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what do the numbers on a motorcycle tire mean

If you read 120/70 – 12 51 S,it means:120 indicates the width of the tire (in millimeters)70 indicates the aspect ratio (between height and width)12 is the rim size (in inches)51 refers to the speed rating.S refers to the type of construction.

Table of Contents

How to tell if motorcycle tires are good?

When To Replace Motorcycle Tiresa) Tread Depth. To ensure that you don’t guess the expected lifespan of your motorcycle tires,manufacturers often add wear bar running across the tire tread.b) Age. As a general rule,the lifespan of your motorcycle tires should not go over and beyond five years. …c) Cracking. …d) Punctures and Cuts. …e) Loss of Pressure. …f) Odd Feeling. …g) Inflation. …

What do the first three numbers on a tire mean?

P – the tire is for P-metric passenger vehicles (regular cars,SUVs,light duty pickups of – ton load capacities).No letter – a metric-sized tire (in the US,mostly for SUVs and vans).LT – the tire is for light trucks (some SUVs,medium and heavy duty pickups of -1 ton load capacities).More items…

Do motorcycle tires last longer than car tires?

Moto tires do not last very long compared to car tires, and the faster or more aggressively one rides, the tire life is shortened proportionally. Moto tires are sold according to the expected use. Touring tires are expected to last the longest, but are the least forgiving when it comes to traction, because the harder rubber tread doesn’t stick to the road as well.

How to read Numbers on tires?

What Do Tire Numbers Mean?Type. Letters that stand at the beginning of the series are to inform the tire type. …Width. The next three-digit series – in this case is 215 – is to show how wide the tire is in millimeters. …Aspect Ratio. …Tire Construction. …Tire Wheel Diameter. …Load Index. …Speed Rating. …

What do Your Tires Say?

Now that you know how to read a motorcycle tire take a look at your bike and make yourself comfortable with the exact size and dimensions of your ride. It can be beneficial to know tire-speak next time you need to balance them or get a new set.

What is the first number on a motorcycle tire?

First Number. The first number inscribed on a motorcycle tire is there to indicate the width of your tire in millimeters. This width is measured by way of a straight line through the tire. It goes from one edge of a motorcycle tires tread to the other side.

What does 130/90 mean on a motorcycle tire?

In other words, the larger this second number is, the taller your motorcycle tire will be. For example, a tire that is written 130/90 means that it has a width of 130 mm and it is 90 percent as tall as the given width. When you calculate 90 percent of 130, that means it is 117 mm tall.

What is the difference between a smoother tire and a thicker tire?

Generally speaking, smoother tire tread will grip better on even, slick, and dry services. While thicker or chunkier treads are better for off-road conditions. There are various patterns designed for streets that perform best in wet and slippery weather. Many off-road tires also are available in a vast array of different surfaces, ranging from packed down soil to loose sand.

What is the carcass of a motorcycle tire?

Your tire carcass is essentially the body that is underneath the tread. In the case of motorcycle tires, they can be bias-ply or radial. This refers to the way the carcass of your tire is designed. In radial tires, reinforcing belts run from a bead on one side to the bead on the opposite side across your tread.

How much does a retreaded tire cost?

Generally, the prices will range roughly from $70 to $160. Some shops charge for installation of the tire, some don’t, and many will charge a small balancing fee. Retreaded tires can cost around 30 to 50 percent less than brand new tires.

What does the third number on a tire mean?

The third number on your tires indicates, more simply, the rim size or the circumference of your wheel. So, if the number is 18, that means your tire rim is 18 inches. A tire with a 16 as the third number has a rim size of 16, and so on.

What does 3.25H-19 mean?

Another thing to note is that these tires are not belted and are of bias-ply construction. An example is 3.25H-19. 3.25 symbolizes the width, H symbolizes the speed rating, and. 19 symbolizes the rim diameter in inches. The aspect ratio, though not indicated, is 100% meaning the height of the tire is 100% the width of the tire.

