Whether you're running late for work or adventuring far from home, flat tires always seem to come at the worst times.

Though they can be inconvenient, the good thing about flat tires is you can often get tire repair service instead of replacing them. Considering a new tire can cost $50-$150, and a flat repair normally runs $5-$40, there are significant savings in opting for tire repair instead of replacement.

To help you better understand the tire repair process, we've outlined the main ways you can fix a punctured tire, their pros and cons, the tires you can't repair, and issues that may cause a flat tire. 

Tire Repair Options

There are several tire repair options when you run over a nail or other debris that punctures your tire. While all these repairs will reseal the tire, they aren't equal in quality, safety, and longevity. 

Tire Sealant 

Tire sealant is the simplest flat repair method. It involves injecting a pressurized sealing chemical through the valve stem — just like inflating your tires — and letting the sealer fill the puncture. Some sealers even have enough pressure in the can to inflate the tire too. 

There are also tire repair kits, which include a sealant, a portable inflator, and other useful tire repair tools. Some new cars even include these kits in place of a spare tire. 

Tire sealants are for emergency use only, and you should never consider it a permanent repair. After sealing the tire, immediately drive to a repair facility to have the tire inspected and properly repaired or replaced. 

When you get to the shop, make sure to warn the technician that there's sealant in the tire. Without this warning, the technician could end up with a massive mess of sealant on the floor. 

Tire Plug

A tire plug is another basic flat tire repair method. The Plug is essentially a piece of string coated in unvulcanised rubber. 

To install a tire plug, you remove the item from the tire that caused the puncture, then ream the hole to smooth out the hole and widen it slightly. You then place the string in the plug tool — a large, needle-like tool — and press it through the hole. Finally, pull the plug tool out slightly — just enough to free it from the plug — and remove the tool from the plug, leaving the plug behind. 

Once you drive the vehicle, the heat will vulcanise the rubber and seal the hole. 

A tire plug has a few benefits. First, it's a quick repair that doesn't require dismounting the tires from the wheels. It's also generally less expensive, and you can do it yourself in a pinch. 

However, a tire plug is not a permanent repair. Plugs are designed for temporary use only because they have a tendency to leak and can slowly work their way out of the hole at high speeds. Also, plugs can allow water to seep in and cause the wheels and the steel bands that hold the tire in place to rust. 

Tire Patch

An internal tire patch is another way some auto repair shops fix flat tires. 

To complete a tire patch, the technician must remove the tire from the wheel and carefully use a grinder to remove any burrs or stray steel belts, and to create a rough surface for the patch to adhere to. The technician then glues the patch over the puncture, uses a small roller tool to smooth it out, and applies a patch sealer. Due to the tire patch's self-vulcanising properties, it will permanently affix to the tire once it heats up from normal driving. 

A tire patch is superior to a plug because there's no risk of it flying out at high speeds. Plus, it creates a more reliable seal because it covers the hole and its surrounding area. 

However, patches are generally more expensive because they are more time-consuming and require the technician to balance the tire. A standard patch also doesn't fill the puncture, leaving the potential for leaking down the road. 

Tire Patch-Plug

A tire patch-plug is most tire manufacturers' preferred way to repair punctures. A patch-plug is a small, round, rubber patch with a mushroom-like plug mounted in the center. This allows the technician to plug the hole and patch the surrounding area, creating the most reliable repair. 

A patch-plug goes on similar to a patch, but the technician may need to drill the puncture to widen it so the plug fits through. The technician then glues the patch-plug into place and pulls the plug outward from the outside of the tire to ensure a good seal.

Once the tire is mounted and inflated, the technician will cut the plug's length to match the tire's tread depth.

The key benefit to a patch-plug is it offers the most secure, longest-lasting repair. When done correctly, a patch-plug will last the life of the tire with no leakage. 

The downside is it's a time-consuming process and among the most expensive puncture repairs. 

Limitations of Tire Repair

Not every tire puncture is repairable — patches and plugs have their structural limitations. Here are some cases where the tire is simply unrepairable. 

Large Punctures

Regardless of the type of tire repair service you choose — plug, patch, or patch-plug — the maximum diameter puncture you can safely repair is 6 mm. Anything larger risks leakage, which can result in more serious issues down the road. 

Punctures on the Shoulder

All tires have two main tread sections. The tire's contact patch is the centermost portion of the tread between the outer tread channels — the circumferential grooves in the tires. The tire's shoulder is the area between the outermost channels and each sidewall. 

The tire shoulders not only endure a lot of stress, they also have a slight curve to them, making them unsuitable for patches or plugs. If your puncture is in the shoulder, the tire is not repairable, making your only option a new tire. 

Punctures on the Sidewall

The tire's sidewall — the vertical face on each side of the tire — is not rigid enough to support a plug or patch. This section bends and flexes to enhance ride comfort and handling, but this flexing will cause any patch or plug to become detached. 

For this reason, sidewall punctures are not repairable. 

Tires With Insufficient Tread Depth

While you can repair a tire with just about any tread depth, liability is an issue most automotive shops take seriously. If they repair a tire with under 1.6 mm of tread depth, and your tire blows out the next day due to its low tread, the repair shop may be held liable. 

So, many auto service facilities will recommend a new tire in these instances. 

Special-Use Tires

While a tire patch is perfectly fine in most tires, even winter tires and tires with high speed ratings, specialty use tires aren't repairable. These would include dedicated racing tires or drag slicks. 

Other Causes of Flat Tire 

Punctures are the most common reason for flat tires, but they're far from the only reason. Here are some other causes and how to rectify them. 

Tire Pressure Monitoring System Sensor Leak

Tire pressure monitoring systems aren't mandatory in Canada yet, but it's common to see them on vehicles. These systems often use a sensor inside each tire that connects to the valve stem and detects the tire pressure. 

Over time, the O-rings on these sensors and their valve stems can fail, resulting in a leak. A technician can fix this by removing the tire and sensor, installing new O-rings, and reinstalling the sensor and tire. 

Valve Stem Leak

The rubber valve stem — the rubber stalk you fill your tires through — deteriorates over time or can be damaged, resulting in a leak. A tire service technician can fix this by removing your tire, installing a new valve stem, and reinstalling the tire. 

Wheel Damage

Occasionally, you can hit a pothole too hard or run into a curb and bend or crack the wheel, starting a leak. In some cases, a wheel specialist may be able to fix the issue. Usually, a new or a good used wheel is the best solution. 

Clutch Won't Leave You Flat

When buying a pre-owned vehicle, it's important to get one with quality tires to ensure your vehicle remains in top shape for years to come. At Clutch, Canada's first 100% online car-buying experience, all our vehicles go through a 210-point inspection and a reconditioning process that includes checking the tires and replacing them if needed. We replace all tires with under 4mm of tread depth, far exceeding the legal limit of 1.5mm.

For added peace of mind, we also offer the Clutch Protection Plan. This plan not only covers all your vehicle's major mechanical and electrical components, it also includes unlimited-kilometre tire and rim coverage. This coverage includes flat repairs, tire replacement, and more at no cost to you — not even a deductible. 

Ready to experience Clutch? Check out our online pre-owned inventory, choose a vehicle that suits your needs, and have it delivered. You can even trade in your old car online when you buy your new one from Clutch.