Seasonal Tire Tips for Heat, Rain and Road Trips

Heat raises tire pressure, softens rubber and speeds up aging. Hot freeway pavement on I-10 and SR-210 adds more heat on top of what the tire makes by flexing. An underinflated tire in that setting runs hotter still, which is when tread separations and blowouts become more likely.

Summer habits that help:

• Check pressure cold, before the first drive or 3 hours after parking, and set it to the door placard.
• Never bleed air from a hot tire to hit the number.
• Watch loads: a full car plus a cargo box on a hot day puts extra stress on tires.
• Park in shade when you can. Sun exposure dries out sidewalls.
• Look for cracking along the sidewall and between tread blocks.

Summer is also hard on batteries and AC. Our seasonal vehicle care guide covers the rest of the car.

Fine cracks in the sidewall or tread grooves come from sun, heat and age. Tire makers call it weather or ozone cracking, and people often call it dry rot. Shallow surface crazing is common on older tires. Deep cracks that open when you squeeze the tread, or cracks near the bead, mean the tire should be replaced.

Who sees this most:

• Cars that sit outside and are not driven much
• Trailers, RVs and boat trailers parked for months
• Spare tires, especially on truck underbody carriers
• Tires that look deep but are several years old

The last four digits of the DOT code give the build date, so 3223 reads as the 32nd week of 2023. Many vehicle makers advise replacement about 6 years from that week, and most tire makers treat 10 years as the outside limit no matter how deep the tread still looks. Our date code guide shows where to find it. We photograph cracking during inspections so you can see how deep it goes.

After months of dry weather, oil and rubber build up on the road. The first rain lifts that film and makes the surface slick. Tires with shallow tread cannot clear water as well, so stopping distances grow and hydroplaning comes on at lower speeds. That combination catches drivers who have not checked tread since spring.

Before the wet months:

1. Measure tread depth. NHTSA advises replacing a tire at 2/32 inch, where the wear bars sit, and drivers who want grip in a storm shop nearer 4/32 inch. California sets its own floor in Vehicle Code 27465 at just 1/32 inch across any two adjacent grooves, so a tire can be street legal and still be the wrong tire for a wet freeway.
2. Check that wear is even. Worn shoulders clear less water.
3. Replace wipers if they streak. See wiper blade service.
4. Set pressures, since cooler weather lowers them.

We measure tread at every tire visit and write the 32nds down, so you can see how much the last few months took. The federal tire safety guidance behind these figures is published at NHTSA (opens in a new tab).

Long drives and mountain grades put steady heat and load on tires. Before you leave, check pressure with the car loaded as it will be, look for damage and uneven wear, and check the spare. If you head up to the mountains in winter, know that chain controls can apply and plan for what your vehicle needs.

Pre-trip checklist:

• Pressure set cold, using the loaded-vehicle number if your manual lists one
• Tread depth and wear pattern checked
• No nails, bulges or cracks
• Spare inflated to the figure on its own sidewall, often about 60 psi on a donut, and driven within the speed limit printed beside it, commonly 50 mph
• Lug nuts torqued in a star pattern to the foot-pound figure your vehicle calls for, and re-torqued 50 to 100 miles after any wheel came off
• If towing, check the trailer tires too. We also offer a hitch and tow package inspection.

Planning a move instead? The U-Haul counter is on the same lot. See U-Haul rentals.

Match your tire checks to what the local weather is about to do. Summer is about heat and pressure. Fall is about getting tread ready for rain and busy school traffic. Winter is about wet roads and cold mornings. Spring is a good time to rotate and catch problems before summer.

The seasonal ready bundle groups several of these checks into one visit.

Late summer and the holidays are when families pack the most miles into a short time: school runs, sports travel and long drives to see relatives. A tire check before those stretches catches problems while there is still time to fix them. It fits in one short visit and pairs well with other seasonal work.

Carpool and family vehicles often carry more weight than usual, so use the loaded pressure from your owner manual if it lists one. Check the rest of the car with our seasonal ready bundle, or read our tips for safety-focused parents.