How To Choose The Size Of A Bicycle Tire

How to choose bicycle tires

Using unsuitable bicycle tires can significantly impair the performance of your bicycle. But a good choice of rubber can make the bike just “take off”.

The wheels of regular bicycles for adults come in diameters of 26, 27.5, 28 and 29 inches. Folding urban and some extreme models can be equipped with 20 or 24 inch wheels. The diameter is always written on the tires. For example, 26×2.1 means 26 inches in diameter and 2.1 inches thick. Note: 28 and 29 inch tires require the same 28 inch rim, but 26 and 27.5 require 26 and 27.5 inch rims, respectively. On road bikes, the wheel diameter is indicated as 700 or 70C. This is the same 28 inches, only in millimeters.

The thicker the tire, the better it softens bumps and adheres better to the surface, but also the greater its weight and the harder the bike rides on good asphalt due to the increased traction area. That is, for speed, tires are chosen narrower, and for cross-country ability or comfort. wider.

The tire width also depends on the bike frame. Road bikes are fitted with tires up to 32 mm thick, and mountain bikes up to 2.3 inches. The same tire model can be produced in different thicknesses. Unless you have a pure asphalt bike, don’t put the rubber right next to the frame. Leave a gap for mud on mountain and cyclocross or fenders on city bikes.

Standard bike tire types

Slick, or completely smooth rubber, is used for driving only on Smooth asphalt. Typical Representatives: Schwalbe Kojak, Rubena Cobra and Michelin Wild Run.

Semi-slick is a fairly versatile tire that allows you to ride on easy soil. Soft types of rubber, from which semi-slick are made, quickly grind on the asphalt. Typical Representatives: Continental Speed ​​King 2 Race and Schwalbe Sammy Slick.

The use of road rubber is asphalt. It is tougher and therefore wears out longer. Usually has some puncture protection. Typicals: Continental Town Ride, Schwalbe Land Cruiser and the most popular Schwalbe Marathon series.

Rubber with a developed tread (in common use. “evil rubber”) behaves well in mud, sand, snow, but on the asphalt they go very badly and, moreover, make a lot of noise. Typical representatives: Continental Mud King and Michelin Country AT. Compromise. Alignment of the tread teeth, forming a similar center track. Such tires are good both in mud and on asphalt. Typical Representatives: Schwalbe Smart Sam and Schwalbe Black Jack.

Balloon bike tires are tires that can function at low pressure, making them surprisingly comfortable. They are used for driving around the city or for tourism, since the tread of such tires does not have developed lugs. Typical Representative: Schwalbe Big Apple.

Special types of tires

Tubeless tires have anti-puncture properties. Commonly used in cycling because they require special rims or special seating bands and sealant. They are expensive, and in the event of a puncture, they are extremely difficult to glue and change. Studded tires are used for driving on ice. Regular rolled snow and Snow-covered urban asphalt do not require special tires, therefore studs are used only in races or in regions where ice is very frequent. A set of studded tires costs like a budget bike. A typical representative is the Schwalbe Ice Spiker. Solid tires are very poorly distributed in our market. They are difficult to place, but they DO NOT break through.

Often, the same tire model is available in two versions. regular, with steel cord (a mesh of steel wire or Kevlar threads that makes up the tire frame), or folding (folding) with Kevlar cord. Folding is more expensive and easier.

TPI (Threads Per Inch) is the density of the cords in tires. Less dense cords (from 30 to 60 TPI) allow to make tires softer and lighter, denser (90. 150 TPI) are used in more wear-resistant, hard tires.

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Compound is a term for the composition of rubber. Engineers can mix two or three different rubber grades into a single tire (dual and triple compound, respectively), allowing optimal cornering grip with good roll-off on the center track. Each manufacturer has its own formula and compound technology.

Weight is an extremely important characteristic of a tire, because the wheels are constantly spun by the cyclist, and the easier it is to do this, the less effort is spent on it. But the lighter the tires, the more expensive they are and, as a rule, the easier it is to break through. The higher the anti-puncture properties, the more difficult it is to puncture the tires. Tires of the highest grades are NOT punctured even with push pins. Simple tires can be punctured quite often in the conditions of Ukrainian littered roadsides. However, anti-puncture pays for weight. Good anti-puncture tires weigh 2 kg per set. Truly, these tires are needed only in some areas where thorns grow, and long-distance bike tourists.

