Tire size can be confusing. Some numbers on the sidewall are listed in millimeters while others are inches. Plus, the right size for your car, truck, or trailer can differ depending on where and how you drive.
You can see your original equipment tire size in your owner’s manual or on the placard generally located on the driver’s side door jam. This is the sizing recommended by the vehicle manufacturer.
If you’re interested in switching out your tires for a different look or performance, a good place to start is the numbers and other indicators on your existing tires’ sidewall. Next, have a tire professional help you determine a tire size range that will fit your vehicle and driving needs.
Here’s what those numbers and indicators on the sidewall indicate and how to understand them:
A: TIRE TYPE The first letter in the code tells you what class of tire it is.
P stands for passenger vehicle tire. P-class tires include cars, SUVs, crossovers, minivans and smaller pickup trucks.
LT means light truck tire, designed for vehicles that are capable of carrying heavy loads, towing trailers, or for those looking for an extra heavy duty option. These are often equipped on three-quarter or 1 ton trucks and SUVs.
ST stands for Special Trailer. These tire sizes are meant for trailers, including fifth wheels and other travel trailers, as well as boat and utility trailers.
If there’s no letter before the first number, you have a metric tire most commonly referred to as European size. It’s also measured in millimeters but may have a different load capacity than a P or LT tire.
B: TIRE WIDTH The three-digit number following the letter is the tire’s width (from side to side, looking at the tire head on) in millimeters. This may also be referred to as the section width.
C: ASPECT RATIO The forward slash separates the tire width number from the two-digit aspect ratio. The bigger the aspect ratio, the higher/taller the tire’s sidewall, or “profile” as it’s sometimes called.
The aspect ratio is indicated on the tire sidewall as a percentage. It’s the height of the sidewall measured from wheel rim to top of the tread, expressed as a percentage of tire width.
In this example, the aspect ratio is 65, meaning the sidewall is 65 percent as high as the tire is wide. To get the sidewall height, take the tire width of 215 mm and convert it to inches (8.46). Then multiply this by 65% (.65). This gives you an answer of 5.5, the sidewall height in inches.
D: CONSTRUCTION TYPE This single letter tells you about the internal construction of the tire.
R is for radial tires, the industry standard for most tires today. They have better road grip, lower rolling resistance for better gas mileage, ride comfort and durability than previous generations of tires.
In a radial tire, the plies — layers of strong cords made of a blend of polyester, steel and fabric and coated with rubber — are laid perpendicular to the direction of travel.
D is for tires built with diagonal (crisscrossed) plies, called bias-constructed tires. They are also called conventional, x-ply, or cross-ply tires. Some motorcycle and trailer tires still use this internal construction.
Some run-flat tires are identified with an F followed by the type of internal construction.
E: WHEEL DIAMETER This two-digit number specifies wheel diameter in inches. It’s the distance between the two bead seat areas (where a tire gets tightly sealed onto the wheel).
F: LOAD INDEX The two-digit or three-digit number that follows the gap specifies tire load index. The load index symbol indicates how much weight a tire can support, based on the following standard chart. In our example, the load index is 89, which indicates the tire has a load capacity of 1,279 pounds, when inflated to the tire’s maximum air pressure rating.
G: SPEED RATING The last letter is the tire speed rating. This indicates the top speed it’s safe to travel at for a sustained amount of time. A tire with a higher speed rating can handle heat better and provide more control at faster speeds. The maximum operating speed of a vehicle is no more than the lowest speed rating of all tires mounted on the vehicle. (Of course, you should always abide by speed limits for safer driving.) Speed rating is usually, but not always, a single letter (see the chart).
Below you will find several charts that will help you understand tire sizing numbers, including a load index chart and speed rating chart.
A tire size calculator is a quick way to see whether the tire size you’re considering will likely fit your car, SUV, sports car, light truck or crossover.
But remember that is only an estimate. It’s important to stay within the sizing tolerances of your vehicle.
Tires that are the wrong size could cause some pull in the steering wheel, rub against the suspension or body of your vehicle, reduce clearance on hills, or result in a stiffer or noisier ride.
If you’re considering mounting a different tire size on your vehicle, check with a tire expert. Find out whether the tires and wheels you have your eye on are the right fit for your vehicle’s suspension, gearing, and bodywork. And ask how any differences in revolutions per mile, tire speed, load index, and speed rating will affect your ride quality and vehicle performance.
See how new tires and rims will look on your car or truck using our Virtual Wheels simulator, available at any Les Schwab.
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When shopping for tires online, you’ll notice the terms load index, load range, and speed rating included within the technical specifications. (You can find these numbers and letters on your existing tires, located after the size of the tire.
) Understanding the meaning of load index and load range can help you find the right tire for your vehicle and your needs. As always, the experts at Les Schwab can answer all of your questions about what tires are right for you, but in this quick article, we’ll cover some of the basics of these indicators.
