Tire Cracking on Sidewall

About Tire Cracking, The Ozone, & Old Tires.

Most of the tire cracking I see is normal wear and tear, most drivers will wear out their tires before tire cracking becomes a problem.

But if you have noticed small or large cracks in your tires, and are not sure if they’re safe, it’s best to get them checked out asap. 

What causes tire cracking?

Just like anything rubber and left exposed to the elements, it’s going to perish and crack. If the rubber is inflated, like a ball or tire, it’s going to go flat too, because air escapes through the rubber. 

Tires too are porous by nature, and with all the layers and glues, and belts used in a tire’s construction, it’s not good to have air seeping into the tire’s carcass. That’s why a rubber inner liner, or tube, has to be used to slow down the air loss.

Most tires today are “tubeless”, meaning the tube is built into the tire’s construction and not a separate component, but there’s still a small air loss that occurs through all rubber naturally which contributes to the tire cracking. That’s why we have to top off tire pressure periodically. 

Just as air seeps through the tire from the inside, the sun and ozone attack the outside causing a reaction in the rubber that causes them to crack. 

So tire manufacturers use a chemical additive to rubber called “antiozonant” to protect from harmful UV rays and ozone. The catch is that antiozonant only works if the tires are being driven, going through their normal heating and cooling cycles.

As a rule, the less you drive, the more your tires will crack. That’s why tire cracking is common on vehicles that don’t get driven that much, like trailers, motorhomes, classic, collectors, and performance cars, as well as grandma’s Taurus and the church van.

At Kenwood Tire Company we see a lot of tires — some age well while others crack, rot, and bloom for no reason.

Are your tires cracking? Check out some of these pictures people send me for an opinion and compare them to yours — 

Michelin Tire Cracking Chart

Is Tire Cracking a defect? 

Usually not. 

No matter how much you drive, dry rot and ozone-cracking can become a problem on most tires after 6 years. That’s why tire manufacturers end warranty coverage and recommend replacing your tires every 6 years, whether they’re worn out or not,

But if your tires are less than 3 years old and cracking, there may be a problem with the tire manufacturing process and it could be considered a tire defect. 

It takes a trained eye, but when a customer has a concern, I use Michelin’s nifty Ozone or Weather Cracking Visual Tool as a guide. 

Steps you can take to protect your tires.

You cant reverse tire cracking — just like us, dry rot and cracking are inevitable :-), but there are products you can use to delay cracking and/or enhance the appearance of your tires. 

At Kenwood Tire, we use a few products to clean and protect our customers’ tires and wheels – Right now we’re trying out the Chemical Brothers Diablo Gel tire and wheel cleaner with great results on all wheel types.

See how it works on the brake dust of this Mercedes GLK350 —

When it comes to tire shine, I’m not a big fan, but it’s ok to use a tire protectant like sunscreen, just make sure it’s not silicone or petroleum-based because these types of protectants actually speed up the tire cracking and dry rot.

My longtime favorite is Wizard”s Tire dressing and Protectant because it’s water-based, and doesn’t leave a residue and sling product all over your car!

My advice? Just drive! — Even if you have nowhere to go, getting your tires hot and through a driving cycle will make them last longer.

Thanks for visiting – I’m Spencer, the owner of Kenwood Tire & Auto Service in West Bridgewater, Massachusetts. If you’re concerned about your tires cracking, send me pictures as these people did, and I’ll give you an opinion. 

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Michelin Tire Cracking Chart

Dry-Rot & Tire Cracking Explained

If you have seen cracks on the sidewalls or between the treads of your tires, it may be dry-rot and that’s not good.

When is it time to replace cracked tires? Check out this handy chart from Michelin —

Just like us tires weather and age, their rubber becomes brittle, breaking down and creating cracks in the sidewall, tread, and around the rim.

Dry-rot is also known as weather cracking, and ozone cracking.

Tire manufacturer warranties will cover tire cracking and dry rot, as well as other defects, but most warranties expire after 6 years.

Most tires will wear out before cracking becomes a warrantable condition.

That’s because antiozonant, the rubber additive manufacturers use to resist tire cracking and tire-blooming too, is only released as the tire is being used, going through its normal heating and cooling cycles. That’s why RV, trailer, and classic car tires don’t get used that much, so cracking and dry-rot appear faster. 

There is no way to fix dry-rotted and cracked tires, but you can slow down the process by using a tire cleaner and protectant.

I use Superior Products Dark Fury to clean wheels at the shop, but for occasional use, I recommend Chemical Guys Diablo Wheel Gel – Used with a soft brush, both of these are awesome at dissolving brake dust without hurting the wheel finish.

And to keep your wheels looking good after cleaning, you can use a non-solvent protectant Wizards Tire and Vinyl Shine.

Check out examples of dry-rot in tires –  If you’re concerned about your tires, e-mail me some pictures and I’ll give you my honest opinion. 

Thanks for visiting, let me know if you have any questions or comments – 

Check out some more of my favorite wheel cleaning products on Amazon – (As an Amazon Associate, I earn from qualifying purchases).