Maintenance

Old Tires

If you leave your car sitting for awhile, you can create a flatspot on the tire :(

Tires absorb heat and long-term exposure to sunlight can cause serious damage. Tires should be stored away from equipment that produces ozone, which can cause ozone cracking or dry rot. link

Air Pressure

Check your tire (and spare tire) pressures once a month. Tires lose about 1-2lbs of air pressure a month or by 10 degree change in temp. So better to overinflate the tires a little :). Low air pressure fuel loss calculator

The recommended tire pressure is located inside the door edge (or fuel box or glove box). The pressure of tires increase when you drive to about 4 psi higher after 20 minutes. So you should let tires cool before checking pressure.

After 2007, vehicles have a Tire Pressure Monitoring System (TPMS). The official TPMS symbol is a yellow exclamation mark inside a tire cross-section. This symbol will light up when tire air pressure drops by 25% or more.

Nitrogen

To use nitrogen, you must perge tires form compressed air. You can top off nitrogen with compressed air, but unsure why you cant do reverse or even why u need to perge tbh... Maybe its unstable.

Hard to find free nitrogen from autoshops, so best to just use compressed air.

Benefits:

larger molecules so less leakage
less moisture build up, so more stable pressure

Efficiency Losses

Under inflation, will lead to more wear of thread of tires & lower driving effiency.

The Department of Energy has found that underinflated tires can decrease fuel efficiency by 0.4% for every 1 psi drop in the pressure of all four tires. Also, gas usage increases significantly as you exceed 60 miles per hour

There can be around a 10% change in energy due to rolling resistance for EVs vs 4% for gas.

Uneven Wear/Misalignment

Tires may get misaligned. They will generally produce wear on the edge of tire or cause some pulling of the car.

They could be due to a variety of factors, such as bearings worn or springs worn in suspension, and can be caused by hitting major potholes or hitting a curb.

Tire Balancing

You will notice your steering wheel/seat/or/floorboard vibate >45 mph. Heavier vehicles dampen vibrations so they have less imbalances overtime.

If your tires spins unevently/has vibration, you can use a balancing machine to measure rotation

This is called Dynamic imbalance
- then the shop will add tire weights to wheel to create even rotation
  - Types:
    - 1: Knock on wheel weights (clip onto rim of wheel) (most common)
    - 2: Adhesive wheel weights inside wheel
  - 1/4 ounce -> 4+ ounces

The tire may also become oval shapped

This is called Static Imbalance
- the shop will rotate the tire low point to the wheel's high point to get more roundedness

Rebalance recommended 6k miles, which is between 1/2 -> 1 year. But you can just kinda note if you have been driving in poor conditions or if feel some misalignment and go to shop to adjust. Free if bought @ discount tires.

Tire Rotation

Threads wear out in front of car (due to higher weight of engine) first. So, good to swap the back and front tires to extend the life of car. Free if bought @ discount tires.

https://www.discounttire.com/learn/tire-rotations

You should rotating your tires every 6-8,000 miles, or every other oil change. When moving the front tires to back, you swap the left and right tires front tires when moving to back.

Directional Tires

Some tires are directional, so you can only place them in a certain orientation. They can either optimize for performance in wet or dry conditions, but not both.

If swapping these tires, for forward and back, you can just move them, but if left to right, you would need to remove and reverse tire.