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The load index of a tire is a number that correlates to the maximum safe carrying capacity of the tire when it’s inflated to its maximum pressure. Higher load index ratings mean your tires will be able to handle a heavier load. In this example, there are two numbers. The higher number (load index) is for single rear-wheel applications. The lower number is for dual-wheel applications. This indicates its load-carrying capacity when inflated to its maximum pressure. Remember, air pressure is what carries the load in a tire. You can find each tire’s carrying capacity with the chart below.
| LOAD INDEX |
LOAD (lbs) |
LOAD INDEX |
LOAD (lbs) |
LOAD INDEX |
LOAD (lbs) |
|---|---|---|---|---|---|
| 65 | 639 | 94 | 1477 | 123 | 3417 |
| 66 | 661 | 95 | 1521 | 124 | 3527 |
| 67 | 677 | 96 | 1565 | 125 | 3638 |
| 68 | 694 | 97 | 1609 | 126 | 3748 |
| 69 | 716 | 98 | 1653 | 127 | 3858 |
| 70 | 739 | 99 | 1709 | 128 | 3968 |
| 71 | 761 | 100 | 1764 | 129 | 4079 |
| 72 | 783 | 101 | 1819 | 130 | 4189 |
| 73 | 805 | 102 | 1874 | 131 | 4299 |
| 74 | 827 | 103 | 1929 | 132 | 4409 |
| 75 | 853 | 104 | 1984 | 133 | 4541 |
| 76 | 882 | 105 | 2039 | 134 | 4674 |
| 77 | 908 | 106 | 2094 | 135 | 4806 |
| 78 | 937 | 107 | 2149 | 136 | 4938 |
| 79 | 963 | 108 | 2205 | 137 | 5071 |
| 80 | 992 | 109 | 2271 | 138 | 5203 |
| 81 | 1019 | 110 | 2337 | 139 | 5357 |
| 82 | 1047 | 111 | 2403 | 140 | 5512 |
| 83 | 1074 | 112 | 2469 | 141 | 5677 |
| 84 | 1102 | 113 | 2535 | 142 | 5842 |
| 85 | 1135 | 114 | 2601 | 143 | 6008 |
| 86 | 1168 | 115 | 2679 | 144 | 6173 |
| 87 | 1201 | 116 | 2756 | 145 | 6393 |
| 88 | 1235 | 117 | 2833 | 146 | 6614 |
| 89 | 1279 | 118 | 2910 | 147 | 6779 |
| 90 | 1323 | 119 | 2998 | 148 | 6944 |
| 91 | 1356 | 120 | 3086 | 149 | 7165 |
| 92 | 1389 | 121 | 3197 | 150 | 7385 |
| 93 | 1433 | 122 | 3307 |
| LOAD INDEX | LOAD (lbs) |
|---|---|
| 65 | 639 |
| 66 | 661 |
| 67 | 677 |
| 68 | 694 |
| 69 | 716 |
| 70 | 739 |
| 71 | 761 |
| 72 | 783 |
| 73 | 805 |
| 74 | 827 |
| 75 | 853 |
| 76 | 882 |
| 77 | 908 |
| 78 | 937 |
| 79 | 963 |
| 80 | 992 |
| 81 | 1019 |
| 82 | 1047 |
| 83 | 1074 |
| 84 | 1102 |
| 85 | 1135 |
| 86 | 1168 |
| 87 | 1201 |
| 88 | 1235 |
| 89 | 1279 |
| 90 | 1323 |
| 91 | 1356 |
| 92 | 1389 |
| 93 | 1433 |
| 94 | 1477 |
| 95 | 1521 |
| 96 | 1565 |
| 97 | 1609 |
| 98 | 1653 |
| 99 | 1709 |
| 100 | 1764 |
| 101 | 1819 |
| 102 | 1874 |
| 103 | 1929 |
| 104 | 1984 |
| 105 | 2039 |
| 106 | 2094 |
| 107 | 2149 |
| 108 | 2205 |
| 109 | 2271 |
| 110 | 2337 |
| 111 | 2403 |
| 112 | 2469 |
| 113 | 2535 |
| 114 | 2601 |
| 115 | 2679 |
| 116 | 2756 |
| 117 | 2833 |
| 118 | 2910 |
| 119 | 2998 |
| 120 | 3086 |
| 121 | 3197 |
| 122 | 3307 |
| 123 | 3417 |
| 124 | 3527 |
| 125 | 3638 |
| 126 | 3748 |
| 127 | 3858 |
| 128 | 3968 |
| 129 | 4079 |
| 130 | 4189 |
| 131 | 4299 |
| 132 | 4409 |
| 133 | 4541 |
| 134 | 4674 |
| 135 | 4806 |
| 136 | 4938 |
| 137 | 5071 |
| 138 | 5203 |
| 139 | 5357 |
| 140 | 5512 |
| 141 | 5677 |
| 142 | 5842 |
| 143 | 6008 |
| 144 | 6173 |
| 145 | 6393 |
| 146 | 6614 |
| 147 | 6779 |
| 148 | 6944 |
| 149 | 7165 |
| 150 | 7385 |
On some tires, you’ll see a load range indicator on the sidewall, as shown here.
Load Range is an older measure of tire carrying capacity equivalent to
ply rating. The ply rating isn’t directly tied to the number of plies used in construction, so we recommend using Load Index when
appropriate. Load ranges are arranged in alphabetical order starting with the letter “A”. The ply ratings (load range) combined with the tire size tell you the tire load capacity.
The load range on replacement tires must meet or exceed the recommendation on your vehicle’s door placard or owner’s manual. It can be higher than recommended but never lower.
| LOAD RANGE | PLY RATING |
|---|---|
| A | 2 |
| B | 4 |
| C | 6 |
| D | 8 |
| E | 10 |
| F | 12 |
Les Schwab Tip: Some cars, including electric vehicles, may require tires with a higher load range due to weight with and without passengers.
