Pull off the road and assess the spot

To change a flat tire, park on firm, level ground away from traffic, secure the vehicle and follow the wheel-change instructions in your owner’s manual. If you notice thumping, vibration or a sudden pull while driving, hold the wheel steady, ease off the accelerator and steer and brake gradually as you reach a safe place. A parking lot gives you room to work. A narrow shoulder, slope or soft ground can make lifting the vehicle unsafe. Call roadside assistance if you cannot find a safe place or have an unusable spare. Once parked, switch on your hazard lights, set the parking brake, shut off the engine and select Park or the gear specified in the manual. Have occupants wait in a protected area away from traffic before lifting the vehicle. Set the wheel chock as directed. A common arrangement is to chock the wheel diagonally opposite the flat. AAA roadside guidance

Find the spare and loosen the fasteners on the ground

Locate the compatible spare wheel, jack, lug wrench and wheel-lock key if your car uses one. Some vehicles carry a sealant kit instead of a spare. Follow the kit instructions and call for help if the damage is outside its repair limits. For a wheel swap, confirm the spare is usable and locate the manual’s jack point nearest the flat. Remove the cover if it blocks the fasteners, then break each fastener loose while the wheel is still on the ground. Leave the fasteners in place until the wheel is raised. One Ford manual calls for a half turn counterclockwise at this stage. Use the procedure for your own model. Set the jack squarely at the specified point on firm ground and lift just enough to clear the wheel. Stop if the jack shifts or tilts. Keep hands, feet and the rest of your body clear of the underside of the lifted vehicle. Ford owner’s manual example

Seat the spare and tighten it to the specified torque

Remove the loosened fasteners and set them where they will stay clean. Pull the wheel straight off and place it flat so it cannot roll. Clear loose debris from the mating surfaces, line up the spare and seat it against the hub. Thread each fastener by hand. If one binds immediately, stop and check its alignment and compatibility before using the wrench. Snug the fasteners in the sequence shown in your manual, then lower the vehicle as directed and complete the tightening with a torque wrench set to the vehicle’s specification. Many vehicles use a crossing sequence to bring the wheel down evenly against the hub. The correct sequence and torque come from your manual. If a fastener is damaged, the wheel will not sit flush or you cannot secure it to the specified torque, get roadside help before driving. Store the removed wheel and tools securely so they cannot move around in the cabin. Honda manual example, “Replacing the Flat Tire,” in NHTSA’s archive

Check pressure and the spare’s driving limits

Use a gauge to check the spare against the pressure specified for that spare in the owner’s manual or vehicle information label. A compact spare often calls for a different pressure than the regular road tires. Read its speed and distance limits before moving and follow any restrictions on where it can be fitted. Head to a tire shop promptly so the damaged tire can be assessed and the regular wheel restored. A tire technician can also verify the wheel fasteners and check for damage from driving while underinflated. Before the next trip, check that your spare and tools are back in their storage locations. NHTSA recommends checking all tires, including the spare, monthly when cold. Its guidance defines cold as having been parked for at least 3 hours. Correct pressure and sufficient tread help the tire maintain traction in use. NHTSA TireWise · How friction creates grip