Tires and wheels in Project Zomboid

Every wheel on a car has two numbers in the mechanics window (press E near the car, or right-click and choose Vehicle Mechanics): condition and pressure. Condition drops with distance driven, with off-road driving and with crashes. Pressure is the air in the tire, and you set it with a Tire Pump.

A tire at 0% condition is finished. It cannot be patched back into service, so the only fix is to take it off and fit another. A car with a missing or ruined wheel will barely move and pulls hard to one side, which is the usual way players notice a flat in the first place.

Build 42 changed how air behaves. Player reports from early Build 42 say tires now lose pressure while you drive, where in Build 41 the value stayed put, so the pump matters more than it used to. Players also report that a wheel can come off when pressure or condition gets very low. They disagree on the exact cutoffs: one reply put the risk below 25 pressure, another corrected it to below about 5 pressure or 15% condition. Treat both as rough guides and keep your tires topped up.

Changing a wheel needs three things, all carried in your main inventory rather than inside a bag:

• Jack: lifts the car. Required for taking a tire off and putting one on, and also used for some brake and suspension jobs.
• Lug Wrench (a Tire Iron also counts): removes and fits the wheel nuts. It is a tool, not a weapon.
• Tire Pump: adds or lets out air after the wheel is on.

You need Mechanics level 1 to remove or install a tire, and no recipe magazine. The same rule applies on every vehicle class, which makes tires the first job most new mechanics learn. See the Mechanics skill guide for how the skill levels up and the tools guide for the rest of the kit.

1. Park on flat ground, turn the engine off and clear any zombies nearby. The job takes several seconds and makes you an easy target.
2. Open the mechanics window and right-click the bad wheel. Choose Uninstall. The tire goes into your inventory; at 15 weight it is heavy, so drop it if you will not reuse it.
3. Right-click the empty wheel slot and choose Install, then pick the replacement tire from the list.
4. Right-click the new wheel and choose Inflate Tire. Keep going until the pressure reaches the tire's maximum. The same menu has a deflate option if you overshoot.

Sources differ on whether removing a wheel empties it. Early Build 42 players reported removed tires coming back at 0 pressure and falling off within a few meters. A Build 42.20 guide says uninstalling no longer drains the tire. Either way, check the pressure on every wheel you fit before you drive off.

A failed install or removal gives 1 Mechanics XP and can damage the part, so at low skill carry an extra part in case one breaks.

Tires come in three quality tiers, and each tier comes in three sizes that match the three vehicle classes. The item name shows both, for example "Tire - Regular (Heavy-Duty Vehicle)".

• Classes: Standard (family cars such as the Chevalier Nyala or Masterson Horizon), Heavy-Duty (vans and trucks such as the Step Van, Franklin Valuline and Dash Bulldriver) and Sports (the Chevalier Cossette, Dash Elite and race car). A tire only fits a car of its own class.
• Quality: Old, Regular and Performance. Better tires grip harder, wear more slowly on the road and take more air.

All tires weigh 15. The figures below come from the game's item data as listed on pzfans.com (one source). Friction and wear vary a little by size, so ranges are given.

Lower wear numbers mean the tire lasts longer. Note how much faster every tier wears off the road than on it. To check which class a car belongs to, use the vehicle list.

Pressure changes how the car drives. A developer note from when inflation was added said that more air lowers wheel friction and braking force, and warned against over-inflating. So a tire pumped past its normal value slides more in corners and stops later, while a soft tire risks falling off.

Opinion: fill each tire to its listed maximum and no further, check all four every time you stop for fuel, and avoid fields and forest tracks unless you must, since off-road wear is five to ten times higher. Mixing tiers on one car works, but matching tires on each axle keeps grip even from side to side. For more on handling and speed, see driving.

• Other cars. The easiest supply. Any parked car of the same class carries four tires you can take with the jack and lug wrench. Pick the wheel with the best condition in the mechanics window.
• Trunks. Car trunks sometimes hold a loose "Tire - Regular" as a spare.
• Auto shops and mechanic garages. Tires spawn on mechanic wheel shelves, along with pumps and wrenches. Check the loot locations guide for shops near you.
• Junkyards and parking lots. These are where many vehicles spawn, so they are good for stripping wheels.

About half of regular tires found as loot spawn already damaged (one source), so inspect before you carry one home. Opinion: keep one spare of your car's class, a jack, a lug wrench and a pump in the trunk at all times. Once you have a base, store extras in the garage. Our vehicles guide covers the rest of the car, maintenance covers keeping tools in shape, and towing helps if a car is stuck with no spare.