If this seems confusing. Don’t worry. The pros at Les Schwab will show you all of your options, including the size, load range, and load index you need for work, weekends, or your daily commute.
Nikolaev bicycle shop "Sportek"
Published: 01/27/2017
Edited: 06/01/2021
Sooner or later, almost every cyclist faces the question of replacing the rubber on the wheel or the cameras for them.
The easiest way, of course, is to look at the size of the tire currently installed on the bike (it is written on the side of it), and look for exactly the same. On some rims, their landing diameter and width are also written.
In life, everything is always a little more complicated and it often happens that the tire you like has a marking that is not entirely clear or does not match the marking on your rubber. Sometimes it is necessary to replace the old bicycle rubber, which has served for many years, with a more modern one.
What to do? You can’t put a tire on a bike over the Internet, but you don’t want to pay money just like that.
In this article, we will try to help you understand the markings on bicycle tires and find out which of them are interchangeable.
The first thing you need to know when choosing a tire is the size of the wheels.
They are usually measured in inches, but sometimes in mm. There are not very many of them and the most common are 16, 18, 20, 24, 26, 27.5, 28, 29.
At the same time:
Further, what else you need to know is seat size (diameter) of the rim or BSD (English Bead Seat Diameter). It is the most important and determines the interchangeability of tires. If this number matches at the rim, tire, or tube, then that tire or tube fits those rims. And if the width of the new rubber can be changed, then the landing size will not change much.
If the size (numbers in mm) is written on the wheel (rim), for example, as in the photos above, they accurately indicate the fit size of the rim and its width, which is the main data for selecting the inner tube and tire for the wheel.
There are several types. The confusion in the designation of sizes began in the middle of the 20th century, and today Great Britain and France use their own designations for marking.
Previously, the sizing system was based on the outside diameter of the tires. It was measured in inches (24", 26", 28") or in millimeters (500, 650, 700, etc.).
Over time, this system lost its meaning, because different products with the same outer diameter wheels (together with the height of the tire) did not match the inner diameter (rim diameter) on which this tire was put on.There were also marketing moves of manufacturers, and the accuracy of translation and rounding of measurements in inches is lower than in millimeters.0003
To overcome these confusions and bring all sizes to the same standard, the International Organization for Standardization (ISO - International Organization for Standardization) has developed a universal system for designating tire sizes - ISO 5775 .
This system was previously known as " ETRTO ". It was proposed by the organization of the same name: ETRTO (European Tire and Rim Technical Organization or in Russian: "European technical organization for rims and tires").
At first it was in the form of a number and a letter, for example, 700C - 700 the outer diameter of the tire is in mm. The letter determined the width from "A" - the narrowest to "D" - the widest.
Now the marking has acquired a more modern look. For example: 700 x 35C. Here the outer diameter of the tire is 700 mm and its width is 35 mm. The letter at the end indicates the inner (landing) diameter. In this case, "C" is 622 mm.
Those. first inner diameter tire (rim size ) - 533 mm, and then its width - 37 mm. (instruction for Soviet bicycles: "SPORT", "Salyut")
Note a very important nuance and paradox in inch sizes. Tire sizes can be specified as a decimal fraction, such as 26x1.75, or as a simple fraction, such as 26x1 3/4.
Mathematically, these fractions are equal: 1.75 = 1 3/4.
But, in terms of fit size and tire width in millimeters, this is not always the case, and the most unpleasant thing is that tires with such dimensions can be not interchangeable with .
And this circumstance should always be taken into account when purchasing a new bicycle tire.
In the table below, we have tried to collect the most common tire size designations in different systems and show their compatibility.
Perhaps not all dimensions encountered in life were taken into account, but if you have a tire with dimensions not listed in the table, try to estimate its dimensions based on similar nearest or similar dimensions.
