Tire Inspection for Summer Road Trips
The sun is out. Temperatures are heating up. The kids are out of school. So it’s time to pack up the car, get out and have some fun.
Summertime is prime road-trip season. But before you hit the open road, there are a few simple tire tips that will give you some peace of mind and keep you safe while driving longer distances during the hot summer months.
Measure Your Tire’s Tread Depth
Summer heat is your tire’s enemy. When it’s hot outside, tire rubber breaks down and wears out more quickly as it rolls over gritty, scorching road surfaces. Over time, your tires will become less effective at gripping the road.
Measuring tread depth regularly and before you head out on any road trip longer than two hours is a simple and effective way to help ensure that your tires can still grip and stick to the road, keeping you safe. There are a couple of easy ways to do this, using either a tread depth gauge or a penny.
A tire tread depth gauge is the most accurate way. Tread depth gauges can be found online or at your local auto parts store, and they are easy to use. All you have to do is stick the probe into the shallowest groove on the tire, press the shoulders of the probe flat against the tread and then read the result. Take three different measurements across the tread of the tire and consider the smallest measurement your tread depth. All gauges should measure both in the U.S. 1/32" standard and in millimeters.
If you don’t have a tread depth gauge handy, a penny can also be used to check the wear on tires in the critical last 1/32" increments of their remaining tread depth. Here’s how it works: Place a penny with Lincoln’s head upside down and facing you into the shallowest groove on the tire. If all of Lincoln's head is visible above the tread, you only have 2/32" or less of tread depth left and your tire has reached the end of its useful life. Similar to using a tread depth gauge, check the depth in three different places across the tread and if you see all of Lincoln’s head in any of the measurements, replace your tires before heading out on a road trip.
When you measure your tread depth, also look at the tread for signs of uneven wear, cracks, foreign objects or other signs of damage. If you see something that doesn’t look right, have your tires inspected by a professional before you set out for the long drive. It’s better to find out you need new tires before you hit the road.
Check Your Tire Pressure
There are many benefits to proper tire inflation, including prolonged tire life and improved fuel economy. But the summer brings some extreme road conditions and rising temperatures that require regular tire checks, especially before an extended road trip.
The summertime heat causes the air inside your tires to expand, increasing your tire pressure. Overinflation can result in decreased handling, reduced impact absorption and premature wear, which increase chances of a blowout, especially in well-worn tires.
If a tire is underinflated, the oven-hot roads and the friction between the road and the tire cause the tire’s rubber and construction to break down more quickly, decreasing performance and increasing the chances of tire failure. So it’s important that your tires be accurately inflated to provide the best handling, traction, durability and safety.
You can check your tire pressure using a tire pressure gauge or an air compressor. And, if possible, try to check your tire pressure when the tires haven’t been driven on for at least thee hours. The recommended air pressure for your tires — which can be found in the owner’s manual or on the driver’s side door jamb — is based on their cold inflation pressure. Heat causes the air in tires to expand, so if they haven’t been sitting in the sun and haven’t been driven in three hours or for more than a mile at a high rate of speed, then they can be considered cold. Check your tire pressure before they have hit the road or been in the sun and then inflate them to the recommended pressure at that time.
If you check your air pressure when tires are warm — from driving, when there are warm ambient temperatures or if they have been in direct sunlight — and it matches the vehicle manufacturer’s recommended inflation pressure, then they could be anywhere from 2 to 5 psi underinflated when cold, but there’s no accurate way to tell.
No matter how much tread you have or how accurately your tires are inflated to recommended levels, road hazards are still out there, so don’t forget to check the tread and air pressure while you are on your road trip. And don’t forget to inspect your spare tire as well.
Check Your Tire Load Capacity
Load capacity is the maximum amount of passenger and cargo weight that a vehicle is designed to handle, and it varies greatly from vehicle to vehicle. Going on a road trip often means loading more in your vehicle than you would normally carry — luggage, clothes, people, pets, etc. Even if you own an SUV or a minivan, it doesn’t mean that you’re free to overpack or stack suitcases on the roof. Knowing the load-carrying capacity of your tires helps prevent you from unknowingly putting undue stress on them by loading more than they can carry.
Load capacity can be calculated by subtracting the vehicle's curb weight — the weight of the vehicle without any cargo and only half a tank of gas — from the gross vehicle weight rating (GVWR), which is the maximum permissible weight the vehicle can carry. If you have an SUV with a load capacity of 1,000 lbs. and you put five 190-lb. adults inside, you can carry only 50 lbs. of luggage. Also, keep in mind that gas weighs about 6 lbs. per gallon and, if your SUV has a 15-gallon tank, filling up would leave you with just about 5 lbs. of carrying capacity.
It sounds confusing, but, luckily, this payload calculation has been done for us on most vehicles already and can be found on the driver’s side door jamb or in the vehicle owner’s manual. It would read something like “The combined weight of occupants and cargo should never exceed” a certain weight. So make sure you factor in all those extra swimsuits and beach towels when packing for vacation! Your tires will be the better for it.
Heavier loads, longer distances and hotter temperatures have played a role in derailing many summer vacation road trips. Prepare properly: Don’t overpack, don’t drive too fast and do keep an eye on your tire pressure and tread depth to make sure that your tires do their part in getting you where you want to go and back safely.