of the tire, the part the makes contact with the road. But on the sidewall, those cords aren't there. So, there's just no way for a plug to fill that hole. The patch won't hold, and it's going to continue to leak.
So if you end up with a damaged tread, you can plug and patch away, but if the damage is to your sidewall, you're going to have to replace the tire, which usually means replacing the fronts or rears in pairs. So can you patch the sidewall of a tire? The answer is a solid no.
In general, a hole in a tire must be less than one inch in diameter in order to be patched; however, the location of the hole must be on the tread of the tire at least 1/4″ away from the sidewall in order to be patched. A tire can generally only be patched three times.
For a safe repair, the puncture must be 1/2 inch away or more from the edge of the tire tread where the internal steel belt begins. Any puncture less than 1/2 inch from the start of the internal steel belt on the shoulder or sidewall of the tire cannot be repaired (highlighted in red).
Typically, the damage must be in the middle part of the tread for a tire to accept a plug. If there is an inch or more from the edge of the tire, there's a good chance you can plug it. However, you'll need to invest in a new tire if the damage is outside this narrow area.
Repairable Area
However, some manufacturers actually let you patch punctures within that region, as it depends on the internal design of the tire. Again, the punctures shouldn't be close to the sidewall, with ¼ inches (6 mm) the closest you can go.
The typical way that a tire is fixed, and it's completely improper, is to take a plug and just jam it through the tread of the tire and that's the end of it. If it doesn't leak, everything is fine.
So, make sure you know that: If the puncture is in the safe zone, you can apply the traditional patch as a temporary fix. However, if the patch is too close and goes below the 6 mm distance from the sidewall, there's no option but to replace the tire completely.
If you have a choice between patching or plugging your tire, most experts recommend patching because it provides a stronger, longer-lasting repair. However, both methods can be effective ways to fix a flat tire if done properly.
If you have onboard air, we recommend removing the valve core or waiting until the tire is completely deflated before installing the plugs so there is less resistance.
One can double plug a tire if the punctures are smaller than a quarter of an inch or 6 mm in diameter and at least 16 inches apart. It is not a good idea to replug a plugged tire twice in the same place, or when the puncture is near the previous slit or leakage.
A tyre can only be repaired if it is a small puncture (less than 6mm in diameter) in the central ¾ of the tyre, anywhere else is deemed unsafe as it is too close to the sidewall. Other factors to take into consideration are what the tyre was punctured with and the general condition of the tyre.
TIRE SHOULDER. The outer edge of the tread that wraps into the sidewall area.
In my experience, a chipped sidewall rubber that's just a few millimeters deep is repairable, but anything deeper than that is not. And the main issue here is that deeper cuts damage the inner cords, which can significantly weaken the tire's construction and lead to blowouts.
“For everyday street-use tires an 80 millimeter sidewall height is our threshold,” says Mark Ludlow, a tire engineer for Michelin. “Anything under that size is built only for racing or show cars. But we feel any sidewall that falls under 65 millimeters is more about show than go,” he says.
Sidewall cracks aren't completely out of the ordinary, and small cracks that are barely visible aren't likely to represent an imminent safety concern. If sidewall cracks continue to grow in length, depth, or number, you may want to consider replacing your tires.
The use of a standard puncture repair unit in the shoulder (S-T) area will result in the repair unit being exposed to more stress in the upper sidewall, due to the characteristics of the tire. This could potentially result in a premature repair failure.
Simply push the installer into the hole in the tire until the plug is about 3/4 of the way in. Twist the installer tool 90-degrees and pull it out. The plug will stay in the tire and the tool will come out nice and easy. You may trim away the excess plug or leave it to wear away as you drive.
Can I drive long distance with a plugged tire? Yes, when repaired correctly, driving long distance on a plugged tire is safe. Tire plugs are a quick fix that can last up to 25,000 miles. However, if the plug is at the outer edge close to the sidewall, it's a temporary fix not safe for long distances.
The sidewall is the most fragile part of the tire. Compared to the tread, the sidewall is not only thinner, but also has insufficient steel wire to adhere, so it is more fragile.
Your tire has very useful information molded into the sidewall. It shows the name of the tire, its size, whether it is tubeless or tube type, the maximum load and maximum inflation, the important safety warning and much other information.