| Rim bore size in mm according to ISO | Tire size in plain and decimal inches | French tire size | Tire size in mm according to ISO (width - bore) | Explanations |
| 681 | 22-681 | Sports track bike B-64 "Record" KhVZ (1958) | ||
| 642 | 28 x 1 5/8 x 1 1/2 | 700-28A | 28-642 | Obsolete size |
| 28 x 1 3/8 | 700-35A | 37-642 | ||
| 635 | 28 x 1 1/2 x 1 1/8 | 700-28B | 32-635 | American, English, Danish, Chinese, Indian road models |
| 28 x 1 1/2, 28 x 1 1/2 x 1 5/8 | 700-38B, 700B Standard | 40-635 | ||
| 28 x 1 5/8 x 1 1/2 | 44-635 | |||
| 630 | 27 x 7/8 | 22-630 | Road bikes, including older models | |
| 27 x 1 | 25-630 | |||
| 27 x 1 1/8 | 28-630 | |||
| 27 x 1 1/4 | 32-630 | |||
| 27 x 1 3/8 | 37-630 | |||
| 27 x all options | ||||
| 622 | 29 x all variants | 700C | This size was invented by marketers for tires with a bore diameter of 622 mm. They differ from 28 only in tire height. | |
| 28 x decimal | 700C | For 622 mm tires | ||
| 28 x 3/4 | 700-18C 700x18C | 18-622 | ||
| 700-19C 700x19C | 19-622 | |||
| 28 x 3/4 | 700-20C 700x20C | 20-622 | ||
| 28 x 1 28 x 7/8 | 700-23C 700x23C | 23-622 | ||
| 28 x 1 | 700-25C 700x25C | 25-622 | ||
| 28 x 1 1/8, 28 x 1 5/8 x 1 1/8 | 700-28C 700x28C | 28-622 | ||
| 28 x 1.20 | 700-30C 700x30C | 30-622 | ||
| 28 x 1 3/4, 28 x 1.5 | 700x38C 700-40C | 40-622 | Road bikes: "Ukraine", "Minsk", "Sura", "Velta", "Aist" (111-321, 111-322) | |
| 28 x 1 1/2, 28 x 1 5/8 x 1 3/8 | 700C 700x35C 700x38C | 35-622 | Road bikes: "Ukraine", "Minsk", "Sura", "Velta", "Aist" | |
| 27 x 1 1/4, 28 x 1 5/8 x 1 1/4 | 700-32C 700x32C | 32-622 | Road and sports touring bikes, "Tourist", "Sport", "Sputnik" | |
| 28 x 1 5/8 x 1 1/4 | Obsolete Canadian designation F13 | |||
28 x 1. 4 | 700-35C 700x35C | 35-622 | Road bikes | |
| 28 x 1.5 | 700x38C 700-38C 700-40C 700x40C | 40-622 | ||
| 28 x 1 3/8 x 1 5/8 | 37-622 | |||
| 28 x 1.6 | 700-42C 700x42C | 42-622 | ||
| 28 x 1.6 | 700-44C 700x44C | 44-622 | ||
| 28 x 1 5/8 x 1 3/4 | 700-45C 700x46C | 45-622 | ||
| 28 x 1.75, 28 x 1 5/8 x 1 3/4 | 700-47C 700x47C | 47-622 | ||
| 28 x 2.00 | 700-50C 700x50C | 50-622 | ||
| 600 | 22 (23, 24, 25, 27, 28, 30)-600 | Old Soviet sports and track bikes | ||
| 599 | 26 x 1.25, 26 x 1.375 | 32-599 | Very old American light bicycles. | |
| 26 x 1 7/8 | 47-599 | ZiF (Penza) 190-535 "Samson" | ||
| 597 | 26 x 1 1/4 (EA1) (England) | 32-597 | English old sports and club bikes. | |
| 26 x 1 3/8 (S-6) | 37-597 | Light bicycles of the American firm Schwinn. | ||
| 590 | 26 x 1 1/8 | 28-590 | Soviet bicycles ZiF (Penza) "Diana", "Prima", "Turn", "Relay", "Sura", "Breeze", "Temp" American and English 3 and 10 speed. | |
| 26 x 1 1/4 | 32-590 | |||
| 26 x 1 3/8 (E.A.3) (England) | 650A | 35-590 | ||
| 26 x 1 3/8 | 650-35A 650x35A | 37-590 | ||
| 26 x 1 5/8 | 44-590 | |||
| 587 | 700D | Old size on some GT models | ||
| 584 | 27. 5 x 1.50 | 650x38B | 40-584 | French road bikes, touring bikes with cargo, tandems, some Raleigh (USA), old Schwinn mountain bikes |
| 26 x 1 1/2 | 650B | 37-584 | ||
| 27.5 x 1.5 | 40-584 | |||
| 27.5 x 1.65 | 44-584 | |||
| 27.5 x 1.75 | 47-584 | |||
| 27.5 x 2 | 52-584 | |||
| 27.5 x 2.1 | 54-584 | |||
| 27.5 x 2.25 | 57-584 | |||
| 27.5 x 2.3 | 60-584 | |||
| 27.5 x 2.4 | 62-584 | |||
| 27.5 x 2.8 | 70-584 | |||
| 571 | 26 x 3/4 | 650x20C | 20-571 | Triathlon, time trial, small road bikes, some French Peugeot bikes. |
| 26 x 7/8 | 650x23C | 23-571 | ||
| 26 x 1 | 650C | 23-571 | ||
26 x 1. 75 | 47-571 | |||
| 26x1 3/4 (S-7) | Road Schwinn | |||
| 559 | 26 x 1.0 | 25-559 | Most mountain bikes. Classic landing diameter for 26 wheels. | |
| 26 x 1.25 | 32-559 | |||
| 26 x 1.35 | 35-559 | |||
| 26 x 1.4 | 37-559 | |||
| 26 x 1.5 | 40-559 | |||
| 26 x 1.6 | 44-559 | |||
| 26 x 1.75 26 x 1.75 x 2 | 47-559 | |||
| 26 x 1.95 | 50-559 | |||
| 26 x 2.00 | 52-559 | |||
| 26 x 2.10 | 54-559 | |||
| 26x2.15 | 55-559 | |||
26 x 2. 25 | 57-559 | |||
| 26 x 2.3 | 60-559 | |||
| 26 x 2.4 | 62-559 | |||
| 26 x 3.0 | 75-559 | |||
| 26x3.7 | 95-559 | |||
| 26 x 4.00 | 100-559 | |||
| 26x4.5 | 115-559 | |||
| 26x4.8 | 120-559 | |||
| 547 | 24x1 1/4 | English children's and American firm Schwinn | ||
