1. Lesson 8: Tires & Steering

2. Welcome to the Tires and Steering Lesson.
In this lesson we will cover:
Tires
Steering
How they work
How it works
Maintaining them
Checking power steering fluid
Inflation
Rotating & balancing
Checking tires
Alignment
Buying tires
Size
Mileage ratings
Changing a tire
Tire pressure monitoring systems

3. What’s the difference between a tire and a wheel?

4. Tires
The tires on your car are the only link between your car and the road. They are a lot more than just pieces of rubber—they have been carefully designed to maintain traction and contact with the road under all conditions. Making sure that your tires are up to this task is your responsibility!
The treads on your tires are designed to channel water and snow out from under the tire so that the tire can stay in contact with the road.
If the tire is not inflated correctly or is worn too much, it will not channel water away fast enough. This results in hydroplaning or loss of control.
Obviously, tires are very important to your safety. Yet, for most car owners, tires are the most neglected item on the vehicle. Don’t let your tires fall into this category!
Treads

5. Keeping your tires properly inflated:
According to the National Highway Traffic Safety Administration (NHTSA), low tire pressure-related crashes are to blame for 660 fatalities and 33,000 injuries every year. In addition to this, Americans would save roughly 5 million gallons of gasoline every day if everyone kept their tires inflated properly. If these statistics aren’t enough to convince you, consider that the average driver could increase the lifespan of his or her tires by 40% by doing nothing more than maintaining the correct tire pressure!
If your tires are properly inflated, the entire tread will contact the road, resulting in better traction, better fuel economy, uniform tire wear, and fewer accidents. Under-inflated tires will wear more on the outside edges, while over-inflated tires will wear more in the middle as shown:

6. Recommended tire pressure
As we learned in an earlier lesson, each automobile has an “ideal” tire inflation pressure. This information is found on the “tire placard” that is usually found inside the driver’s door or inside the glove box. Your owner’s manual should also have this information.
Can you find the recommended tire pressure on the placard shown below? Go to your car and look for your tire placard!
People often mistakenly assume that their tires should be inflated to the pressure shown on the sidewall of the tire. This is only the maximum pressure that this tire can withstand. Over- or under-inflating your tires can cause poor traction, rapid tire wear, low fuel economy, and even a severe accident.
Always follow the pressure specifications on the tire placard!

7. Do your tires look like this?
Worn on outside edges
Worn evenly across tire
Worn in the middle

8. Effects of low tire pressure on traction
These photos show a tire driving through water with different inflation pressures. This tire is supposed to be inflated to 35 psi. You will notice that when it is properly inflated, the entire tire contacts the road, but when it is underinflated very little road contact is made.
35 psi sitting still in water
35 psi at 60 mph
Good contact; the tire disperses the water well
30 psi at 60 mph
Poor contact; the tire does not disperse the water and the dark areas show that the tire is only contacting the road on the very edges
If the tires do not disperse water, a film of water remains between the tire and the road, causing a loss of traction and vehicle control.
25 psi at 60 mph

9. Tire pressure should be checked monthly
There are several reasons that tire pressure should be checked at least once a month. Here are just a few:
Even tires that don’t have leaks lose enough air each month to drop about 1-2 psi in pressure
For every 10° F change in temperature, tire inflation pressure will change by about 1 psi
For every 1 psi your tires are below the recommended level, your fuel economy suffers by approximately 0.4%
Under-inflated tires get very hot while driving, increasing the likelihood of a blowout (which often results in a rollover)
It is nearly impossible to tell if a tire has low pressure by just looking at it; use a gauge
If your tires are under-inflated or over-inflated, they will wear rapidly, costing you hundreds of dollars in unnecessary tire purchases.

10. Tips for checking tire pressure
Keep a tire pressure gauge in your car
The easiest way keep your tire pressure in check is to buy an inexpensive pressure gauge and keep it in your car. But don’t just keep it, use it often!
If you need to add air to your tires, many gas stations have an air compressor you can use
Tire pressure should be checked cold
This means that you should only check and set your tire pressure when the car has been sitting still for at least three hours or has been driven less than 2 miles.
Check your spare tire, too!
Many people forget to check the pressure of their spare tire until they need their spare and discover that it is flat!
Your spare tire often calls for a different pressure than your other tires. Check your tire decal to find this information.
Return to I-learn now and watch the video entitled, “Checking and Adjusting Tire Pressure.”

11. Rotating your tires
Each of the four tires on your vehicle wears differently. For example, because the front wheels are constantly being steered back and forth, they tend to wear faster than the back wheels do. Also, the front tires on a front-wheel-drive car and the back tires on a rear-wheel-drive car wear at different rates because they “slip” on the pavement more often.
To get the most out of your tires, you want all four tires to wear at the same rate. To make this happen, you should rotate your tires (or move them to a new position on the car) every 6,000 miles.
You really don’t need to make an extra trip to the shop to get your tires rotated. Having your tires rotated every 6,000 miles means that it can be done at every other oil change.
An added bonus—while the wheels are off, ask your service professional to check your brakes. Since it requires very little extra work, they may do this at no charge!

