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Aug 29, 2019

How To Repair A Tire

It has happened to most of us. You're on your way to the store or driving home from work and you hit some sort of debris in the road, puncturing your tire, leaving you with a flat.

Although the tire is flat and must be brought to a tire repair shop, like Sullivan Tire and Auto Service, for an inspection, the tire may not necessarily need to be replaced. Depending on where the puncture is located along with the severity of the damage, the tire will either only need a simple repair or will be replaced. 

Sullivan Tire and Auto Service abides by the tire repair guidelines of the U.S. Tire Manufacturers Association (USTMA, formerly known as Rubber Manufacturers Association) and Tire Industry Association (TIA).

Repairable Tires

A tire can be repaired if:

  • It is punctured within the puncture repair area of the tire (pictured under the "non-repairable tire" section below)
    •  The sidewall and the shoulder of a tire cannot be repaired per TIA and USTMA guidelines
  • The puncture doesn’t measure more than 1/4 of an inch in diameter
  • The repairs do not overlap or if the injuries are not directly across from each other


Tire Repair Process

  1. Identify and Assess Damage
    • Remove the tire from the rim to thoroughly inspect both the inside and outside of the tire. Although a tire may appear to be a simple fix from the outside, the item that punctured your tire could have caused damage to the inner lining of the tire. This is why it's necessary to remove the tire from the rim or wheel.
  2. Prepare Repair Area
    • Once the tire is deemed repairable, remove the item that punctured the tire if necessary, and prepare the inner surface with a rubber buffer and/or pre-buffer cleaner. The are is then scraped to remove any type of debris.
  3. Remove Damages Cords and Stabilize Area
    • Using a carbide cutter on a low speed, drill into the puncture area starting from the inside of the tire, at least three times, to remove all the damaged cords and stabilize the area. Repeat this process starting from the outside of the tire, then vacuum any steel shavings or rubber dust left on the inside of the tire.
  4. Apply Vulcanizing Cement
    • Apply vulcanizing cement to the puncture area on the inner liner.
  5. Install Rubber Plug and Patch Combo
    • Plugging the hole from the inside out, pull the rubber repair plug (aka stem) end of the patch and plug combo through the puncture area. Cut the excess amount of the plig from the outside of the tire so it's flush with the tire tread.
  6. Stitch the Tire Patch
    • Using the stitcher tool, press firmly from the middle of the tire repair patch to the outside repeatedly to make sure there is no air trapped between the tire patch and the inner liner of the tire. Remove the plastic from the tire repair patch.
  7. Apply Liner Sealer
    • Apply inner liner sealer to the buffed area around the tire repair patch.
  8. Rebalance and Mount Tire
    • Mount the tire back on the rim, inflate to the proper air pressure, and rebalance the tire wheel assembly. The repair is then checked for air leaks before it is installed back on to your vehicle.

This procedure takes 60-90 minutes to be done properly.

Schedule Tire Repair


Non-Repairable Tires

In some cases, the tire can't be repaired due to the location or severity of the damage. If the tire meets any of the non-repairable guidelines below, it's time to buy a new tire.

Puncture Outside Repair Area

  • If the tire is punctured in any way outside of the Puncture Repair Area (see image), the tire cannot be repaired safely. 
  • True tire repairs are limited to the middle, or "crown" area of the tire.
  • The crown is defined as the center of the tread, approximately 1 to 1.5 inches in from each shoulder. For most tires, the puncture repair area can also be defined by the first major groove on both shoulders.
Puncture Repair Area on Tire Tread

Size of Puncture

  • The maximum repairable injury size for passenger and light truck tires through load range E is 1/4 inch, or 6mm in diameter.
  • If the puncture in your tire is larger than the allowable repair size, the tire must be taken out of service.
Steel Damaged Tire

Bulge or Bubble in Sidewall

  • If there is a noticeable bubble in the sidewall of the tire, it has been damaged most likely by impacting a curb, pothole, or other type of road hazards.
  • The resulting bulge or "bubble" in the sidewall is not repairable, and unfortunately, the tire must be taken out of service.
Tire Bulge Damage

Say "No" to Tire Plugs

A tire plug is a sticky, expandable object that gets pushed into the damaged area of the tire from the outside and is adjusted until the air is no longer leaking from the tire. Although the leak may stop, it is easy to believe that the tire is repaired and good to go; unfortunately, that's not the case. Tire plugs are a quick fix and can fail over time. They can also potentially cause air to become trapped between the layers of tread, eventually causing the tread to separate and result in needing to buy a new tire.

Industry Standards for Tire Repairs

The U.S. Tire Manufacturers Association (USTMA, formerly known as Rubber Manufacturers Association) and Tire Industry Association (TIA) standards:

USTMA Tire Repair Basics

  • Repairs cannot overlap. A rubber stem, or plug, must be applied to fill the puncture injury and a patch must be applied to seal the innerliner. A common repair unit is a one-piece combination unit with a stem and patch.
  • Not all tires can be repaired. Specific repair limits should be based on recommendations or repair policy of the tire manufacturer and/or type of tire service.
  • NEVER repair a tire that has an existing, improper repair; the tire must be scrapped.
  • A plug by itself or a patch by itself is an unacceptable repair.
  • NEVER perform an outside-in tire repair or on-the-wheel repair.

TIA Tire Repair Basics

  • The only way to properly repair a tire is to demount it from the rim so it can inspected on the inside, remove the damaged material, fill the void with rubber, and seal the innerliner with a repair unit.
  • A plug by itself or a patch by itself is not an acceptable repair because the plug does not permanently seal the innerliner and the patch does not fill the void left by the penetrating object, which allows water to enter the body of the tire and starting corroding the steel belts.
  • The use of sealants or emergency inflators that contain a sealant are not recommended as long-term solutions to a flat tire for the same reasons.
  • 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.
  • If the injuries are close enough so that the repairs overlap or the injuries are directly across from each other, the tire cannot be repaired and must be scrapped.
  • Never repair tires with a tread puncture larger that ¼-inch (6mm).