What Causes Tire Cracking?
4 Answers
Tire cracking is primarily caused by the following reasons: Traumatic cracking: This type of cracking occurs in irregular positions, shapes, and sizes, usually resulting from collisions, compressions, or scrapes with foreign objects while driving. Some cracks only appear on the rubber surface, while others may damage the tire body cords, with severe cases leading to instant deflation. Aging cracks: These cracks typically appear in the later stages of tire usage, often found on the tire shoulder or lower sidewall, and sometimes at the bottom of the tread grooves. This is a natural change in the tire rubber due to long-term flexing and heat generation. Prolonged driving with low tire pressure can accelerate this process, but it generally does not affect the tire's lifespan or safety performance, and early replacement is usually unnecessary. Notes: Early wear in the center of the tire. This is often caused by excessive tire pressure, which alters the shape of the tire tread, making the central part higher and leading to premature wear.
I chatted with the mechanic about this during my last tire change, and tire cracking is really quite common. The most frequent causes are aging and external damage: after four or five years of use, the rubber naturally hardens and cracks, especially for cars parked outdoors year-round under the sun. Tire pressure issues are also problematic—underinflation causes repeated flexing of the sidewalls leading to cracks, while overinflation leads to wear and cracking in the center of the tread. Poor road conditions, scraping against curbs, or punctures from nails can all cause structural damage. Some people like using tire shine products, but certain chemicals can actually corrode the rubber. Don’t overlook the impact of cold temperatures either—rubber becomes brittle in northern winters, making it more prone to cracking. If you spot cracks, check their location and depth. If sidewall cracks exceed 2 millimeters, it’s absolutely time to replace the tire—a blowout is no joke.
My decade-old car had this exact issue. Mainly due to aging, the rubber oxidizes and develops fine cracks resembling spider webs. Once I found a deep gash on the sidewall - turns out it got scraped against the curb while parking. Chronic underinflation is worse; the tire gets folded and creased repeatedly like crumpled paper, breaking internal cords. Repaired tires also tend to split open at the wound. Some opt for cheap used or retreaded tires, but their rubber strength is inadequate. Remember to regularly remove small stones lodged in tread grooves as they abrade groove walls when rolling. During inspections, focus on shoulder and sidewall areas - radial cracking patterns warrant immediate attention.
From a mechanic's perspective, tire cracking boils down to several key factors. First is natural aging - rubber becomes brittle after five years, and exposure to high temperatures accelerates this process. Second is mechanical damage, such as hitting deep potholes that break the tire's carcass ply, causing surface bulges and cracks. Abnormal tire pressure also plays a role: driving with low pressure causes excessive tire flexing, leading to repeated stretching and cracking at the shoulder area. Chemical corrosion is another common cause, with substances like engine oil or diesel degrading rubber molecular chains. Manufacturing defects are rare among major brands nowadays. It's recommended to check for cracks during monthly tire pressure inspections, rather than waiting until increased road noise signals a problem.