What is the metric system on a motorcycle?

Metric System. This system measures the size in millimeters. It is the most commonly used system for motorcycle tires, which is a set of three numbers and letters implying the width of the tire, the aspect ratio of the tire (ratio of tire ‘s height to the width) and lastly the rim size given in inches. Immediately after the speed rating, you will …

What is 50 aspect ratio?

50 = aspect ratio which is the percentage of the height of the tire to the tire’s width,

What does M mean on a motorcycle tire?

M is used to denote that the tire is a motorcycle tire

What does 90 mean in physics?

90 denote the aspect ratio. In this case it is 90%

What is the letter that precedes the speed rating?

A· The speed rating is usually preceded by letter “S”

How to find tire speed rating?

To find the maximum load and inflation pressure, you’ll need to check the sidewall of the tire. A speed rating also has a letter code, and that is immediately after the width and aspect ratio. It’s part of the three-digit load/speed index. This is on the tire, immediately after the complete size designation. A Z-rated tire has no maximum speed — this rating is for more than 149mph. Check out this table to see what letters correspond with what speed ratings:

How to measure width of bike tire?

Width is measured in a straight line from the furthest point on one sidewall, across the tread, to the furthest point on the opposite sidewall. If there is any question whether or not a larger than OEM tire will fit your bike, youre encouraged to call Tech Service.

What is bias ply tire?

“Belted” means fiberglass, Kevlar or aramid fiber belts, which has added strength and load capacity. But, if a tire does not have (R), then it is bias-ply, which means that it has multiple, overlapping rubber plies.

What are the factors that determine the size of a motorcycle tire?

There are five main aspects to determining the ideal motorcycle tire sizing: width, aspect ratio , speed rating , tire construction and rim diameter. Let’s take a look at each:

What is an inch tire?

These tires do not have an aspect ratio designation marking. The cross-section tire height is 100% of the width. An inch-sized tire is bias-ply construction and is not belted. However, these are being phased out and are not used on newer motorcycles.

What is metric tire?

Metric. Metric tires are most commonly used and can work for sport bikes, cruisers, touring bikes and others. If there is no speed rating, the “M” will precede the metric size. After the speed rating, there will be a “B” or “R” to indicate if it is belted or radial tire construction.

What is the alpha size on a motorcycle?

The Alpha size designation is most often used for touring motorcycle tires. Even if a tire doesn’t have a“B” designation after the speed rating, it could be belted.

Tire size

Each motorcycle model requires specific tire sizes that are indicated by the manufacturer in its technical data sheet. It is very important to try to stick to the recommendations for safety and to adhere to the regulations of the road.


You may have noticed that we are still missing a piece of information from the previous sizes (120/70 ZR 17). These letters indicate the type of internal construction of the tire, whether it is radial or diagonal. If it is radial, it is indicated with a letter R or ZR, while if it is diagonal, it is usually not indicated, i.e.

Load capacity and speed symbol

In this section we are going to look at the load capacity index and the speed category symbol, i.e. numbers and a letter after the tire size.

Other data

If we take a closer look at our tires we will see that there is even more information about them on their sidewall, although with somewhat smaller letters.

Motorcycle Tire Sizes Rim Width Chart

British motorcycle rims (Triumph, BSA, Norton etc.) are marked with a letter and number designation. This is helpful to know what tires you can mount on your rim based on the manufacturer’s specs.

Common Motorcycle Tire Sizes Chart

The following chart shows some common tire sizes, including their width and the diameter. Very handy when choosing which tire will fit your bike, or which motorcycle rear fender to buy to fit the tire you want to run on your new build!

Todd Muller

Todd Muller is known for his experience and knowledge of motorcycle mechanics.

How to tell if a motorcycle tire is balancing?

