Tire Sidewall Cracking: Cause & When They Are Unsafe?

Robert Herrera-COR-Wheels

By Robert Herrera

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Even the highest-quality rubber is subjected to wear and tear, troubling seasoned drivers with dangerously cracked tires! Indeed, many readers have sent us letters on tire cracking, asking our team for tips to identify its symptoms, root causes, and appropriate solutions.

Our inclusive guide will deliver all there is to know about this. Scroll down for more information. 

Why Do Tires Crack? Reasons Behind Small Cracks In Tire Tread

A. On The Sidewalls

1. You Use Seasonal Tires For All Years

One popular reason behind tire cracks is that drivers use their seasonal tires all year round (instead of just one season), which is a big no.

Why do we strongly disapprove of such usage? Simple: their designs are not meant for any other extended periods of time. 

Let’s take summer tires, for example, whose harder compounds only thrive in ambient temperatures. For conditions below 44 degrees F, they will seize up, leading to violent cracks on the tire’s sidewalls (and sometimes even treads). 

The same goes for winter tires used on hot days, whose structures are inadequate to handle increased temperatures. 

2. Humidity, Heat, and UV Light

Oscillating temps cause tire contraction and expansion, ultimately resulting in premature cracks. This sentiment is particularly true for people storing tires in substandard environments with broad temp changes. 

Worse, tires that already have tiny cracks will allow water to penetrate, accelerating the tire’s breakdown even more. 

On another note, UV lights are another critical factor your tires must avoid at all costs – unless there is no other choice. We suggest parking the car in a garage (or, if you have no garage, within a shade). 

3. Air Pressure

Underinflated tires will generate significantly more heat than usual, expanding and contracting the tires to the point of absolute cracks. 


How about overinflated tires? They are no less deadly: too much pressure stretches the tire’s inner compounds, raising the risks of cracking, bulging, and even blowouts. 

Thankfully, the issue is easy to fix and prevent: all you need to do is to air the tire properly. Note that some tires require different PSI rates for different seasons (compared to the recommended value, lower/increase the air pressure by 1-2 PSI for every 10°F drop/rise in temp). 

4. Low-Quality Shines

High-quality shin products are designed to keep tire crackings at bay – or at least slow down their process. Unfortunately, many vehicle owners opt for shining products that are either subpar or too aggressive, drying out the tires in seconds! 

Worse, some of such products are aquaphobic, making you feel like your tires were a barren desert. No doubt the cracks pop up!

5. Age

Nothing lasts forever – and car tires are not an exception. Even with optimal care and maintenance, they can only last you to a certain extent. 

Hence, for too-old tires with developing cracks on the sidewall, the best solution is to have them immediately replaced by experts. 

Ignoring the issue is out of the question: cracked tires alone already result in blowouts and accidents, let alone a cracked and old tire! 

B. On The Treads:

While sidewall crackings are more popular (and also unavoidable), tread cracks are rarer and much more urgent, demanding immediate diagnoses. They indicate serious dry rotting that may blow off the tire entirely, putting the car at severe risk of control loss and accidents.

So how do cracks in the tread of tire occur? Normally, a typical tread crack will appear on the sidewalls first. Without proper treatment on your part, they gradually move to your tire’s outer compartment and slide beneath the tread

What Are The Symptoms of Cracked Tires?

Symptoms of Cracked Tires

As its name suggests, tire cracks are characterized by signals of rubber compounds cracking or wearing down. You will also notice some of the following signs: 

  • Brittleness. Dry rots dry out the tires, leaching out their essential oils. As a result, they will feel much more brittle. In some cases, there will even be tiny rubber pieces breaking off the surface. 
  • Visible tears. Whether the rots are harmless or severe, visible tears will litter all along the sidewall. They either appear isolated or expand to the hubcap’s large portions
  • Tread cracks. As previously explained, advanced sidewall cracks also affect the tread’s outer edge. Even when your treads still have perfect overall depth, these cracks still severely impact your handling. You will find it a struggle to control the car on the road. 
  • Faded colors. Check its color clearly: does your tire start to look grayer instead of black? Dry rots and cracks are clearly the culprits. After all, fading and cracking often go hand in hand.

Are Brand-New Tires Prone to Rubber Cracks, Too?

Yes, since old age is not the only root cause behind cracking. 

Still, you can breathe a sigh of relief: since the tires are freshly bought, most of these cracks are just harmless, minor scuffs that scratch lightly on the sidewalls. A bit of quick servicing at the tire manufacturer will do. 

Are Tire Cracks Dangerous? When Are Cracks in Tire Sidewall Unsafe?

Yes, though the answer also depends on the crack type. We suggest observing its intensity closely. 

Are the tread surfaces lined with small, miniature cracks? You and your car are safe, fortunately. However, larger ones spanning across your tire’s entire length signify disasters, calling for immediate tire replacement

Note that the crack size correlates with its wear-down speed: in short, the bigger they are, the faster they will degrade. So tend to the problem as soon as possible (when the rots still look small) to avoid unnecessary hassles and potential danger.

Can Cracks Be Repaired? 


Some people may ask us, “Why not? I have seen many cars with fixed cracks!” But no, these are not permanent fixes; only temporary ones for appearance. 

More specifically, aftermarkets often sell cheap fillers to seal these cracks and protect the car’s cosmetics. However, such aesthetic treatments by no means reverse the crack’s impacts. 

Thus, remember to assess whether these cracks are serious based on our insights in the previous sections (refer back to: When Are Cracks in Tire Sidewall Unsafe?). If their degradation is startlingly quick, you must have the tires replaced by technicians right away. 

How to Prevent Tire Cracks In The Future?

Better be safe than sorry; here are ways to ensure the issue can no longer bother you: 

  • Shelter The Tires: keep them from direct sunlight, petrochemicals, and ice. 
  • Drive Often: Tires barely used or stored for too long will deteriorate in cold, dry winters. Bring them out often to maintain the tires’ lifespans. 
  • Be Careful During Your Cleaning Tasks: Only use water and mild soap as your tire cleaners. Stay away from petroleum-based and ethanol cleansers – since they break down the tire rubber more easily. 
  • Check Tire Pressure. Keep an eye on the tire’s air pressure. Raise or reduce them accordingly to ensure their PSI is always in check
  • Check The Tire’s Expiration Date. Locate the DOT letters on the sidewall. Then inspect the last 2 numbers that represent your tires’ production year. (ex: 20 is 2020). 


How Long Should A Tire Last Before It Cracks?

Good news: around five to seven years, given great maintenance! 

Are Tire Cracks Warranty-Covered?

Yes, for the first four to six years in most cases. The warranty expires after that. 


Our detailed discussion of possible causes, symptoms, and fixes for tire cracks has hopefully lent you a great overview of the issue. Check the tires’ conditions frequently to keep dry rots at bay, and have old tires swapped for new ones to guarantee maximum performance.

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Robert Herrera

President & Automotive Expert at COR Wheels

Robert Herrera has been with COR Wheels for 17 years and has a great passion for the automotive industry. During his time at COR Wheels, he has driven and test-driven a variety of vehicles.

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