How to Fix Cracked Tires – And How to Know if They Need Replacing?

When is someone going to invent tires that don’t suffer from wear and tear?

They play a crucial part in how much control you have over your car. Unfortunately, there is a collection of complications that can affect them. One of the most insidious of these is dry rot. You may recognize this more as yours start to crack.

In this article, we list the causes, symptoms and preventative measures against dry rot, and how to fix cracked tires.

Gloved mechanic hand inspecting a car tire on a black wheel

Below you will find out when the symptoms are too advanced and a tire needs replacing, and when a repair is possible. If it hasn’t escalated too far, we advise on how to fix them internally and externally.

Those of you who want to go to a professional will learn what to anticipate.

And perhaps most importantly, this article will tell you when it’s safe to drive with cracked tires and when it isn’t.

What is Dry Rot/Tire Cracking?

Don’t confuse the dry rot we discuss here with the fungal disease that targets plants and wood. Thankfully, tires aren’t susceptible to this kind of problem. If they were, those of you who live in coastal areas would be buying a new set every few months.

The name comes from the appearance of the unit as it degrades, which can resemble real dry rot. It’s the breakdown of the materials over time.

Various materials go into producing modern tires. Besides natural and synthetic rubber compounds, there are also property-boosting additives. For instance, black carbon is used for reinforcement. Protective waxes and oils are applied during the final stages of the process.

Very little of an average tire is made of pure, natural rubber. Not only would that lead to high costs, but synthetics tend to be more durable.

Still, they aren’t invincible: whoever invents an everlasting tire would make a fortune. They’re susceptible to degeneration like everything else in your car. This manifests over time with distinct physical symptoms, which we cover below.

What are the Early Signs of Dry Rot/Tire Cracking?

The early signs below don’t happen instantaneously. It takes time for the degradation to start to appear. They could be rotting right now, and you won’t be able to tell by inspecting them.

This is one of the many reasons why preventative care is beneficial: stopping dry rot while it’s still in the invisible stage.

Look out for the following three indicators:

  • Cracks on the tire sidewall.
  • Brittle, dry rubber.
  • Minor flaking or peeling.

Cracks on Sidewall

Cracks appearing on your sidewall are a telltale warning of early-stage dry rot. You may see a few in one area, or they may have fully surrounded your hubcap.

Brittle, Dry Rubber

Healthy rubber is flexible; that’s what makes it ideal for driving on. It compensates for changes in the road and the shifting weight of your vehicle.

When dry rot takes hold, the protective waxes and oils we talked about earlier will start to wear away. As a result, they’ll look dried out or feel brittle to the touch.

Minor Flaking or Peeling

Small pieces flake off around heavily affected areas. Think of mildly dehydrated skin.

What are the Causes of Dry Rot/Tire Cracking?

Numerous factors provoke cracking, such as:

  • Extreme temperatures and high humidity.
  • Long periods of disuse.
  • Poor maintenance.
  • Low-quality materials.
  • Natural aging.
  • Exposure to ozone.

Extreme Temperatures and High Humidity

Temperatures at either extreme aren’t good for rubber. At freezing or below, the material is prone to turning rigid as it dries out.

During boiling hot summers they can suffer from heat-fatigue. Strong UV light speeds up or triggers dry rot.

The rays of the sun fade, crack and break down the chemical bonds in rubber compounds. Waxes and oils gradually evaporate, leaving them even more vulnerable.

Long Periods of Disuse

Leaving your vehicle parked for months on end won’t preserve your tires. On the contrary, long-term disuse is a direct cause of dry rot.

When the tire isn’t moving, useful compounds such as antioxidants and oils aren’t being distributed. Instead, they either evaporate or leech into the concrete.

Poor Maintenance

When your mechanic emphasizes following up with maintenance, it’s not a gimmick. Regular services are vital to keeping your car running safely and smoothly. Neglecting your tires is a sure-fire way to amplify your chances of seeing cracks.

Low-Quality Materials

Financial limitations make it difficult to pay the price for OEM units. You may have to settle for a less costly model or set. If that’s the case, take care when you’re shopping. You can conserve your money without having to sacrifice on quality.

