Why do tyres crack?
Why tyres develop cracks
Tyre cracking, also known as dry rot or weather cracking, is caused by the rubber compound drying out and losing flexibility over time.
Main causes
- Age — Rubber naturally degrades over time, even on tyres that are stored and never driven on
- UV exposure — Prolonged exposure to direct sunlight accelerates the breakdown of the rubber compound
- Ozone and heat — Environmental exposure hardens the rubber and makes it more brittle
- Underinflation — Running tyres below the correct pressure increases flexing and stress on the rubber, which can promote cracking
- Chemical exposure — Contact with solvents, fuels or harsh cleaning products can damage the rubber
When to replace
Small surface cracks on older tyres are common and may not immediately require replacement. However, deep or widespread cracking, particularly on the sidewall, weakens the tyre structure and means the tyre should be replaced without delay.