| 24x1 3/8 (S-5) | Schwinn American children's bicycles | |||
| 540 | 24 x 1 1/8 | 600A | 28-540 | Children's English and European bicycles, most wheelchairs |
| 24 x 1 1/4 | 32-540 | |||
| 24 x 1 3/8(E-5), 24 x 1 3/8 A | 37-540 | |||
| 533 | 24 x 1 1/2 | 37-533 | "Salute", "Altair", "Ervi", "Eaglet", "Erelyukas", "Swallow" ("Kregzdute", "Kregzhdute" - Siauliai bicycle factory "Vairas" Lithuania). Be careful when replacing as not all 24" tires will fit 533 wheels. | |
| 531 | 24 x 1 5/8 x 1 1/2 | 44-531 | ||
| 520 | 24x1 | 25-520 | Road wheels for children's bikes | |
| 507 | 24 x 1.5 | 40-507 | Children's mountain. "Salute", "Altair", "Ervi" | |
| 24 x 1.75 | 47-507 | |||
| 24 x 1.95 | 50-507 | |||
| 24 x 2.0 | 51-507 | |||
| 24 x 2.125 | 54-507 | |||
| 24 x 2.25 | 57-507 | |||
| 24 x 2.35 | 60-507 | |||
24 x 2. 5 | 62-507 | |||
| 24 x 2.6 | 65-507 | |||
| 24 x 2.75 | 70-507 | |||
| 24 x 3.0 | 75-507 | |||
| 501 | 22 x 1.0 | 25-501 | European bikes | |
| 22 x 1 1/4 | 32-501 | |||
| 22 x 1 3/8 | 37-501 | |||
| 490 | 550-28A | 28-490 | European Road Kids Bikes | |
| 22 x 1 3/8 x 1 1/4 | 550-32A | 32-490 | ||
| 22 x 1 3/8 | 550-35A | 37-490 | ||
| 489 | 22 x 1.0 | 25-489 | European bikes | |
| 22 x 1 3/8 | 37-489 | |||
| 22 x 1 3/8 x 1 1/4 | 40-489 | |||
22 x 2. 00 | 50-489 | |||
| 457 | 22 x 1.75 to 2.125 | Children's bicycles | ||
| 451 | 20 x 1 1/8 | 28-451 | BMX for light riders, light children's bikes, some ligerades. Wheels on some types of wheelchairs. | |
| 20 x 1 1/4 | 30-451 | |||
| 20 x 1 3/8 | 37-451 | |||
| 445 | 20 x 1 1/4 | 30-445 | "Schoolboy" (old Soviet models) | |
| 440 | 500-28A | 28-440 | European folding, children's bikes | |
| 500-35A | 37-440 | |||
| 20 x 1 1/2 | 500-38A | 40-440 | ||
| 438 | 20 x 1 3/8 | 37-438 | European bikes | |
| 20 x 1 3/8 1 1/2 | 40-438 | |||
| 432 | 20 x 2 1/2 | 40-432 | European bikes | |
| 428 | 20 x 2. 00 | 54-428 | European bikes | |
| 419 | 20 x 1 3/4 | Schwinn American children's bicycles | ||
| 406 | 20 x 1.25 | 32-406 | Most BMX bikes, kids and folding models. "Venta" (folding model 175-811). "Stork" (folding, model 113-322) "Tisa-2", "Cross", "KAMA", "DESNA", "Schoolnik", "Velta Kama", "Dubisa" (Siauliai bicycle factory), "Eureka" and other folding and old Soviet models. Folding "Mustang" | |
| 20 x 1.35 | 35-406 | |||
| 20 x 1 3/4 20 x 1.5 | 40-406 | |||
| 20 x 1.75, 20 x 1.75 x 2 | 47-406 | |||
| 20 x 1.95 | 50-406 | |||
| 20 x 2.00 | 54-406 | |||
20 x 2. 125 | 57-406 | |||
| 20 x 2.35 | 60-406 | |||
| 20 x 2.5 | 62-406 | |||
| 20 x 2.6 | 65-406 | |||
| 20 x 2.75 | 70-406 | |||
| 20 x 3.0 | 75-406 | |||
| 390 | 18 x 1 1/8 | 450-28A | 28-390 | Children's European bikes |
| 18 x 1 3/8 | 450-35A | 37-390 | ||
| 450-55A | 55-390 | |||
| 387 | 18 x 1 1/2 | 37-387 | Children's European bikes | |
| 369 | 17 x 1 1/4 | 32-369 | Bicycles Alex Moulton | |
| 355 | 18 x 1 1/8 | 28-355 | Children's bicycles | |
18 x 1. 25 | 32-355 | |||
| 18 x 1.35 | 35-355 | |||
| 18 x 1.5 | 40-355 | Birdy folding bikes. | ||
| 18 x 1.6 | 42-355 | Children's bicycles | ||
| 18 x 1.75 | 47-355 | |||
| 18 x 1.95 | 50-355 | |||
| 18 x 2.0 | 54-355 | |||
| 18 x 2.125 | 57-355 | |||
| 349 | 16 x 1 1/8 | 28-349 | Old Moulton, Brompton and other folding bicycles, ligerade front wheels, children's bicycles. | |
| 16 x 1 1/4 16 x 1.25 | 32-349 | |||
| 16 x 1.35 | 35-349 | |||
| 16 x 1 3/8 | 37-349 | |||
| 340 | 400-30A | 28-340 | Children's European bikes | |
| 16 x 1 3/8 x 1 1/4 | 400-32A | 32-340 | ||
| 16 x 1 3/8 | 400-35A | 37-340 | ||
| 16 x 1 5/8 | 400A | 44-340 | ||
| 335 | 16 x 1 3/8 | Children's Polish bicycles | ||
| 330 | 16 x 1 1/2 | 400-38B | 40-330 | Children's bicycles |
| 317 | 16 x 1 3/4 | Schwinn American children's bicycles | ||
| 305 | 16 x 1. 5 | 40-305 | Children's bicycles, folding, touring and some ligerades. | |
| 16 x 1.75 | 47-305 | |||
| 16 x 1.95 | 50-305 | |||
| 16 x 2.0 | 54-305 | |||
| 16 x 2.125 | 57-305 | |||
| 16 x 2.5 | 62-305 | |||
| 298 | 14 x 1 1/4 | 350-32A | 32-298 | Carriages, children's bikes, balance bikes |
| 288 | 14 x 1 3/8 | 350A, 350-35A | 37-288 | Children's bicycles, balance bikes |
