All Tire Ratings – How to Decipher Your Tires

Tire StackDo you know that all tire ratings are important? Have ever been in the market to buy tires? If so, then you have probably been asked several questions that you didn’t know the answers to.

Questions like what is the size tire you want or is there a specific rating that you are looking for.

These questions should not scare you away. The information is very important to the tire buyer because it will determine how often you buy tires, and for what season you should buy for.

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What do the numbers mean?

There is one big question that all tire sellers ask. What size tires are you looking for or need? The tire size for each vehicle is different but is always located in the same locations.

Usually in the vehicles owners manual or on the information sticker on the drivers side door or “B” (or middle) pillar.

All tire ratings usually have a three digit number with a forward slash followed by a two digit number and a letter or two ending with a two digit number(i.e. 235/40R18).

The first of the numbers is the width of the tire (i.e. 235). This means that the tire is 235 millimeters(mm) wide. The next digits are what’s called an aspect ratio.

This is a percent of the width of the overall tire meaning the side wall is a certain percent tall of the tires width.(i.e. 40). So in retrospect, this tires’ sidewall is 40% the width(235mm) of the tread pattern.

The “R” on the tires sidewall is the construction of the tire(i.e. R=radial).

The last of the digits of the tire is the rim size that the tire should fit(i.e. 18). This means that the rim of the vehicle is 18″ tall.

Tire Size Chart

Load and speed ratings – what do they mean?

There is often another set of numbers and a letter on all tire ratings. This information is called the load and speed rating. That means with each tire you can only carry up to a certain weight limit on each corner of the vehicle and can only go up to a certain speed with each rating.

The load rating (usually a two or three digit number) indicates the amount of weight that can be carried by each corner of the vehicle.

That number will usually start with 65(for smaller vehicles) and ends at 104(larger trucks). A higher number means that the vehicle can carry more weight per corner.

There is always a letter that is followed by this and that is the speed rating. These letters are (and in order): B, C, D, E, F, G, J, K, L, M, N, P, Q, R, S, T, U, H, V, W, Y, and ZR. Ratings are higher for different vehicles based on the tires recommended by the vehicle manufacturers specifications.

  • B – 31mph(50kph)
  • C – 37mph(60kph)
  • D – 40mph(65kph)
  • E – 43mph(70kph)
  • F – 50mph(80kph)
  • G – 56mph(90kph)
  • J – 62 mph(100kph)
  • K – 68mph(110kph)
  • L – 75mph(120kph)
  • M – 81mph(130kph)
  • N – 87mph(140kph)
  • P – 93mph(150kph)
  • Q – 99mph(160kph)
  • R – 106mph(170kph)
  • S – 112mph(180kph)
  • T – 118mph(190kph)
  • U – 124mph(200kph)
  • H – 130mph(210kph)
  • V – 150mph(240kph)
  • W – 169mph(270kph)
  • Y – 188mph(300kph)
  • ZR – over 150 mph( over 240kph)

These are the tire manufactures ratings for speed. Always refer to the owners manual and your vehicles manufacture recommended specs for the correct tires for your vehicle.

How to decipher the information on tires.

All tires also have specific ratings for tread wear, traction on wet roads, and temperature. The tread wear rating is a three digit number starting at two hundred and sometimes going up as high as eight or nine hundred.

This means that if the number is higher usually depending on the tires that the tread will not wear out as fast as a lower number. The way tire companies determine this information is with a test(or control) tire with a tread wear of one hundred. A tire that is rated for two hundred will last twice as long as the control.

Tire Treadwear Information

Furthermore, the higher the number of tread wear, typically the longer the tires will last.

Traction on a tire is determined by letters. AA, A, B, or C (ranked highest to lowest). This factor is determined by how soon a vehicle can stop on wet roads. A higher rating means that your vehicle will stop in a shorter amount of time on a wet road.

The temperature rating is always one letter. A, B, or C (ranked highest to lowest). Temperature is gained through friction on the road while you drive your vehicle. A higher ranking for temperature means that the tire is less susceptible to heat and blowouts while driving.

D.O.T. Code and what it means for your tires.

There is a ten to twelve alphanumeric code on each tire that comes off the factory floor and all tire installers use this code for their tire warranties. The first six to eight digits or letters are the tires make and model of each tire(i.e. 1A2B 3C4D).Tire D.O.T. Information

The last four digits are always going to be numbers(i.e. 0120). This is called the date code which tells tire installers when the specific tire was manufactured. It is read as the week the tire was made and in what year(i.e. 0120 the first week of the year 2020).

A tire will only last about four to five years after install before needing to be replaced. An older tire has a higher risk of separation( bubbling on the tread or sidewall) and blowouts. When a tire has become separated it must be replaced right away.

Choose the best tires for the season.

Some tires have specific seasons(i.e. summer or winter) when they should be installed. If you live in a snowy region your tires should be all season tires or winter tires.

These tires have specific ratings and needs that should be met when driving in colder climates. for instance winter tires can be studded or have a more aggressive tread to help grab traction on the snow or ice.

All season tires do not have to be studded and have a less aggressive tread pattern than winter tires but a more aggressive tread than summer tires.

Summer tires are better suited for warmer climates and summer. They will not have an aggressive tread unlike the all season tires and winter or snow tires.

All tires are rated for a certain season and will have a positive or negative impact based on when they are installed. Most tires will be a good tire all year round hence why they are called all season tires.

Know your tires and your vehicle better.

Now that you know how to decipher the information on your tires you can now answer questions that are difficult to answer. There is a lot of information on tires and it can be overwhelming at first.

Therefore, it will be easier to get the right tires for your vehicle.

All tire information can be found on the Sidewall of the tire. Always refer to your vehicles manufacture recommended specs for tires with can be found on the driver side “B” or middle pillar when looking for tires for the vehicle.

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