Be wary of online distributors selling units that are dramatically cheaper than reputable businesses. Your purchase may look perfect on the outside, but be poorly built.

Natural Ageing

Cracking signals that they’ve been on your vehicle for too long. Thousands of miles and years of exposure to the elements are inevitable causes of aging.

Exposure to Ozone

Ozone is fine way up in the earth’s atmosphere, but not so great for tires. At ground level, it’s a pollutant.

Aerosol sprays and electrical appliances produce ozone. Air purifiers or laundry water treatment systems that you may keep in your garage where your vehicle is emit it.

Apart from ozone being a respiratory hazard and unhealthy for plants, it also negatively impacts inanimate objects. This includes fabrics, wires, and rubber.

When do Tires Typically Dry Rot? How Long do They Last Before Dry Rotting?

As discussed, many variables determine when (and if) dry rot strikes. The older the unit gets, the more likely it is to start to degrade.

A carelessly maintained tire that’s two years old could look worse than one that’s four years old but well looked after.

The same will likely apply if the newer model is subject to any of the conditions we described above.

How Does Dry Rot Affect a Vehicle’s Tires?

Is it safe to keep driving with cracked tires, and if so, for how long?

Dry rot isn’t necessarily always an urgent matter, but it can be. Before you continue rolling with your current tires, you should know about these effects:

  • Reduced handling and control.
  • Increased likelihood of punctures, flats or blow-outs.
  • Rotted sections may fall off while driving.

Reduced Handling and Control

Steering systems and differentials don’t count for much if your tires are failing. Cracking is a sign of failure.

As the damage progresses, it will jeopardize the integrity of the unit. If large sections of the unit are affected, it won’t handle as well.

Increased Likelihood of Punctures, Flats or Blow-Outs

Tires are subject to immense pressure while your car is in motion. They also get hotter the longer you drive, and the faster you go.

Cracks are weak spots that won’t hold up well to the strain. Particularly if cracks are in the treads, running over a sharp object could cause a puncture.

The worst outcome would be a blow-out. This may be the result of a puncture or one or more cracks tearing open under stress.

Understand that any problem with your tires raises your accident risk. Adding to that unsettling statistic, more cars with these issues rolled over than not.

Rotted Sections Can Fall Off While Driving

Insisting to drive on severely rotted units can endanger other road users, not just you and your passengers.

Large portions of the unit can begin to rot and separate. If a large piece falls off, it could end with an explosive blow-out. That big chunk of rubber in the road will then pose a risk to anyone driving behind you.

And it isn’t easy to remove debris like that from busy roads like highways or in city centers. You don’t want to be liable for other individuals getting hurt.

Is it Safe to Drive With Cracked Tires?

After the last section, you’re probably expecting a resounding, “no.” But, if you catch the dry rot at the early stages and repair it, you should be in the clear. Afterward, it should be safe to continue driving on it.

This is assuming there aren’t any other problems. If you’ve had it on your vehicle for too long or the treads are worn flat, dry rot is the least of your worries.

Driving with moderate to advanced dry rot means gambling with all the consequences mentioned above.

Are Your Tires Too Far Gone? Inspect Them First

Before you go any further, inspect them first. It could be that the dry rot is beyond the point of fixing.

Be sure to rotate your wheels as you examine them, or have an assistant do so. Hopefully, the cracking isn’t too serious yet.

We don’t advise attempting to conduct a repair if you notice:

  • Severe cracks on the sidewall.
  • Discolored rubber.
  • Nonexistent or cracking treads.
  • The unit is falling apart.

Severe Cracks on Sidewall

A few hair-thin cracks aren’t alarming. If they’re deep, thick or widespread, resign that unit to be recycled.

It doesn’t matter that your sidewalls aren’t in direct contact with the road. These badly-rotted areas can break apart from heat and pressure.

Discolored Rubber

Carbon contributes to a tire’s durability. It significantly lowers the effects of abrasion and overall wear.

Areas that are fading or discolored are losing this compound, which doesn’t bode well for resilience.