| 14 x 1 5/8 | 350-38A | 40-288 | ||
| 14 x 1 5/8 x 1 3/8 | 350-42A | 44-288 | ||
| 14 x 1.75 | 47-288 | |||
| 279 | 14 x 1 1/2 | 350-38B | 40-279 | Children's bicycles, balance bikes |
| 254 | 14 x 1. 5 | 40-254 | Children's bicycles, balance bikes | |
| 14 x 1.75 | 47-254 | |||
| 14 x 2 | 54-254 | |||
| 239 | 12 1/2 x 1 3/8 x 1 1/4 | 300-32A 300x32A | 32-239 | Children's bicycles, balance bikes |
| 205 | 12 1/2 x 2 1/4 | 56-205 | Children's bicycles "KVD", balance bikes, sometimes suitable for baby carriages ("Dutik" tires) | |
| 203 | 12 x 1.75 12 1/2 x 1.75 12 1/2 x 1.9 | 47-203 | Small children's bicycles, balance bikes, baby carriages | |
| 12 x 1.95 | 54-203 | |||
| 12 x 2.0 | 50-203 | |||
| 12 x 2.125, 12 1/2 x 2 1/4 R | 57-203 | |||
| 12 1/2 x 2 1/4 | 62-203 | |||
| 176 | 55-176 | Tires for tricycles, scooters, balance bikes for small children, wheelbarrows and carts, prams | ||
| 152 | 10 x 2 | 54-152 | ||
| 137 | 8 x 1 1/4 | 32-137 |
29 tires differ from 28 only in height. Tire width selection is more flexible than rim diameter.
Rim widths are measured and marked in millimeters as shown in the figure at the beginning of the article.
How to measure the width of the rim is described in a separate article here.
| Rim width in mm | Tire width in mm and inches | Bicycle type |
| 13 | 18 - 25 mm (1") | road and cyclocross models |
| 15 | 23 - 32 mm (1" - 1.25") | |
| 17 | 25-37 mm (1" - 1.5") | light cross-country and hybrid models |
| 18 | 28 - 44 mm (1.1" - 1.75") | heavy cross-country and hybrid models |
| 19 | 28 - 60 mm (1.1" - 2.35") | MTB (mountain bikes, mountain bikes) |
| 20 | 28 -47 mm (1. 1" - 2") | cycling and light extreme |
| 21 | 35 - 50 mm (1.4" - 2") | |
| 23 | 40 - 50 mm (1.5" - 2.1") | extreme cycling |
| 25 or more | 44 - 57 mm (1.75" - 2.25") | |
| 32 | 75 mm (3") and over |
This table shows guide data for a medium bike. Use it not as a dogma, but as a guideline for selection.
Some manufacturers give their own tables for the tires they produce, according to which they need to be selected for their wheel.
The tire width affects rolling and grip. The wider - the better the grip, cornering control, but the worse the roll.
It is considered optimal if the width of the tire is 1.5-2.1 times wider than the inner width of the rim. It is possible and 2.5 times, but this is already an amateur.
The tire-to-rim width ratio affects the tire's cornering behavior. Too wide tires mounted on a narrow rim can simply break. will have a pear-shaped profile.
Further, if the wheel is equipped with toothy rubber, then the side spikes on the tread will not be where they should be for sure grip in the turn.
With wide tires on a narrow rim, the side studs will be too high and will not hold properly in the turn.
On narrow tires with a wide rim, the spikes will be from below and with a good slope, the bike will ride on the sidewall, and she is bald.
Below is the famous table compiled by Georg Boeder of tire and rim width recommendations
fractional inches) here.
Comments (131)
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The standard designation is based on the outside diameter of the tire.
This size is usually expressed in either inches (26", 27", etc.) or millimeters (650, 700, etc.).
Unfortunately, the evolution of rims and tires has led to the fact that this marking no longer matches the actual diameter. The history of this confusion dates back to the 30s of the last century, when heavy thick tires "baluners" measuring 26 x 2.125 were popular, which are still installed on some pleasure and beach bikes. The outer diameter of such a wheel is very close to 26". Many cyclists, however, were not completely satisfied with the characteristics of these wheels and wanted something faster and lighter. The industry responded to their request by producing lighter and narrower tires that fit the same rim, and designated 26 x 1.75.
Although these tires continued to be called "26" tires, their actual diameter was 25 5/8", not 26". Later, the same rim size was used by the pioneers of the US West Coast mountain bike, which remains the standard size for mountain bikes today.
