A Very Useful Step By Step Guide On How to Read Bike Tire Size

how to read bike tire size

Most of the tires are now marked according to the standard of the International Standard Organization (ISO) to add more markings.

It comprises two members allowed by a dish. The three digit number is very significant. It is a bead diameter with which the tire fits the rim.

See the bead diameter of you tires of the bike. If you desire to get the tire most with same bead diameter, you may fit any of the things which are different.

Initial 2 digit number is the tire section and indicates the width of the tire. The real width is less but varies according to the design and width of the rim that is fitted.

The height may correspond to the tire section, so the diameter equals the bead diameter plus twice the section.

How the circumstance and the diameter are calculated in the Tree Size Table. The size is useful for setting cycle computer and calculating gears.

Half of the bead diameter corresponds along with the distance from the center wheels of the brake block.

By this, you may see the brake will reach to a different size of rim added with your bike. Removing from 630 to 622 needs another four mm of brake reach.

Bike tire size meaning

The International Organization for Standardization (ISO) has upgraded a universal tire sizing method which removes this complexity.

ISO uses two numbers; the first one is the width of the tire or rim in mm.

The 2nd ISO number is found on the diameter of the drop seat of the rim in mm. (“B.S.D.”).

All tires carry at least an ISO number or 1 or 2 sets of numbers. The second and third set of numbers can change up to the country where the tires are being sold.

In the mentioned lists the ISO number is 37 to 622. We call this size is 700x 35 in Australia, though this refers as 28 x 1-5/8 x 1-3/8 in Northern Europe.

Bike tyre size calculator Table

ISOImperialMetricAmericanTyre Diameter Circumference
25–63027×127×1 1 / 868026.82.14
32–63027×1¼27×1 3 / 869427.32.18
28–62228×1 5 / 8 ×1 1 / 8700×28C700×32C67826.72.13
32–62228×1 5 / 8 ×1¼700×32C700×35C686272.16
37–62228×1 5 / 8 ×1 3 / 8700×35C69627.42.19
37–59026×1 3 / 8650A66426.12.09
32–54024×1 3 / 860423.81.9
28–52024×1 1 / 857622.61.81
37–50122×1 3 / 857522.61.81
37–48922×1 3 / 856322.21.77
28–45120×1 1 / 8507201.59
35–45120×1 3 / 852120.51.64
28–40620×1 1 / 846218.21.45
28–35518×1 1 / 841116.21.29
37–34916×1 3 / 842316.71.33

Which Size Tire Fits Which Size Rim?

There are various sizes of cycle or bicycle tires. To make the system worse, in the past days of cycling, every country made bicycles according to their size.

For this situation for national sizing schemes, the similar size tire may be known for different numbers in various countries.

How to Read Bike Tire Size

Different sized tires are not interchangeable with one another marked with the similar numbers.

The page size is commonly used for writing and various older sizes. Covers dozens of additional, 3rd through 6th edition, antique sizes Sutherland’s Handbook for Bicycle Mechanics.

The sixth edition is found in CDROM for Sutherland’s Better bike stores having a  copy.

Traditional Sizing Systems

The conventional sizing procedures are dependent on the measurement of the outer diameter of a tire. It is measured in inches or millimeters.

Unluckily revolution of rims and tire has made the measurement lose contact along with reality.

How to Read Bike Tire Size

Here is the way to work: begin with a 26×2.125 size which becomes popular for heavyweight balloon tire bike for the late 30s and remains common beach cruiser bike.

The real diameter of the tire is 26 inch. Some people are dissatisfied with this size and desire to have something better, faster and lighter.

The industry is ready to make middleweight tires indicated 26×1.75 to fit the similar rims.

Though they are known as 26 inches, the tire is 25 5/8 inch, not 26. The similar rim size is adopted by the early pioneers of west coast clunkers and may standard for the mountain bikes.

For the thirst of the market, you may obtain tire so narrow as 25mm to adjust the rims. You may wind up having 26-inch tire which more same 24 7/8 inch real diameter.