Motorcycle tires will also have a position designation stamped on, alerting that the tire is either for the front or rear. Another mark is a rotation arrow, designating the proper direction of rotation when the tire is mounted. This is important because tires are designed to grip the wet pavement and direct water outward from the tread design. The tread is also designed to withstand the rotational strain, so mounting in the proper direction is an important safety measure.

Why is it important to mount tires in the proper direction?

This is important because tires are designed to grip wet pavement and direct water outward from the tread design. The tread is also designed to withstand rotational strain, so mounting in the proper direction is an important safety measure. Finally, locate the tire wear symbols.

What does 67 load index mean?

A 67 load index means the tire has a 667 maximum load rating. The H speed index means the tire is rated at a maximum of 130 mph. Load and speed index maximums are very important for you to consider when purchasing tires. The higher the load number, the more weight the tire can handle. If you ride a heavyweight, touring style bike, …

How to tell if a tire is safe?

Therefore, before you buy that “super deal” at the swap meet, make sure you check the born-on date. Where do you find it? Look for DOT stamped on the tire. It’s usually followed by some letters and numbers signifying which safety standards it meets. The last four digits of that sequence give you the manufacturing date. If those numbers are 0917, it means the tire was made in September 2017. Obviously, if you find a tire with markings indicating it was manufactured six years ago or more, you should not purchase it. Tires produced prior to 2000 had only three numbers and definitely should be avoided.

How high is a bias ply tire?

The second number is the height of the tire, compared as a ratio to the width. In this case, the tire height is 90 percent of the width, or 117 millimeters high. The dash after the height designates a bias ply tire.

What does the dash after the height mean on a tire?

The dash after the height designates a bias ply tire . If the letter B appears, it signifies a belted tire, and an R means the tire is a radial. The number 16 in the sequence is the inside diameter of the tire (equal to the outside diameter of the wheel being used). This measurement is inches rather than millimeters.

What is the mark on a tire?

Another important marking on tires is the maximum air pressure. It will usually be combined with a maximum load number and the pressure is measured when the tire is cold. It does not necessarily mean you should inflate your tire to that maximum amount.

Why do motorcycle tires have sidewall codes?

Reading your motorcycle tire sidewall codes initially came about to identify the tires’ maker. But through the years, government legislation demanded safety markings be posted to help buyers know they are getting a legally approved tire.

Why are motorcycle tires important?

Our motorcycle tires are incredibly important. Not only relevant to our safety but also to our motorcycle’s handling. By design, it’s easy to imagine they come with specific compounds, approved safety ratings or markings. These codes are noted on the motorcycle tire sidewall and help riders identify not just sizes, but purchase healthy, approved and correctly certified motorcycle tires.

What is ETRTO in tire?

In Europe, the European Tyre and Rim Technical Organisation ( ETRTO) and the Tire and Rim Association (TRA) are two organisations which influence national tire standards and aim to align national tire and rim standards in Europe. An example would be “E2” – the “E” indicates that the tire conforms to ETRTO standard R75 and the “2” means that the tire was approved for this regulation by the nation of France.

What is 55 on a tire?

55 on the rear tire is the measurement from inside the bead (which sits inside the wheel rim holding the tire within it) to the top of the tire is 55% of the tires width. In this example, 55% of 180 millimetres is 99 millimetres, or 3.9 inches. Same formula for 70 on the front.

What is load index?

Load index and speed rating. The load index is the weight the tire is capable of handling when properly inflated. Most tire manufacturers show on the sidewall what that maximum load is so there is no guessing.

Why is it important to buy the right tire for a motorcycle?

Buying and using the right tire for your specific motorcycle or scooter is very important to its load, speed and overall performance.

What to check when mounting new tires?

There have been cases (usually happening in haste) when the mechanic puts the tire on in the wrong direction. Additionally, check the inflation (PSI) as like under inflation, one of the biggest mistakes people make with their tires is to exceed maximum levels and manufacturer inflation specs leading to poor handling and premature wear.

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