The market began to dictate its terms to manufacturers, and tires with a width of only 25 millimeters for the “26-inch” rim appeared on sale. In fact, the outer diameter of the wheel was 24 7/8".
In the standard tire size designation, the second number or letter code indicates its width. For example, 26 x 1.75; 27 x 1 1/4; 650B; 700C.
Please note that in the standard inch tire sizing system, its width can be indicated as a decimal fraction (26 x 1.75) or a simple one (26 x 1 3/4). Although in a mathematical sense the width of these tires is equivalent, in practice they are incompatible. This fact often leads to the fact that an insufficiently competent buyer purchases a tire of the wrong size.
In general, it's hard to come up with a generalized rule for tire sizes, but I was able to identify one pattern:
If the size of the two tires taken coincides mathematically, but one of them is expressed as a decimal and the other as a simple fraction, these two tires are definitely incompatible.
In a fierce competition, the accuracy of information provided by manufacturers often suffers. Let's say you're looking for high quality 700-25 tires. Naturally, you study both catalogs and advertisements to find the lightest tires in this size. If, for example, Pepsi Tire and Coke Tire produce tires using the same technology and roughly the same quality, but Pepsi labels a 24mm tire as 700-25, it will weigh less than a fairly labeled 700-25 tire from Coke. This marketing technique gives Pepsi a tangible advantage. In response, Coke is releasing the even lighter 700-23 tire, again labeling it 700-25.
In the 70s and 80s, this marketing ploy was very popular. As a result, the situation got completely out of control, and all manufacturers still had to take their heads and start indicating only the true dimensions of their products.
The International Organization for Standardization (ISO) has developed a universal tire size designation system in order to avoid errors and various incompatibility issues.
This system was originally known as the "ETRTO system", developed by the company of the same name (European Tire and Rim Technical Organization).
The ISO system uses two numbers. The first is the width of the tire or rim in millimeters. The actual width of the tire depends on the width of the rim, which is measured along the inner beads (see figure).
The second ISO number is the most important - indicates the rim seat diameter (BSD, from the English "Bead Seat Diameter") in millimeters. It determines the interchangeability of tires. If this number matches the rim and tire, then they are compatible.
For example, a 700 x 20 C road tire is ISO 20-622; hybrid tire 700 x 38 - like 38-622. Due to the difference in width, they may not be perfect replacements for each other, but most importantly, any rim that fits a 20-622 tire will also fit a 38-622 tire.
Also, it is important to consider that the width of the tire should be 1.45-2 times wider than the inner width of the rim.
If you deflate a tire and measure its bead width, the result is approximately 2.5 times the ISO value.
The following tables show the relationship between US standard sizes and ISO bore.
| 29" | 622 | Accepted name introduced by marketers. Refers to tires with a 622 mm bore ("700c"). |
| 28 x 1 1/2 | 635 | English, Danish, Chinese and Indian rod-brake road bikes (also designated F10, F25, 700 B). |
| 28 x 1 5/8 x 1 1/4 | 622 | Obsolete Canadian F.13 designation. |
| 28 x 1 5/8 x 1 1/4 | 622 | Northern European designation for 622 mm (700 C) tires. |
| 27 x [number] | 630 | Old road bikes. |
| 26 x 1 (650 C) | 571 | Triathlon, time trial, small road bikes. |
| 26 x 1 1/4 | 597 | Old British sports and club bikes. |
| 26 x 1 3/8 (S-6) | 597 | Schwinn light bicycles. |
| 26 x 1 3/8 (E.A.3) | 590 | Most 3-speed bikes, 10-speed kids bikes or supermarket bikes. |
| 26 x 1 1/2 (650B) | 584 | French touring or touring bikes, a few Raleigh (USA) and Schwinn mountain bikes. |
| 26 x 1 3/4 (S-7) | 571 | Schwinn Cruisers. |
| 24x1 | 520 | High quality wheels for small riders. |
| 24 x 1 1/8 | 520 or 540 | Buyer beware! |
| 24 x 1 1/4 | 547 | Children's bicycles Schwinn or British. |
| 24 x 1 3/8 (S-5) | 547 | Light children's bikes Schwinn. |
| 24 x 1 3/8 (E-5) | 540 | British children's bicycles, most wheelchairs. |
| 20 x 1 1/8 20 x 1 1/4 20 x 1 3/8 | 451 | Light children's bikes, BMX for light riders, some ligerades. |
| 20 x 1 3/4 | 419 | Schwinn children's bicycles. |
| 17 x 1 1/4 | 369 | Alex Moulton. |
| 16 x 1 3/8 | 349 | Old Moulton, Brompton and other folding bicycles, ligerade front wheels, children's bicycles. |
| 16 x 1 3/8 | 337 | Extremely mysterious tire size. |
| 16 x 1 3/8 | 335 | Polish children's bicycles. |
| 16 x 1 3/4 | 317 | Schwinn children's bicycles. |
| 12 1/2 x [number] | 203 | Children's bicycles, scooters |
| 10x2 | 152 | Wheelchairs. |
| 8 x 1 1/4 | 137 | Wheelchairs. |
It is also worth noting that initially fractional sizes were introduced for old rims with straight sidewalls. The more functional dimensions of 571mm / 26 x 1 and 630mm / 27 came later, on lug rims.