Nonexistent or Cracking Treads

How well your car grips the road (traction) and its stopping power are related to the state of your treads. Cracks will decrease these abilities, meaning driving will be a lot more dangerous.

If you can barely see the tread pattern anymore, the units are bare—from age or hard use. There’s no miracle product or solution to restore them.

Falling Apart

A little bit of flaking rubber due to brittleness is acceptable if it’s just a small amount. If any floppy sections are hanging off, it’s finished.

Fixing Dry Rot Inside and Out

We suggest performing both internal and external repairs for maximum effectiveness. Using just one method won’t be as successful.

Remember to check them periodically; at least once a month. If dry rot reappears, replacement might be your only option.

How to Fix Cracked Tires Internally Using Sealant

Sealants are substances that are applied internally. These are used as a preventative or in the event of a flat.

Choose one that specifically mentions cracks or dry rot. Stop-flat varieties aren’t appropriate and won’t do any good.

Make sure the brand you buy is suitable for your tires. For instance, some are for larger vehicles, whereas others are only suited for lightweight ones.

Equipment needed:

Never used one of these products? Don’t worry; there’s nothing difficult about the process. This is all you need to do:

  1. Let your car cool down.
  2. Remove the stem valve.
  3. Prepare sealant (if needed).
  4. Apply sealant.
  5. Reinflate tire.
  6. Drive to circulate.

Step 1: Let Car Cool Down

If you’ve recently driven it, give the whole vehicle time to cool off. The tire you’re treating should feel cold to the touch.

Step 2: Prepare Sealant (If Needed)

Your product may have come as a kit with a hose. If it’s in a can, you might have to agitate it before using it.

Get the sealant ready as specified by the manufacturer guidelines.

Step 3: Remove Stem Valve Cap

Unscrew the stem valve cap and put it aside.

Step 4: Apply Sealant

Insert the injector or nozzle into the valve stem. Squeeze or spray in the directed amount of sealant.

Step 5: Reinflate Tire

You likely lost some air pressure while you performed the treatment. Reinflate as needed, checking the PSI with your pressure gauge. Close the stem valve with the cap.

Step 6: Drive to Circulate

Take your car out for a ride so that the product coats the whole inside of the tire. This might not be required for some sealants.

How to Fix Cracked Tires Externally Using Protectant

A protectant is the external version of a sealant. These coatings rejuvenate the rubber as well as shield against threats like UV light.

Choose a water-based brand over a solvent-based one. Solvents are volatile agents, meaning they can be toxic if handled.

Equipment Needed:

  • Gloves.
  • Tire protectant.
  • Tire-safe degreaser.
  • Large drain pan.
  • A good floor Jack and jack stands.
  • Lug wrench.
  • Access to a hose or water source.
  • Sponge and clean rags.
  • Empty jugs or containers.

We’ll be honest: this fix is going to take more time than the internal method. Set aside an hour or two and work through these steps:

  1. Set up a suitable work area.
  2. Let your vehicle cool down.
  3. Jack the car up and put your gloves on.
  4. Remove cracked units.
  5. Place tire in your drain pan.
  6. Coat with the degreaser.
  7. Let it sit, then scrub.
  8. Rinse it thoroughly.
  9. Wipe it down and let it air-dry.
  10. Empty drain pan contents.
  11. Apply protectant.
  12. Refit it.
  13. Repeat with all affected units.

Step 1: Set up a Suitable Work Area

This is going to be a messy job. Imagine how filthy your tires are after rolling on the road for thousands of miles.

You need a flat area to work where your drain pan won’t be at an angle. You don’t want runoff to pollute the environment or stains on or near your property.

Step 2: Let Your Vehicle Cool Down

Wait until none of the tires are warm or hot to the touch. If you haven’t been driving, start straight away.

Step 3: Jack Car up and Put Gloves On

Jack your car up and place your jack stands to keep it secure. Put your gloves on to be able to handle your tires.

Step 4: Remove Cracked Tires

A thorough cleaning is impossible while they’re still attached to your rims. Remove each one that’s showing early symptoms of dry rot. Prop them up and set them to the side.

Step 5: Place Into Drain Pan

Place the first tire into the drain pan.

