The first pneumatic tire was invented during the year 1888 in Belfast, Ireland by John Boyd Dunlop. His invention is still used by more than 1.5 billion vehicles throughout the world. With most vehicles having 4 tires (some have upwards of 10!) that comes out to over 6 **BILLION** tires by low estimates. That is a lot of material that needs to be produced and inspected/maintained! Are your tires and wheels safe for the harsh conditions they must endure? Let's explore the basics of tire/wheel inspection for your vehicle throughout this course.

Basic Tire History

Introduction

Vehicles come with multiple sizes of tires. You can easily identify your size that's currently on the vehicle by looking for this format. **NOTE** *Your vehicles correct original tire size will be shown on the driver's side door jam.* The letter P represents a "Passenger" rated tire while some tires have an LT stamp that stands for Light Truck. Both applications have different uses and weight ratings associated with them, most vehicles will have standard passenger tires. In this picture 265 represents the width of the portion of tire touching the ground in milimeters. 75 represents the side of the tire as a percentage of the overall width of the tire in milimeters (i.e. 75% x 265 = 199 mm). The final R15 represents a Rim diameter of 15 inches. This is the opening of the tire where the wheel sets/seals and bolts to the vehicle. 

Size of Tire

Another important part of a tire is the date that the tire was produced and manufactured. Circled in yellow is the official DOT stamp that shows information about where the tire was produced and the exact location inside the facility. The final numbers are the important ones, these represent the date the tire was produced. Some tires may have these numbers on both sides of the tire or just one side so you may need to look at the portion on the inner part of the vehicle. Tires with white letters will only have these numbers on the white letter side. As shown in the photo 3010 represents the 30th week of 2010. This tire is almost 14 years old! That's pretty old for a tire! Tire manufacturers start to recommend replacement at the 6 year mark while 10 years is the maximum age for a tire to be put in service on the road. These time limits vary depending on what application and climate the tire is in. Tires become hard and brittle as they age when the internal components of the tire start to break down. 

Manufacture Date of Tire

We could go on for a very long time about different characteristics for tires. Tires need different types of rubber compounds, sizes and overall construction depending on their use and climate. Knowing how to identify your tire size and age will help you for future situations. Now that we know some of the basics of a tire let's get to inspecting that rubber!

Basic Tire Knowledge Wrap-Up

Basic Tire Knowledge

Tools to inspect your tires? Yep! They will come in handy and will ensure your safety! Make sure you are in a safe environment to inspect your tires and wheels with appropriate clothing. If assesing the inner part of your tires, please make sure the vehicle is safely in park with no risk of the vehicle moving. Preventing the vehicle from moving with a wheel chock is preferred if inspecting the inner part of the tire.

1. Tire Pressure Gauge
2. Tread Depth Gauge
3. A pair of gloves and good lighting

Tools Needed For Inspecting

This tool is called a Tire Pressure Gauge and will tell us how much pressure is being held within the tire. You can purchase this at any automotive store or on-line retailer. Tire pressure is **EXTREMELY** important in how the tire functions and carries out the vehicles task. Different vehicles and tires require certain pressures in order to function properly. Tire pressure also greatly affects your fuel mileage and effiency. Always refer to the small tag located on the driver's door jam to set your tire pressures. This tag is displayed when you open the drivers door on the body of the vehicle or possibly the door itself. Circled in green is the part that will attach to the "valve stem" of the tire/wheel assembly to show the pressure (circled in yellow) of the tire wheel assembly! Also, circled in green, the back side where you attach to the valve stem can be used to release pressure from your tire if overinflated, cool! These pressures are read in PSI (pounds per square inch) or kPa (kilopascal) and will depend on your region.

Tire Pressure Gauge

This cool little tool is called a Tread Depth Gauge. It gives us both a color based visual and actual measurement of the tread depth that is touching the ground giving us our traction! Tires are measured by 32nd's of an inch. Most new tires come with 10-14 / 32nd's of usable tread. During Normal operating conditions (dry/small amount of rain/snow), tires will start to experience decreased traction/braking control in the 4-7 / 32nd's range while Extreme (wet/icy, heavy snow/rain) will have greatly diminished traction/control. When we get to the 3/32nd range, Normal operation of the vehicle has greatly diminished and Extreme operation has been almost eliminated that will cause a severe threat to the operator. Complete loss of traction and control can occur at the 3/32nd range. Depending on region, tires that measure at or below 2/32nd's of tread are legally required to be replaced. Let's make sure those shoes on our vehicles have plenty of tread for all of our safety!

Tread Depth Gauge

Finally, let's have a pair of gloves and good lighting on hand. Tires or objects around the vehicle can injure hands or other body parts if not properly prepared. Shine the light around the tire/wheel assembly for a better visual inspection. Now that we have our tools, let's head out to the tires/wheels in a safe location with the vehicle in park!

Gloves and Good Lighting

Locate the tag typically found on the driver's side of the vehicle inside the door jam. This is located on the body of the car or sometimes on the driver's door itself. Some vehicles may also have information in the owner's manual of the vehicle. This will also display the original size of the tire as well as how much weight the vehicle can carry with the original sized tires. **NOTE** The tag shown in this photo does not match the tire we will be inspecting. =)

Tire and Load Information Tag

Now that we have gathered our information on the tire for the vehicle, let's take a physical look at the tire! **NOTE** Repeat inspection for all the tires on the vehicle as some tires may have different wear patterns/damage vs others on the vehicle. Don't forget that spare tire!

1. Red Ring - This area of the tire is known as the bead. This is where the tire seals against the wheel to hold the presure in for the tire. Inspect this area for any tears, cracks, pieces of rubber sticking out. These may indicate an issue with the bead of the tire and may require replacement of the tire.

