Whether it occurs during a tire’s first mile of use or after thousands of miles of driving, a single cut or puncture can make it necessary to replace a damaged tire that can’t be repaired.
The first consideration of evaluating if a tire can be repaired is based on how quickly the driver recognizes they have a problem and how promptly they respond to it.
Because tires require appropriate inflation pressure to carry the load of the vehicle, standard tires should never, ever be driven while low on air or flat (while run-flat tires offer extended mobility in the event of complete air loss, even they may not be suitable to return to service after being driven on while flat).
The telltale external sign of a tire that has been driven on while flat or very low on pressure is circumferential scuffing on the tire’s inboard and outboard sidewalls, but external inspection is not enough. Any repairs without removing the damaged tire from the wheel are improper because inspecting the inside of the tire for hidden damage greatly reduces the risk of returning a weakened tire to service. Without dismounting the tire, any hidden damage would likely be missed.
While the rubber doesn’t appear to have been severely damaged driving this tire for one mile when flat, the exterior abrasions confirm the sidewalls scuffed across the pavement due to the absence of air pressure allowing the tire’s reinforcing cords to fold under the weight of the vehicle.
Viewing the interior of the same tire reveals its innerliner has been destroyed and reinforcing cords have most likely been permanently weakened. The interior sidewall chafing against itself has caused the rubber to crumble into loose fragments. This tire must be replaced.
The second consideration when evaluating if a tire can be repaired is to confirm the size, type and location of the damage.
Industry guidelines allow repair of punctures of up to 1/4″ in diameter in a tire’s tread area. Some manufacturers limit the number of repairs permitted (usually two) and how close they can be (no closer than 16″ apart). Repair of any punctures in the shoulder and sidewall areas are not permitted.
This tire has been punctured in the tread area by a screw less than 1/4″ in diameter. If no internal damage is found when the tire is dismounted, this puncture can be repaired following industry guidelines and the tire returned to service.
This tire has been punctured through the shoulder area long enough ago for part of the nail head to have worn away. Since the puncture is outside the permitted repair area, this tire must be replaced.
Repair of larger tread punctures, long straight cuts and irregular gashes are not permitted. Long cuts have sliced through the tire’s steel belts, reducing strength and durability.
While this tire had only been in service for 24 hours, it ran over some accident debris that sliced through the tread, steel belts and body plies in an instant. The size of the jagged cut prevented repair to even be considered.
The interior inspection confirms the extent of the damage. The long cut would prevent the steel belts from providing the strength and durability needed for continued safe operation. This tire is beyond repair and must be replaced.
While having a flat tire is an inconvenience, returning a permanently weakened or incorrectly repaired tire to service (even as a spare tire) can ultimately have catastrophic results. If there is any doubt, replacing a questionable tire is far safer than repairing one.
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