Step 6: Coat With Degreaser

Apply your tire degreaser as instructed on the label. You may have to spray it on or use a

sponge to apply it.

Make sure the product gets into all areas. A layer of dirt will interfere with the protectant, so make sure they are clean first.

Step 7: Let Sit, Then Scrub

Give the degreaser a few minutes to take action. Then, start scrubbing with your sponge.

Pay special attention to the areas that are beginning to show cracks. Take your time to

loosen stubborn road grime.

Step 8: Rinse Thoroughly

Set your hose to low pressure so that you don’t blast degreaser and filth everywhere. Gently rinse the entire surface of the tire, using a few rags for assistance.

Don’t stop rinsing until the rags are coming back clean. You may have to lift it out of the drain pan to reach the entire surface area.

Depending on the drain pan’s size, you may need to empty it. Transfer the contaminated water into your containers.

Step 9: Wipe it Down and Air-Dry

With fresh rags, wipe it down and set it on the ground to air-dry.

Step 10: Empty Drain Pan Contents

Pour any remaining dirty water into your containers to be disposed of later. Wipe the

pan down or rinse it out.

Step 11: Apply Protectant

Spray or wipe on your protectant all over the tire surface as instructed. Distribute it all over the tire, not just on the cracked areas.

Step 12: Time to Refit

Once the protectant has cured, put the tire back onto your car.

Step 13: Repeat as Necessary

Repeat the above steps with all the cracked tires.

Going to a Professional to Fix Cracked Tires: What to Expect

Your mechanic will likely err on the side of caution and suggest a replacement. A detailing shop may agree to use protectant if the units aren’t too far gone.

This will probably be as part of a package (e.g., buffing, polishing, etc.). Not many businesses will agree to detail your tires alone as it isn’t worth their time.

How to Prevent Dry Rot

There’s no way around it: any aging rubber will become prone to cracking. You can’t shield your units from this fate, but you can lessen the chances of dry rot with our tips:

  • Practice good maintenance.
  • Don’t forget to use your car.
  • Park inside your garage or buy a car cover.
  • Keep your vehicle away from ozone-producers.

Practice Good Maintenance

Schedule services within intervals suggested by your vehicle’s manufacturer. Rotations are usually every 5,000 to 8,000 miles; pressure checks should be done once a month.

Have your mechanic examine each tire for damage every year. Or, do it yourself if you know what to look for. This includes bulging, irregular wear, physical damage, and odd noises.

Don’t Forget to Use Your Car

Do you have a vehicle that you rarely use? Make a point not to let it sit on the tires for months without movement. Drive it once or twice per month helps to keep them in good shape.

If this isn’t possible, prepare your vehicle for long-term storage. Remove the tires, wrap them up, and set your car on jack stands.

Park Inside Your Garage or Buy a Car Cover

Harsh weather is hard on your vehicle all over. Try to park indoors whenever you have the opportunity.

If your car sits outside for unused for days or weeks on end, buy a car cover. Get one that’s large enough to cover your wheels too.

Keep Vehicle Away from Ozone-Producers

Appliances in your garage could be emitting ozone. If you find any, it’s best to remove them from the vicinity.

Conclusion

Knowing how to fix cracked tires is handy. Now that you know what signs and symptoms to watch for, you can catch early onset cracking early. Hopefully, you’ll be able to delay costly replacements.

The main takeaway here is that prevention will always be the better choice. It takes little effort to follow good maintenance practices. Parking indoors or using a car cover won’t take more than a couple of extra minutes a day.

Do you have questions for us about dry rot or any experience of it? Let us know in the comments section; we’re looking forward to hearing from you!

Kyle Palmer

From childhood go karting and motocross, to collecting and obsessing over scalextric, matchbox and radio controlled cars, I've always had an obsession with cars. Learning through manuals, books, trial and error, and more knowledgeable family members, I've also enjoyed tinkering with the mechanics and electronics of any vehicles I've owned. Now, over 3 decades later, I've started this site as a place for me to share my knowledge, to teach others how to care for and maintain their vehicles themselves, at home, so they can get the most of their vehicles and save a pretty penny compared to always seeking out professional help.

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