12. If you choose to rotate your own tires:
There are many different patterns to choose from when deciding which tire to move where. However, what matters the most is that the front tires get moved to the back and the back tires get moved to the front at each rotation. If no rotation period or pattern is to be found in your owner's manual, rotate your tires at least every 6,000 miles and follow one of the patterns suggested here.

13. What does “balancing tires” mean?
“Balancing tires” involves putting small weights on the wheel to “offset” any heavy spots that might otherwise cause a vibration when the wheel is spinning. An imbalanced tire and wheel assembly can result in a vibration that causes premature wear of tires, struts, shocks and other components.
Most wheel and tire balancing today is done on a computerized balancer.
How do I know if I need my tires balanced?
The typical symptom of a tire balance problem is a vibration in the steering wheel that is very pronounced only at a certain speed. The vibration may go away or lessen as you speed up or slow down. While this type of vibration can occur at any speed it is most likely to occur at highway speeds.
Many people don’t wait for symptoms but have their tires routinely balanced at every other tire rotation. This is really up to you!

14. Is that tire worn out?
In order to be considered safe and legal, all of your tires must have at least 1/16 inch of tread on the entire tread area of the tire. This means that even if most of the tire is fine, but one edge is worn too low, the tire should be replaced.
The penny trick: An easy way to check your tire tread depth is to use a penny. Stick the penny into the grooves in the tire tread, Lincoln’s head first. If all of his head sticks out above the tread blocks, on any part of the tire, it is time to buy new ones.
This tire is worn beyond the legal and safe limit of 1/16 inch. All of Lincoln’s head is visible.
This tire is in very good condition. It has plenty of tread depth and will maintain good contact with the road.

15. Wear indicator bars
Another way to determine the condition of your tire is to look for the wear indicator bars; almost all tires have them. When the treads are worn down to the point that they are even with any of the wear indicator bars, they are at the 1/16 inch limit.
The treads on this tire are worn to the point that they are even with the wear indicator bars. This tire should be replaced.

16. Wheel Alignment
What is wheel alignment? When a wheel alignment is performed, what happens is exactly as it sounds—the wheels are aligned so that they all point in the same direction. If any of the wheels on your car are misaligned by even a fraction of a degree, you may experience problems.
What causes wheels to get out of alignment? There are three things that can cause this:
Normal “wear and tear” on the suspension components
Bent or damaged parts caused by hitting a pothole or curb, or because of a minor accident
Repair work to your car that involved replacing a steering or suspension component
Usually, you cannot tell if your wheels are misaligned by just looking at them. However, there are ways that you can know. They will be discussed in the next few slides.

17. Wheel alignment angles
There are three different angles that have a major affect on your wheel alignment:
Camber
Caster
Toe
Camber is the inward or outward tilt of the wheel. Ideally, the wheel should be straight up and down. However, many things can cause it to lean in or out too much.
Caster is the forward or backward leaning of the steering axis. The motorcycle shown below has a lot of “caster.”
Toe is the direction that the wheels are pointed. Obviously, we want all of our wheels pointed in the same direction—straight down the road; in the real world, a lot of us may need to have our “toe” adjusted a little!

18. Camber
A “camber” problem will cause the affected tire to wear rapidly on the edge that it is leaning toward. It will also make the car “pull”—or want to drive to one side when you let go of the steering wheel. If you experience either of these symptoms, get an alignment!

19. Caster
Caster is the angle that has the least effect on your steering and tire wear. However, if the caster angle is bad enough, it can cause a slight pull to one side.

20. Zero Toe Toe-in Toe-out
If your front or back wheels are not pointed in the same direction as each other, the tires will not roll well down the road—they will actually have to “scuff” down the road sideways. This is the most common alignment problem and is the primary cause of premature tire wear. An incorrect “toe” condition won’t cause the car to pull to one side, but the scuffing will cause the tires to wear with a “feathered” edge. To detect a feathered edge, run your hand across the tread of the tire. If it feels smooth in one direction but rough in the other, you have a “toe” problem!
Slight feathered edge
Extreme feathered edge
Did you know?
If your toe angle is incorrect by as little as 1/10 of an inch, the scuffing that will happen to your tire is equivalent to dragging your tire sideways down the road about 50 miles per year.

21. When should you get a wheel alignment?
Generally, it is recommended that you have a wheel alignment performed when you purchase a new set of tires.
Realistically, you probably don’t need one if you don’t notice any of the symptoms of wheel alignment problems. If you notice any of the following problems, you should have a wheel alignment performed as soon as possible:
Uneven or excessive tire wear
The car pulls to one side (check tire pressure first; a low tire on one side will also cause a pull)
A crooked steering wheel (when going straight down the road, your steering wheel should be straight up and down)

22. Click here for the answers!
Do you see any problems?
Now, with all that you have learned about tire pressure and alignment, can you look at these tires and identify any problems?
Click here for the answers!

