Inspect and Read a Tire
Daily Dirt Education How-to & Tech Maintenance Skills

Inspect and Read a Tire

Skill Wed Tire TreadThose big round black things that your vehicle drives on is actually filled with not only air, but also a lot of technology.  Tires have a big responsibility for our general safety when driving, so keeping track of their well-being is important.  You want to visually inspect the tire, check tire pressures and understand the date of service on your tires.

Visually Inspect

There are a few different elements you are looking for when visually inspecting a tire including tread depth, bulging, cracking and separating.

Tread depth can be a simple measurement using a penny!  Take the penny and hold Abe's body between your thumb and forefinger.  Select a point on your tire where tread appears the lowest and place Lincoln's head into one of the grooves.  If any part of Abe Lincoln's head is covered by the tread, you're driving with the legal and safe amount of tread. If your tread gets below that (approximately 2/32 of an inch), your car's ability to grip the road in adverse conditions is greatly reduced.  Realize that this measurement is for car tires, for the thicker tread blocks on a offroad specific tire you need to adjust the tread depth.  

Bulging or cut of the sidewall is another potential problem that you can visually see.  A bulge is an internal break or damage of the cords within the tires sidewall.  A cut is where the sidewall is visibly sliced from the outside.  Generally these are caused by severe impact, or excessive age of a tire.

Tread SeparationWhile looking at the tread and sidewall, be aware of any cracking or dry damage.  If you store your vehicle or trailer for a length of time, be sure to rotate the tires and look at the whole edge.  One part of the tire may look fine, but an impact section may tell a completely different story.

Tire separation is also usually visible before it becomes an issue.  This is where the tire tread separates from the caracas or body of the tire.  You can see the rubber peeling away. When you see the strips of tire on the road, usually followed closely by a trailer on the shoulder of the road, they had a tire separate.  Hopefully they caught it before the whole tire blew out.

While on a road trip, it is common for me to do a walk around and quickly visually inspect all my tires, especially the trailer tires, while fueling at each stop.  Helps me stretch my legs and puts another ounce of confidence in my stride.

Rotate and Consider Inflation Pressure

BFGoodrich Tires
Diagnose Your Tire Problem by clicking on the correct image and it will tell you why that is happening to your tire:

Are your treadblocks wearing differently?  Your tires tell a mechanic a lot about your vehicle.  There are generally two simple solutions including rotating your tires more often and/or considering your tire pressure.  More complex solutions could include problems with your front end or needing a steering adjustment.  

When dealing with All-Terrain and thicker tire blocks, it is important to maintain a rotation schedule that keeps the treadblocks wearing evenly.  Beware that some tires are directional and can only be used going one way, normally these tires are used on passenger cars, not offroad capable vehicles.  There is a distinctive arrow on the sidewall of the tires that designate the rotation.

On an overinflated tire, the center of the tread bears most of the load and wears out faster than the outside edges.  You can overinflate a tire by checking the pressure when the tires are warm and filling it up to the suggested PSI.  Remembering that heat makes a tires PSI raise, it is suggested that you always check your tire pressures cold, or three hours after driving.  If this is not obtainable, then be sure to make an appropriate adjustment.  An underinflated tire reduces tread life through increased treadwear on the outside edges of the tire and can also create excessive heat in the tire which can lead to an earlier failure.

Air GaugeTire Pressure is a topic that should be taken up one-on-one with someone that understands your circumstance.  For instance, on my one-ton truck with 37" BFGoodrich Tires All-Terrain KO2 tires I generally run 5lbs psi lighter in the rear tires while driving around town and then put them to max psi before towing a trailer.  The weight and ride quality are altered considerably.

When coming off the trail where you aired down to make the offroad obstacles, it's important for your tire pressure to be set back to the vehicle's recommended PSI. On-road conditions require different performance from the tires, including high-speed stability, handling, and durability. These are all compromised by incorrect inflation pressure. Besides the safety issues, low tire pressure greatly impacts fuel consumption and increases tire wear.

Get a good air gauge.  Did you know that air gauges actually need to be calibrated?  The cheap air gauges that you get at the gas stations can't be calibrated and probably aren't very accurate.  Investing in a $15-$25 air gauge can make a big difference in being accurate.  Be sure to actually read the instructions on how to use the gauge correctly, there are some tricks to the more fancy gauges that gives you this accuracy.

Do You Have Old Tires?

Especially when considering that your offroad vehicle or trailer may sit for long periods of time and not have the tread wear or any other signs of age or damage, it is important to understand how to read the sidewall of your tire to know how old it is.  The week of manufacture is molded into the sidewall of each DOT-approved tire.

Look for a four-digit number at the end of the string of characters, following the letters DOT on the sidewall. The first two numbers indicate the week and final two numbers denote the year of tire manufacture. Tires that have been in use for five years or more should continue to be inspected at least annually.  It is impossible to predict when tires should be replaced based on their calendar age alone. However, the older a tire, the greater the chance it will need to be replaced due to the service-related evolution. While most tires will need replacement before they reach 10 years old, it is recommended any tires in service 10 years or more from the date of manufacture, including spare tires, be replaced with new tires as a precaution, even if the tires appear serviceable and have not reached the legal wear limit.  See the Full Example HERE on website

Whats Next

Head outside with a penny!  What do your tires look like?  How are they shaped?  What do the sidewalls look like?  Do you need to jack up your vehicle and do a rotation?  What are the dates on them?  Do you need to start working on a replacement plan?  Take control of your tires!  The last thing you want is a blowout on the trail or street because of simple routine maintenance. 

Author:  Charlene Bower

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