| 29" | 622 | Accepted name introduced by marketers. Applies to 622mm ("700c") tires. |
| 28 x [dec. number] | 622 | Some German tire manufacturers use this designation for tires with a bore diameter of 622 mm ("700c"). |
| 26 x 1.00 to 2.3 | 559 | Most mountain bikes, cruisers, etc. Except as follows: |
| 26 x 1.25 (obsolete) | 599 | Very old USA light bikes. |
| 26 x 1.375 | 599 | Very old USA light bikes. |
| 24x1.5-24x2.125 | 507 | Children's mountain bikes, cruisers. |
| 22 x 1.75; 22 x 2.125 | 457 | Children's bicycles. |
| 20x1.5-20x2.125 | 406 | Most BMX bikes, kids bikes, folding bikes, touring bikes and some ligerades. |
| 18 x 1.5 | 355 | Birdy folding bikes. |
| 18x1.75-18x2.125 | 355 | Children's bicycles. |
| 16x1.75-16x2.125 | 305 | Children's bicycles, folding, touring and some ligerades. |
Initially, in the French system, the first number indicated the outer diameter of the rim in millimeters, followed by the letter that determined the width: "A" - narrow, "D" - wide. The letter code is no longer associated with tire width, as narrow tires are often made to fit rims originally designed for wide tires. For example, the 700C size was originally a wide size, but now there are also very narrow 700C tires that have an actual diameter of only 660 mm.
| 700A | 642 | Obsolete size. |
| 700 B | 635 | Road bicycles with rod brakes. |
| 700 C | 622 | Road bikes, hybrids, 29" mountain bikes. (28 x 1 1/2 F.13 Canada) |
| 700D | 587 | Odd size previously used on some GT bikes. |
| 650A | 590 | French version 26 x 1 3/8; Italian high quality bikes for light riders. |
| 650 B | 584 | French pleasure bikes, tandems, touring bikes; some old Raleigh bikes and Schwinn mountain bikes. |
| 650 C | 571 | Triathlon, time trial, high quality road bikes for light riders. |
| 600A | 540 | European children's road bikes, most wheelchairs. |
| 550A | 490 | European children's road bikes. |
| 500A | 440 | European children's folding bikes. |
| 450A | 390 | European children's bicycles. |
| 400A | 340 | European children's bicycles. |
| 635 | 28 x 1 1/2, 700B |
| 630 | 27 x number |
| 622 | 700 C, 28 x (double shot), 29 in. (28 x 1 1/2 F.13 Canada) |
| 599 | 26 x 1.25 x 1.375 |
| 597 | 26 x 1 1/4, 26 x 1 3/8 (S-6) |
| 590 | 26 x 1 3/8 (E.A.3), 650 A |
| 587 | 700D |
| 584 | 650B, 26 x 1 1/2 |
| 571 | 26 x 1, 26 x 1 3/4, 650 C |
| 559 | 26x1. 00-x2.125 |
| 547 | 24 x 1 1/4, 24 x 1 3/8 (S-5) |
| 540 | 24 x 1 1/8, 24 x 1 3/8 (E.5), 600 A |
| 520 | 24x1, 24x1 1/8 |
| 507 | 24x1.5-x2.125 |
| 490 | 550A |
| 457 | 22 x 1.75; x 2.125 |
| 451 | 20 x 1 1/8; x 1 1/4; x 1 3/8 |
| 440 | 500A |
| 419 | 20 x 1 3/4 |
| 406 | 20x1.5-x2.125 |
| 390 | 450A |
| 369 | 17 x 1 1/4 |
| 355 | 18x1.5-x2.125 |
| 349 | 16 x 1 3/8 |
| 340 | 400A |
| 337 | 16 x 1 3/8 |
| 317 | 16 x 1 3/4 |
| 305 | 16x1.75-x2. 125 |
| 203 | 12 1/2 x number |
| 152 | 10x2 |
| 137 | 8 x 1 1/4 |
It is certainly possible to use almost any combination of tire and rim that has the same fit, but from a practical point of view it is unreasonable for the width of the tire to differ significantly from the width of the rim.
If the tire is too narrow for the rim, the risk of damage from various bumps and bumps increases significantly.
If the tire is too wide, the sidewalls of the tire are more likely to wear out quickly and the risk of losing control of the bike on a flat tire increases. Plus, handling at low speeds noticeably worsens.
Unfortunately, in order to save weight, modern mountain bikes use extremely narrow rims. These rims do not fit wide tires very well, unless they are pumped very hard. This, in turn, leads to unnecessary stress on the sidewalls of the rim, and also loses the main point of installing wide tires designed to work with low pressure.
GMS - Global Measuring System. Existing standards for measuring the size of an inflated tire do not take into account the difference in tread depth. To solve this problem and enable a more accurate comparison of tire performance, WTB introduced its measurement standard - GMS.
The standard consists of two numbers in millimeters: the first characterizes the width of the base of the tire; the second is the width of the outside of the tire, measured over the tread. Measurements are made on a rim with an internal width of 20 mm, and a tire inflated to 60 psi and after 24 hours of exposure.
In addition to the dimensions of the base and the outer width of the tread, the allowable tire pressure, the main characteristics of the tread and its contact area are indicated.
Single tube tires are most commonly used for cycling. Single tubes do not have sidewalls. During their production, the ends of a solid tire tube are connected to each other, forming a torus.