Reflective elements are often used on modern rubber to increase visibility at night. Most often this is a side strip, but there is also an inscription itself. the name of the rubber. These tires are marked with the letters R, RT or Reflex.

Fatbike and cruiser bikes can have thicker tires. Wider tires are inflated with less pressure than narrow ones, which means that the wider the tire, the more comfortable and passable it is, but it rolls harder and worse on smooth asphalt.

How to choose gear ratios for bike wheel size

Having learned that when I switched to 1×9 I put a star of 34 teeth in front, one of my friends expressed doubt, they say, is it not enough. I shrugged it off, they say, I’m fine, and closed this question.
And then I thought about the fact that people who ask such questions do not always guess to take into account such factors as the size of the wheels, their weight, the type of tread, a comfortable cadence for me, and the weight of the bike itself. And if issues with weight and tread type are difficult to fit into simple and clear diagrams and equations to get visual results, wheel diameter and cadence. Quite clear concepts.
So today I want to talk about gear ratios and how they relate to cadence, wheel size and real speed.
As a hard-core humanist, I got to a lot by experience, without even going to delve into any calculations. But knowledge gaps need to be filled.
In the previous article, we examined the issues of moving to one star in front and found out the gear ratio by dividing the number of teeth of the leading star by the number of teeth driven. What does this number mean??

The number obtained as a result of dividing is, in fact, the number of revolutions of the rear wheel that it will make in a given gear in one revolution of the system.
So, for example, with a ratio of 40/10, the wheel will return 4 times in one circle of the system, 40/40.Once 40/50. 0.8 times, and so on.
Having this information, let’s try to tie it to the diameter of the wheels.
To find out how far your wheel travels in one revolution, recall the formula for the circumference. C = Πd (circumference = 3.14circle diameter). For a conventional wheel of 26 inches, it will be 3.1426 = 81.64 inches. Which is equal to 81.6425.4 = 2073.656 mm = 207.3656 cm = 2.073656 m.Since the measurement of wheel dimensions in inches is rather arbitrary, for greater accuracy we will take information on the circumference of wheels with different tires in one of the many tables for bike computers. But the circumference of your tire is easy to measure on your own, just a wheel and a tape measure, roll it on the floor and measure from nipple to nipple, for example.

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One stars, one cadence. Different diameters.
To begin with, let’s take a conditional cyclist for our calculations, who rides with a comfortable cadence of 80 rpm, with a 34×11-40 transmission on bicycles with different wheel sizes.
In order not to overload you with numbers, let’s take the maximum / minimum, that is, the ratios 34/40 = 0.85 and 34/11 = 3.09

Tire sizewheel speedspeed
29×2.2 inches (2298mm)3.09×2.298 = 7.1 m80×7.1mx60min = 34080m / h = 34 km / h
0.85×2.298 = 1.9 m80×1.9mx60min = 9120m / h = 9.12km / h
26×2.1 inches (2068mm)3.09×2.068 = 6.39 m80×6.39mx60min = 30528m / h = 30.5km / h
0.85×2.068 = 1.75 m80×1.75mx60min = 6960m / h = 6.9km / h
24×2.0 inches (1925mm)3.09×1.925 = 5.95 m80×5.95mx60min = 28552m / h = 28.5km / h
0.85×1.925 = 1.64 m80×1.64mx60min = 7854m / h = 7.8km / h
20×1.95 inches (1565mm)3.09×1.565 = 4.84 m80×4.84mx60min = 23232m / h = 23.2km / h
0.85×1.565 = 1.33m80×1.33mx60min = 6384m / h = 6.4km / h

As we can see from the table, for the same cadence and the same transmission, the speed of cyclists varies significantly depending on the size of their wheels. And if the 34th star in front is quite Reasonable for large wheels (I have 27.5×2.8, which is essentially the same 29 in circumference), then for folding bicycles with 20-inch wheels it is clearly not enough.

