Buying Used Tires & Safety Inspection

used tires on trailer
These used tires are being sold to a tire shop to be used on the road again.

Used tires can be a great way to save money when maintaining a vehicle. Most salvage yards only charge $10-$20 per tire unless they’re part of a matching set. Tires are one of the most overlooked and yet durable and important components on a vehicle. Aside from the operator they are the front line of safe travel. Tires are crucial as the entire vehicle relies on them to keep it connected to the road. The National Highway Safety Administration estimates that every year roughly 11,000 tire-related crashes happen. Take a few minutes and read below to brush up on tires and tire safety.

Are Used Tires Safe?

The short answer, YES! A used tire is just as safe as a new tire so long as its in good condition. Just because something is used doesn’t mean that its lower quality. You can purchase perfectly good safe used tires for pennies on the dollar from most auto recyclers. BUT, you need to possess the ability to inspect a tire before you purchase it. Knowing about tires can help prevent you from spending extra money or worse having a catastrophic failure from an unsafe tire.

Lets start by going over some basic information about the different types of tires, tire sizes and ratings, and tire maintenance.Then we will dive into some of the things to look out for when purchasing used tires.

Tire Types, Ratings, & Sizes.

Tires come in all different types, ratings, and sizes. You want to make sure you are putting the correct tires on your vehicle. The first step when searching for tires is finding out what size tires your vehicle takes. You can find this in your owners manual, on the drivers die door jam, or through a google search. If your vehicle is an AWD you may want to avoid running uneven or miss matched tires as this can cause transmission damage.

Tires have the type, size, and rating, along with the DOT information written on the sidewall. In the image below you can see the tire size is [ P215/60R16 ]. The first letter “P” stands for Passenger. You only want to use P (Passenger Metric) or LT (Light Truck Metric) and never use a trailer (ST) or temporary (T) tire on your vehicle. “215” is the width of the tire in millimeters. Then you see a slash followed by the number “60”. This 60 is the aspect ratio of the tire. Aspect ratio is the sidewall height compared to tire width. Next we see an “R” followed by the number “16”. “R” stands for Radial, and the “16” is the rim size in inches. You cannot put a 15″ tire on a 16″ rim and vice versa. I’ve had quite a few customers ask me if they can put different diameter size tires on their rims. The answer is no.


Once you know your tire size and rating, you want to pay attention to speed rating and the load index. You want to make sure you are not over loading or over driving your tires as this will lead to a catastrophic failure. You can find the suggested ratings for your vehicle in your owners manual or look online.

How to determine the age of a used tire?

So now that you know what size, speed, and load ratings are, you want to look at the DOT information on the tire. You only want to use DOT rated tires, as these have been tested and are safe for the road. If there is no DOT information on the tires you are looking at do not use them. The DOT number tells you where the tire was made, and most importantly when. At the very end of the DOT sequence is a 4 digit code that tells you the week and year the tires were manufactured. Do not use tires that older than 10 years.

how to tell how old tires are

Inspecting The Condition of Used Tires

Now that we understand the basic information provided on the side of the tire, we need to inspect the overall condition of the tire. This is where taking your time and being thorough will ensure you get a good safe tire. Also, its important to note that most yards sell their used tires as-is where-is with no warranty or refunds so you don’t want to get stuck with a new tire swing or flower planter.

Tread Depth and Uneven Wear

The state inspection requirement is 2/32nds of tread depth. If you take a penny and stick Lincolns head into space between the tread, the tread should protrude over the tip of his head, if not the tire is below 2/32nds, near bald and dangerous. Good tread is essential to maintaining control of your vehicle. Good tread allows water and snow on the road to be pushed into the voids around the tread allowing your tire to maintain contact with the road while driving.


Uneven wear is something to avoid as this can cause alignment and steering issues. I will usually roll the tire along the ground inspecting the “horizon” of the tire. You should notice a nice straight roll with even wear across the horizon, with no bumps or abnormalities in the tread. Sometimes tires will have broken bands inside them or bubbles and rolling is a good way to detect this. Never use tires that have bulges or weird abnormalities in the shape.

even tread wear

Weather Cracking

Another thing to look for while rolling the tire is to make sure there is no “weather cracking” on the tire anywhere. Cracks are a sign the tire has started to degrade. Eventually these little cracks will begin to leak air. You can also be looking for screws, nails, or other foreign objects that may have punctured the tire. Punctures can be patched as long as they not too big, and are an inch away from the sidewall on the face of tread. If a tire has a hole along the edge of the tread or in the sidewall the tire is no good.

weather cracked tire

Check the Bead

Now that you have inspected the exterior of the tire and determined it to be good, check the bead and the interior of the tire. The bead should not have any tears or major cuts in it. Sometimes you can get away with minor shallow nicks that are a result of the tire machine. But again use caution as there needs to be adequate surface area for the bead to seal inside the rim.

good and damaged tire beads

You also want to look at the inside of the tire to make sure there’s no plugs, or punctures you missed from the outside. If you see wear marks on the interior of the tire or loose rubber grounds inside then the tire is no good. This happens when the tire is driven under-inflated and the weight of the vehicle causes the rim to eat into the base of the tire. Under no circumstances should you ever use a tire that shows interior wear.

interior wear and tire plug

Directional Tires & Matching Tires

You can’t mix and match Directional and Non-Directional tires. Most tires are non-directional meaning they can be mounted either way and it won’t make a difference. If you have directional tires on your vehicle you need find directional replacements. A directional tire means the tread pattern is designed to roll in one direction. You can usually figure this out by looking at the tire sidewall. Look for an arrow with the words “rotation” printed somewhere on the side. You can also figure this out by looking at the tire tread as it won’t be asymmetrical like a non directional tire.

directional tire example

For a Maine state inspection you are allowed to run tires that don’t all match as long as they are all non-directional and put on in matching pairs. This means that the tires on the front are identical to one another, and the tires on the rear are the same. Each axle should have a matching pair in order to pass an inspection. All wheel drive vehicles need to have 4 identical tires in order to avoid mechanical damage to the transmission.

Tire Pressure

The National Highway Safety Administration estimates that keeping up on your tire pressures can save you %11 in fuel costs ever year! Tires should be regularly inspected for proper pressures and overall condition. Regularly checking the pressure will extend the life of your tires and decrease the likely hood of a catastrophic failure due to under-inflation. If your tire looks low, check it. Another useful tip is to feel your tires after you have driven (make sure there not too hot first!) as a warm tire can be a good sign of under inflation or other mechanical problems that need attention.

flat tire

In conclusion I hope this helps while your on the look out for some good used tires.  Used tires can be a great way to cut down on the cost of vehicle maintenance and save money. Not to mention getting the full use out of a tire helps to reduce waste. Who knew “recycling” could be so great!

3gs tire

If you don’t have time to go to the junkyard to find a used tires and you are looking to save money, you could try a tire shop like 3G’s tire in Portland, ME. They offer used tires mounted, balanced, and installed starting at only $35.00 per tire. You can visit their website here: or give them a call 207-772-1255.