Bike Tire Size

What is the type of the current tire size? Simply check the tire sidewall.

Mountain bike tires

In a mountain bike tire, you will see a lot of pairing seems 27.5×2.0. It may be about the outer tire diameter (27.5″) by the width(2″).

A cross country bike has a tire measuring 1.9 inches to 2,25-inch width range. All mountain bikes have tires 2.25 inch to 2.4-inch width.

But the downhills bike can withstand the abuse of drops as well as a rock garden, are decorated with tires ranging up to3.5 inch wide.

Road touring and racing tires

In Road bike, you can see lots of pairing like 700X23.

The 1st number is the size that roughly corresponds to the outer diameter of the tire into millimeters. The second one expresses the true width of the tire in millimeters.

There are some exceptions in 650s and the 27-inch size used on previous bikes.

How to Read Bike Tire Size

The letter to the end of the tire size is a throwback to the French system as the letter a, b and c use for various inner tire diameters. Sometimes these letters seem to come in tire sizes.

Especially, any 700 tire nowadays is similar to the size of old 700c tire. You see 650b, that is same of today’s 27.5-inch mountain bike tire, and 650c, that is little smaller inner diameter instead of the 560b tire and easily got into a few road bikes.

Most racers like to use tire 700 width range from 18 to 23 mm to the narrowest alternatives.

People who like for epic tour likely to be riding tires width range from 25 to 28mm for a comfort and stability.

Cyclocross tires

There are small knobby but are made with narrow width 700 sizes to adjust the fit the geometry of cyclocross racing frame.


29er mountain bike runs a knobbier and wider variation of the 700 tires applied for cyclocross but may seem typical mountain bike tire.

It is made to roll easily over the technical trail section and by sand and mud. Climbing traction and cornering will be better for increased contact by the trial.

BMX tires come in a twenty-inch diameter.

What are Butyl rubber tire?

Butyl is sturdy and resistant, and you will find lightweight models for people who are searching for weight savings – that the Specialized Turbo variety and Continental Supersonic tubes are all trendy models.

What are the differences between Latex and Butyl rubber tire?

Latex rubber tire provides marginally enhanced handling features – since latex rubber is somewhat more flexible than conventional butyl rubber, and the tubes adapt rapidly into the tires shifting shape while cornering and on effects. Latex tubes usually have a thinner wall, offering clear weight savings. The Latex tire also have been demonstrated in many evaluations to get lower rolling resistance, which makes them quicker.

Are there any drawbacks of Latex rubber tire?

Regardless of the benefits, it’s essential to recognize the defects of Latex. Latex rubber responds poorly to contact with a few oils and greases so needs to be dealt with carefully from the workshop. Additionally, Latex is much more gas permeable than butyl rubber and, consequently latex rubber tire doesn’t grip the atmosphere so long as butyl established conduits and need more regular inflation, in addition to being somewhat brittle and easy to tear when adding. Despite their flaws, latex tubes are slightly quicker and lighter, therefore worth the investment if you are planning to become more aggressive.

What can I use for puncture protection?

The sealant is acceptable for use with internal tubes with elimination cores. By massaging the sealant to the tire, it can rapidly seal modest holes by massaging and forming a clot within the pit in regards into contact with the atmosphere. It is going to readily seal the kind of holes that you might get from road debris or thorns. Puncture protection is remarkably helpful for commuting and mountain biking trails.


Be sure you can easily reach the brake levers along with gear shifter normally after removing the position of your handlebars.

Be confirming not to kink gear or brake cables if you adapt handlebars.

When you see the altering of handlebar position is difficult, you can think to change the height of the seat.

Watch: How to Read Bike Tire Size

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1 thought on “A Very Useful Step By Step Guide On How to Read Bike Tire Size”

  1. It won’t work very well at all. Superglue, unlike rubber glued with rubber cement, doesn’t stretch. It will probably open up again as soon as you inflate the tire. You’d probably have to replace the tube after that as a proper patch wouldn’t stick to the dried superglue.
    So I definitely say that your tips are too effective and work it out. Thank you.

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