2. Yellow Ring - This area of the tire is known as the sidewall. This is where general information/brand/model of the tire is displayed. This portion of the tire is the "cushion" when the tire experiences variances in the type of terrain being traveled acting as an absorber that compresses. Inspect this area for tears, cracks, slices/gouges, bulges and dry-rot. This area of the tire is the most exposed to sunlight and is prone to cracking/drying out. Large potholes that compress the tire too much will tear the fibers inside the sidewall and create a large bulge that requires immediate replacement. Smaller sidewalls are more prone to these bulges.

3. Green Ring - This area of the tire is known as the shoulder. It connects the sidewall to the tread with plys of steel/mesh fabric to give the tire it's "foot" that meets the road. The shoulder is also exposed to the dangers of sunlight but also meets the road, especially when turning/cornering. Inspect this area for any sort of slices/gouges, chunking, cracking, foreign objects and uneven wear. 


Hey, that tire looks pretty great! Let's go ahead and check over the tread of the tire!

Visual Inspection of Bead/Sidewall/Shoulder

Welcome to the tread of the tire! This is where the tire meets the road and gives us the traction we need. Think of this as the bottom of your shoe - if we don't have a lot of tread, we're gonna be slipping and sliding! The green portions are still sections of the shoulder where they meet up with the area between known as the tread. The tread provides all of our traction, stability and noise producing sounds. This is also where our tread depth gauge comes into play! Let's grab the gauge and measure in three different locations across the tread represented in red. We're measuring three different zones due to tires having adverse wear from failing suspension components/alignment and improper inflation. Tires with these issues may have more or less tread towards the inside/outside of the tire. If a noticable difference is found between the three zones inspected, have the vehicles alignment/suspension inspected. After we've gathered our measurements we're going to inspect the tread around the tire for foreign objects, cracks, gouges/chunking and peeling tread. 

Visual Inspection of Tread / Tread Depth

Great! The tire looks safe from the outside. **NOTE** Although a tire may look safe with no known issues on the outside, there is no guarantee of the condition of the inside of the tire until it is dismounted. Tires over 10 years of age or tires in very hot/dry conditions may have concerns on the inner portion of the tire not visible to the eye. Lets go ahead and check our tire pressure and complete our visual inspection of the wheel!

Wrap Up of Visual Inspection

Inspection of Tires

Hope you didn't misplace that tire pressure gauge! Let's go ahead and grab that when we're done inspecting the tire.  First, inspect the valve stem (circled in red) to ensure that it is not rusted, petrified or cut/sliced. Unscrew the valve cap (circled in green) and carefully attach the gauge to the valve stem of the wheel. The backside of the gauge will eject and display the pressure inside the tire. The pressure is located just past the bottom of the gauge housing in PSI/kPa. Verify the amount is within 1-2 psi of the placard on the vehicle. **NOTE** Be careful when checking pressures on vehicles equipped with TPMS (Tire Pressure Monitoring System). These valve stems sometimes have a metal valve stem that is prone to breaking/snapping if not treated carefully when attaching tire pressure gauge / air chuck. The tire will rapidly lose air if snapped off and a new sensor must be purchased. Let's move on to inspecting the wheel!

Checking Air Pressure

This is the wheel. This seals the tires air and bolts onto the vehicle to make us go down the road! It can be measured by bolt pattern, diameter/width and offset. 

1. Red Circle - This is where the wheel is bolted to the hub of the vehicle. Typically most wheels will have 4 - 8 lugnuts holding the wheel on. A tire iron or the appropriate sized socket/tools will remove the lugs. Inspect this area for loose lug nuts that attach to vehicle, cracks, severe rust/corrosion and egg shaped holes near the lug nuts. The egg shape holes are from the wheel becoming loose and gouging the lug holes out. 

2. Yellow Circle - This is the face of wheel and has different styles or finishes. Inspect this area for cracking/spiderwebbing, abrasions and rust/corrosion. 

3. Green Circle - This is the lip of the wheel and seals the tire against the wheel. Inspect this area for cracks, bends, abrasions and rust/corrosion. If the wheel is severely bent, it may cause a vibration. This area of the tire is prone to rusting/corroding and may cause tire to leak. If slow leak is present, check the bead/lip area with soapy water. It will bubble if a leak is present. Major scuffs, dings or bends in the lip may also cause damage to the bead of the tire when tire is removed/installed on the wheels. Rust or corrosion on the inside of the wheel may require replacement of the wheel.

Inspection of Wheels

The biggest maintenance concerns when it comes to tires is to have correct tire pressures, rotating the tires periodically and having good maintenance on suspension components accompained by alignments. Inspect/set tire pressures to values located on the vehicle's placard every 1-2 weeks. Have the positions of the tires on the vehicle rotated by a professional or DIY if training/tools are available every 5,000-6,000 mi / 8,000-10,000 km. Inspect suspension components by trained professional every time tires are rotated or if uneven wear on tires is detected.

Maintenance

We've inspected our tires and wheels and we're safe to head down the road or to complete a task for a job. I hope you've all enjoyed this course and appreciate all feedback. Have a great day and safe travels.

Conclusion

Inspecting your vehicles tires/wheels is a quick and easy task to ensure the safety of not only yourself but other occupants of the vehicle as well as motorists driving around you. In this course we will cover the basics of tire safety as well as go over basic characteristics of a vehicle's tire/wheel. 

Inspect your vehicles Tires/Wheels with this course.

Inspecting Your Vehicles Tires / Wheels

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