Yesterday was a warm, sunny day in Atlanta (85°F), and I was out in the garage, touching up some paint on my daily driver. Suddenly, I heard what sounded like a 12 gauge, or a hand grenade go off just outside. I mean LOUD! Walking outside I saw what looked duck feathers floating down, and a 'blast zone' near the front of my project Mk2. The front tire had literally exploded. It was in the sun, and I had probably overfilled it over the winter, to ease rolling the car around. I never dreamed a tire could explode like this, just sitting unused. This tire had been the car's spare, and although it showed no visible dry rot, a close exam showed it a Brazilian "Monarch Sport 165R15"..........dated Feb. 1979!

 

The "duck feathers" were bits of the Tyvek car cover, which blew 16 feet out from the car.
The steel belts were shattered.

 

Ouch. I have full intention of replacing all my tires this spring even though they seem OK and have plenty of tread left. Not sure how old they are but over ten years with possibly 3000 or 4000 miles on them.

 

that shot-gun sound was often heard BITD when tires had tubes (pre 60's) . even a bicycle tire will make an awful racket when the tube explodes.

 

The same goes for rubber hoses. They carry hot oil or water and, apart from UV in sunlight, suffer as much as or more than tyres. Perhaps a tyre blow out can be more dangerous, but changing a water hose on the side of a busy motorway is as risky as changing a wheel - certainly a wheel is more straightforward. Some hoses are in horrible places, like the one from the back of a V12 to the heater (I still have the scars) or underneath the supercharger on the top of a V8. The consequences of a burst water hose, like head gasket failure, can be expensive and might not appear for several months. A few bad experiences have made me very wary of rubber components that are exposed to heat and internal pressure. For a car that has regular use, after 10 years hoses are well into borrowed time.

 

That tyre was grossly over inflated to break the steel belt or had a fatal flaw in manufacture or the sidewall would have let go first..

 

looks like the steel belt rusted away to me.

well, THAT... and a whole lot of pressure.

 

A similar thing happened to me in the mid 1990's with the spare tire of my MGB. Either the tube or tire exploded and the tool box that was sitting on top of it was thrown upwards with enough force that it bent the trunk lid. I had to source another trunk lid and since I was a college kid at the time I couldn't afford to paint it to match the rest of the car. I could afford 3 cans of Krylon spray paint and some masking tape. I ran this trunk lid for several years until I graduated and could afford a proper repair.


There are a lot of people who don't appreciate the amount of energy stored in a tire.

 

The steel belt is certainly corroded but still should not be first to fail. The belt is also of strange manufacture. Why Michelin is the largest tyre manufacturer in the world by tonnes of rubber milled. They make everything from dump truck & LHD tyres, to car tyres to bicycle tyres. People are prepared to pay for quality.

 

Just how "overfilled" was the tyre (tire)?
In addition, was the car rolled regularly or just sat in the one position all winter allowing a flat spot to develop?
Actually, failing as it did may have saved some downstream grief if the spare had to be used on the side of the road.
It has alerted me to check the spares in my current fleet. I suspect some of them are pretty old.