Why Can’t You Plug A Tire Sidewall? [ANSWERED]

It can be really frustrating to have a perfectly good tire ruined by damage to the sidewall. You may have been told that the tire sidewall can’t be plugged and that you must buy a replacement.

What makes a damaged sidewall so bad and a plug repair impossible?  

In this article, we will examine the reasons and the structure of a tire to explain why this is so.

The image below shows a cross section of a tire. As you will see, there is nothing in the sidewall section to strengthen the rubber compared to the tread section that has cord and steel belts to support the tread.

This is because the sidewall needs to flex when it goes over bumps. If there were additional cords and steel in this side wall section, it wouldn’t be able to. 

A plug must be supported by the steel belts and the cord underneath the tread area to ensure a good seal. 

The only thing maintaining the structure of the sidewall is the air pressure forcing it outwards against the bead. Any damage will cause the sidewall to blow out.

Tire blowouts are more common in the sidewall section of a tire than the tread area because there is no other support here. 

The Rubber Manufacturers Association (RMA) states that approximately 88% of all tire repairs are done incorrectly. 

You can be sure that a fair percentage of this figure is from people that have decided to plug the sidewall at home using a kit they have bought from the internet. 

Although the below quote is from the British Tire Manufacturers Association website, you can be sure the advice in this global business applies worldwide.

“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 

What Is Cosmetic Sidewall Damage?

And here lies the problem there is no real definition of what cosmetic sidewall damage is. Is it left to interpretation? 

Here is the legal definition of cosmetic damage: 

“Cosmetic damage” means superficial blemishes or defects that do not interfere with the functionality of the component or system. 

NORTH CAROLINA GENERAL STATUTES

A brief look on the internet at different state statutes has very similar wording. But still, the word cosmetic is open to interpretation. 

It is difficult for someone not experienced in repairing and replacing tires to know what superficial means and what is defective. 

Is A Nail In A Sidewall Fixable?

A nail in a side wall is not fixable unless it is superficial and cosmetic.

Of course, each case should be taken on its merits, but it’s always worth taking your tire to a tire shop to see if the nail damage is deemed cosmetic or not.

Generally, a very small nail that has caused very little impact to the tire sidewall might be ok but should still be checked.

How To Repair Tire Sidewall Puncture Leak

A tire wall puncture leak cannot be repaired, but if you mean the bead is leaking attached to the sidewall’s edge, then the best way to repair this is to remove the rim and tire and clean up the lip of the rim.

Then remount the tire and use tire sealant between the rim and the tire bead. They should provide a permanent leak fix if the rim isn’t bent. 

Where Can You Plug A Tire Sidewall?

No reputable tire shop will plug a tire sidewall. Of course, nothing is stopping you from doing this yourself at home, but you should be aware that doing so could cause you problems in the future.

Firstly most car insurance policies have clauses that state you must keep your car in a roadworthy condition.

If you have plugged the sidewall of your tire against the tire manufacturer’s advice, you may not be following this clause and, therefore, could be driving around in an uninsured vehicle.

If the tire was to blow out and you were to injure someone due to a collision caused by a plugged sidewall, you may find yourself the subject of a negligence claim by the injured third party. 

Can You Patch The Sidewall Of A Tire?

All tire patches are fixed on the inside of a tire; therefore, the rim or wheel needs to be removed to effect a repair.

Tire patches are the best repairs and are far better than plugs; however, like plugs, you cannot patch a tire sidewall.

Is It Safe To Patch A Car Sidewall Tire?

Never patch or plug a tire sidewall. This goes against the manufacturer’s advice, and no tire shop would entertain doing this for you.

It isn’t safe because it increases the risk of a blowout. A blowout can happen at high speed and cause you to lose control of your vehicle and cause a severe accident. 

Conclusion

You can’t plug a sidewall because this area has no steel belts or cords that reinforce the area as tire tread has.

The sidewall relies solely on air pressure to maintain its structure. Any hole in the sidewall means this has weakened the area, and the tire is prone to blowing out.

No tire shop will repair sidewall damage, and you will need to replace your tire with a new one.