Flat tire, thumping, pulling to one side? Whatever you do, don't grab the jack first. Get somewhere safe, loosen the lug nuts with the car on the ground, then jack it up. Wrench before jack. Every time. The car's own weight holds the wheel still for you. But the step that matters most happens before you even stop. It's not the one you think. Step 1: get away from traffic. Parking lot, side street, exit ramp, or a level, well-lit right shoulder.

Step 2: park, engine off, brake on, hazards on, cones about 100 feet back, passengers away from the road. And wedge the tire on the opposite corner from the flat, so the car can't roll off the jack. Step 3: car still on the ground, loosen each lug nut a quarter to half turn counterclockwise. Step 4: jack under the metal frame where your manual shows, flat about 6 inches off the ground. Step 5: nuts off, flat off, spare on with the valve stem facing you, nuts hand-tight in a star.

Step 6: lower it till the tire touches, then tighten fully with the wrench, same star pattern. Step 7: check the spare's pressure, then drive straight to a repair shop. 50 mph, tops, on a donut. Myth: jack it up first, then spin the lug nuts off. In the air, the wheel just spins with the wrench. On the ground, the car's weight holds it. Myth two: stop the second it goes flat, or you'll ruin the wheel.

If an exit or lot is close, it may be worth driving there on the flat, rim and all. Here's why: a rim costs less than getting hit. The farther from traffic, the safer you are. Jack spot next. Plastic body parts can crack under a jack. The metal frame takes the weight. And never put any part of your body under the car while it's on the jack. The star pattern? Going across the wheel instead of around it pulls the wheel on evenly.

And the donut is built light, for short trips only. 50 mph is the ceiling, not a target. But what if you open the trunk and there's no spare at all? Happens more than you'd think: 28 percent of 2017 model year vehicles had none as standard. A sealant kit can temporarily seal a small tread puncture. Sidewall or blowout? Roadside help or a tow. Nut won't budge, bad weather, or an unsafe spot? Call roadside assistance instead of taking the risk.

Stuck in a travel lane? Hazards on, call for help, and stay buckled, facing forward. Wrench before jack, frame not plastic, star not circle, and 50 on the donut. Check your spare's pressure at least once a year. It loses air in the trunk with no visible sign. Because a rim is cheaper than you. And a flat spare is just extra weight.