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So you have noticed a hole in the side wall of your tire and wondering if you can plug it. It’s a reasonable question because tires, especially if you have only replaced them recently, are expensive.

Below we will look at the safety implications of plugging a tire in your sidewall and what the experts say.

If you look on forums, you may come across people saying they have successfully plugged the sidewall of their tire. You will also come across experts and trade bodies saying this should not be done.

 It’s difficult to know who to believe. On one side, other road users say they have successfully plugged a side wall. 

On the other side, you have tire trade bodies potentially interested in getting you to replace tires, saying it is not safe to plug.

The Anatomy of A Tire Sidewall

If you look at the diagram below and pay particular attention to the side of the tire, you will see that apart from the body ply, there is nothing else underneath the rubber on the side wall.

Radial Tire Showing Belts and Ply
Note the lack of support for the sidewall

The tread section has steel belts and additional nylon ply. These structures underneath the tread provide additional stability to that section. Because of this additional strengthening, plugging the center section of the tread is safe. 

Plugging the sidewall, however, is not. Once the side wall is penetrated and leaking, it has lost its structural integrity.   There is no steel belt or ply to strengthen the section.  

It relies solely on air pressure to keep it solid and stable. 

There are no ply or steel belts in the sidewall because its job is to flex when you go over potholes or uneven road surfaces. 

Sidewalls are load bearing; if you have a plug in the sidewall and the sidewall flexes, it will put the plug under immense strain.

When you hit a large hole, your tire becomes slightly compacted, raising its air pressure not by much but enough to allow air to find weak points in the tire and force its way through. 

Blowouts are usually because of sidewall damage and not tread. 

Will Some Tire Shops Plug A Sidewall?

It’s extremely unlikely you will find a professional tire shop willing to plug a sidewall.  

You could find one that will, but they will not be a professional outfit, will not hold any indemnity insurance, and if they are willing to plug a sidewall, have very little knowledge on basic tire fitting and safety. 

You should stay well away.

tire shop repair tires
No reputable tire shop will plug a sidewall

Tire Expert’s Views On Plugging Sidewalls

The Rubber Manufacturers Association (RMA), as it used to be before it became the US Tire Manufacturers Association (USTMA), states that approximately 88% of all tire repairs are done incorrectly. 

That is a massive percentage. You can be sure that many will be incorrect sidewall repairs done at home by people trying to save money. 

“Repairs to the shoulders or sidewalls, other than for cosmetic damage, may not assure the structural integrity of the tire and are not approved.” 

British Tire Manufacturers’ Association 

The Tire Industry Association writes on its website:

“Many times, a simple object such as a nail in the tread can result in severe damage to the sidewall that cannot be seen on the outside of the tire. Therefore, on-the-wheel wheel repairs like string plugs are not recommended and must be considered temporary.”

Is It Legal To Plug A Tire Sidewall?

There appears to be no specific law preventing anyone from plugging their side wall. But that doesn’t mean it is perfectly legal to do so.

A search on state and national legislative websites does not specify that tire sidewalls should not be plugged.

However, all of them state that a car should be kept in a roadworthy condition and maintained in line with the manufacturer’s guidance.

“There is a move by the RMA to legislate what would be an “improper repair,” but so far this has not passed in any State legislative session.”

Laws Regulating Tire Repair in the United States

All tire manufacturers state on their websites that tires with sidewall damage are irreparable and that a new tire is needed. 

So plugging tires on the sidewall does not appear illegal, although you should research it as laws often change over the years. 

So although it isn’t illegal, driving with a plugged sidewall is clearly unsafe.

Because all the tire manufacturers and trade bodies say this if you were involved in an accident and caused someone serious injury or death, you could be liable for a lawsuit from that person or the deceased’s family members. 

As already mentioned, sidewall repairs often blow out, and you will not know when or where this will happen. It is not worth the risk of hurting someone for the sake of $100 or so.

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