ali pumped his car tyres to the fullest on a hot afternoon. That evening when it was much cooler,he measured the tyre pressure again. The pressure was very low. Why?
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Explanation:
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Heat can have a huge effect on your tires. The air pressure in tires increases as the temperature goes up. Scientists have figured out that for every 10 degrees (Fahrenheit) that the temperature rises the tire pressure will increase by one pound per square inch (PSI).
It doesn’t sound like much, but there’s typically only 30-35 PSI in the tires of passenger vehicles. A few pounds of air pressure can make a big difference. Such a big difference it can cause a tire to pop. Even if it doesn’t give out, over-inflation can cause a tire to prematurely wear and interfere with braking.
There are three things at play when the heat causes air pressure to build:
Hot Molecules
All materials are made up of atoms and molecules. When molecules get hot they start to vibrate intensely. The vibration causes expansion. Being that there are molecules in the air, it’s easy to understand why air-filled tires expand in the summer heat.
Friction
As you drive down the road your tires are rubbing against the asphalt. This generates a fair amount of friction, and friction creates heat that makes your tires even hotter during the summer.
Rubber
The third part of the trifecta is what tires are made of - rubber. Rubber molecules are linked together in long, twisting chains (polymers). When polymers vibrate they contract rather than expanding. Tire rubber is made so that the polymers can’t coil in on themselves, but everything has a breaking point. Think about a rubber balloon. If you keep blowing air into it eventually it’s going to burst. The same thing can happen to a tire when it’s hot out.
What to Watch Out For to Avoid a Blowout
Are you on the brink of a blowout? It’s a real cause for concern at any time of year, but in the summer it's more likely. Here are signs that you need to pull over and let your tires cool down.
Tires That Are Hot to the Touch
The most obvious sign that your tires are overheating is how they feel. If they feel hot to the touch it’s an indicator of overheating.
Excessive Air Pressure
A tire pressure gauge will tell you if your tires are overinflated from the heat.
But Don’t Rely on the Tire Pressure Monitoring System (TPMS)
Many newer vehicles have a TPMS that sends an alert when the tire pressure is too low, but your system won’t warn you if the pressure is too high. You’ve got to go old-school with a manual gauge.
What to Do to Prevent a Heat-Related Tire Blowout
Whether you live in Texas, California, Florida, Georgia or any other state, safe driving starts with taking a state-approved drivers ed course, understanding the rules of the road and maintaining your vehicle. There’s nothing you can do about the heat, but there are steps you can take to avoid a tire blowout during your next summer drive.
Keep Your Tires Properly Inflated
Safe road driving requires that tires have a certain amount of air pressure. What’s considered the proper amount of air pressure varies depending on the car you drive. Go with the vehicle manufacturer recommendation, which should be noted on the inside of the driver door and owner’s manual. Be careful not to confuse the “recommended” amount with the “maximum” amount listed on the tire itself.
Keep an Eye on the Air Pressure in the Tires
Measure the air pressure with a gauge before you begin driving. Check it again every two hours or 100 miles if you think overinflation is an issue.
Don’t Drive Until Your Tires Cool Down
You might think the best thing to do is let a little air out the tires so you can keep traveling down the road. Wrong! If you let air out you run the risk of driving on tires that are under-inflated, which is equally dangerous. The best thing to do is wait it out until the tires cool off.
Replace Worn Tires
If your tires are already worn thin they’re more prone to a blowout. Consider getting “summer tires” that are designed to handle better in high temperatures.
Clean and Treat Wheels
Treating your tires with a wax-based product can keep them from drying out, which decreases the possibility of a blowout.
Stay Within the Speed Limit
The slower you go the less friction there will be. Less friction means less heat.
Pay Attention to the Load Weight
The more loaded down your vehicle is the more weight there will be on the tires, increasing the likelihood of a blowout.
Next up - learn how to fix a flat tire if you do experience a blowout!