23. How did you do? Here are the answers:
Under-inflation
Worn on both outside edges
Camber problem
Worn more on one edge than the other
Over-inflation
Worn in the middle of the tire
Toe problem
Feathered edge caused by scuffing

24. Buying Tires
There is a great variety of tires that will fit on your car. How do you know which one is best for you? Hopefully the person who is selling you the tires can answer some of your basic questions—but more importantly—hopefully you will know what questions to ask!
Tires with aggressive tread patterns are good in mud and snow, but may be very noisy on the highway. You should try to find a tire that is a compromise and will give you the benefits that are most important to you.
Tires have mileage ratings. They are rated for the approximate number of miles the tire will last. If you buy the cheapest tire available, it may only last you a little more than a year. Most tires sold today are rated for between 20,000 miles and 80,000 miles.
Tip: You should do everything you can to make sure that your tires wear out evenly so that when it is time to replace them, you can replace all four tires at the same time. This is especially important in all-wheel-drive vehicles; all tires must be exactly the same diameter. The key to this is rotating your tires!
Different types of tires available
Do you need snow tires in the winter? Snow tires (and studded snow tires) are designed to have optimum traction in the ice and snow. However, if you have all-season tires on your car that are in good shape, you probably don’t need to buy snow tires. But before winter comes, make sure your tires are in good shape; if they are not, replace them!
Studded snow tires

25. Reading the tire
Have you read any good tires lately? Well, reading tires may not be much like reading a good novel, but there is a lot you can learn from a tire.
While there is a great deal of information on the sidewall of a tire, perhaps the most important numbers are the size and the date code.
SIZE: The tire shown above is 185 mm wide, is 75% as tall as it is wide, and fits on a 14 inch rim. You should never have two tires of different sizes on the same car! Can you find this information on your tires?
DATE CODE: The tire shown above was manufactured in the 27th week of A tire that is more than 6 years old may be unsafe. When were your tires made?
Optional Link: Click here to learn more about tires

26. The time to prepare for this event is now!
Changing a flat tire
Because flat tires are relatively rare today, many of us aren’t prepared for the event that we might have one. Even though flat tires are rare, odds are likely that you will experience many flats during your lifetime!
The time to prepare for this event is now!
Tip: If you get a flat tire, pull over immediately (if it is safe to do so). If you drive on a flat tire for even a short distance, the tire will be permanently damaged and will have to be replaced.
Make sure that you know how to jack your car and change a tire
Check and make sure that you have a jack and a lug wrench in your car
Take your lug wrench out and make sure it fits all of the lug nuts on your wheels!
Make sure that you have a spare tire and that it is properly inflated
Read in your owner’s manual about specifics to your vehicle and your spare tire—remember that spare tires are only for temporary use!
Return to I-learn now and watch the video entitled, “Changing a Flat Tire.”

27. Do you have a slow leak?
If you have a tire that seems to always need some air or seems to always get low faster than your other tires, you probably have a small leak in the tire.
Chances are good that you have a nail or screw in your tire somewhere. If the problem isn’t fixed, it may get worse and lead to a flat tire.
Nail
A leaking or flat tire can usually be fixed very inexpensively. Just take the tire (or the entire car if the tire is still on the vehicle) to a repair shop.
If the leak or hole is in the tread area of the tire, they can patch it for you. If the leak is somewhere on the sidewall of the tire, it cannot be repaired.

28. Tire Pressure Monitoring Systems
All 2008 and newer cars are required by law to have a tire pressure monitoring system. Some cars have already used systems like this for years. Basically, each wheel has a sensor in it that measures the pressure of the tire. The sensor then transmits a radio signal to the computer in the car that displays a message if any of the tires is not inflated properly.
Remember that just because you have a tire pressure monitoring system does not mean that you don’t need to check your tires anymore! Your car does not have a brain—you must use yours!

29. How a steering gear works
The Steering System
We probably have a pretty good idea of what our steering system does. It allows us to drive, turn, and control our cars with ease. Steering systems require very little maintenance. However, the one item that should be checked occasionally is the power steering fluid. When you are under your hood checking your other fluids, take a moment to check on this one:
To check your power steering fluid, find the reservoir, remove the cap, and check the level. Some cars have a dipstick attached to the reservoir cap, and others use an opaque reservoir with “min” and “max” marks.
If you have to add fluid, look in your owner’s manual to find out what type of fluid to add. Although you can buy generic “power steering fluid,” it is not the best choice for all cars.
How a steering gear works

30. Conclusion
All of us want to keep our cars on the road and keep them going straight! We also want to get our money’s worth out of our tires and steering system.
In this lesson we learned how to make sure that our tires and steering system are working properly and will keep us safe while driving.
We have covered tires, how they work, and how to take care of them. We also have learned how a car owner can identify problems with the tires by performing simple occasional inspections.
This lesson covered the routine maintenance and service that car owners should have performed—such as tire rotation and balance, wheel alignment, and checking power steering fluid.