Different cadence, different stars, same diameter.
But the cadence can also be changed! Beginner cyclists ride with a cadence of about 60 revolutions per minute, while the cadence of athletes exceeds one and a half hundred! Comfortable values ​​for most vary from 70 to 120, but this greatly depends on the level of training. I have noticed from myself that over the years my cadence has become noticeably higher, and instead of power pedaling in high gears, I increasingly choose to ride lower ones with high cadence. It Reduces stress on the knees, but requires some training.

Let us consider the change in speed depending on the cadence using the example of a single speed bike, which you might want to assemble yourself, but do not know which stars to choose in order to ride it comfortably in a flat garden like St. Petersburg.

So, you have a trendy single / fix, light and fast, on narrow rubber 700×25 (2105mm circumference), a sprocket with 18 teeth in the back, and you want to screw 40km / h on it, but you are also curious how comfortable a slower ride will be.
Let’s go from the opposite! I, as already mentioned, a humanitarian, so we will consider it in stages.
First, let’s find out the distance that needs to be covered in one revolution of the wheel with a fixed cadence.
40km / h = 40000m / h, with a cadence of 120rpm we get
40000m / h: (120rpm x 60 minutes) = 5.55 meters the wheel will travel in one revolution.
Knowing its circumference, we get the gear ratio
5.55: 2.105m = 2.64.

Recall that we have 18 teeth in the back sprocket, let’s calculate how much the front sprocket should be to get the desired result.
18×2.64 = 47.5 teeth. That is, the 48 tooth star.

Okay, how fast can we roll on it, having reduced the cadence to 70 rpm? 48/18 = 2.66
2.66×2.105x70x60 = 23576m / h = 23.6 km / h
If these values ​​suit you, then a 48th star with these wheels and an 18 star in the back is optimal for you.

I hope this article helps you understand the vast world of bicycle wheels and drivetrains.

Tire fitting recommendations

Get some paddles. this will facilitate the installation process (these tools will also be useful in your arsenal of cycling things). After mounting, inflate the wheel to 1 atmosphere, then align the tires on the rim. DO NOT do this. there is a high probability that the tire will sit unevenly and will be “eight”.

After. pump up to 2 atmospheres and leave it for a day. After that, add the pressure you need.

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The hero of the following tells more about how to properly pump up a bicycle camera:

Tire size

Bicycle tires are always marked on the sidewall with a minimum of 2 parameters. These dimensions usually indicate:

  • Or in inches (for example 29 x 2.10)
  • Either in millimeters (622 x 52).

The first value in our example indicates the diameter of the tire (usually the rim diameter), the second indicates the width-height of the profile. The higher the second value, the wider your chosen tire will be.

The easiest way to choose tires for a bicycle is to look at the parameters on the old one, and choose a new one in accordance with them. But you can also vary, but only the width. For example, instead of 1.5 “tires, he will put 2.2” rubber. It’s real. The main thing is the correspondence of the bore diameter to the rim.

Tip: When buying wider bicycle tires, pay attention to the brakes. If you have rims, the tire may NOT fit in there. Tires that are too wide sometimes DO NOT even fit into the fork. The other side of the coin is tires that are too narrow. Such on bicycles (for example, mountain bicycles), with Incorrect installation on turns, can rally.

Vary the width of the tire over a small range. And always buy them according to the diameter.

When buying a bicycle tire, pay attention to its diameter and width

When size matters: how to choose bicycle tires

There are many types and manufacturers of bicycle tires today. How to choose them?

How To Choose The Size Of A Bicycle Tire

Budget

Why are some tires more expensive than others? What is the reason? The price is formed not only by the brand-manufacturer, but also by the following factors:

  • The weight. The lighter and more technologically advanced a tire, the more expensive it is. The most expensive tires are professional models for competitions with the minimum weight and the maximum number of technological solutions.
  • The size. The larger the tire, the more material and time it takes to manufacture it. And accordingly, the cost increases.
  • Cord type. (The rim inside the tire, giving it rigidity). There are 2 types of cord. steel and Kevlar. Steel. heavy, non-compact, cannot be crushed (crushing can damage the structure). Kevlar. lightweight, compact, 20-30% more expensive.

Bicycle tires with Kevlar cord are more expensive but lighter

The type of surface you ride

Bike tires should be selected to match the surface you ride on. Love to ride over rough terrain, soil? Your option is tires with protectors (spikes). The more aggressive the conditions in which you will ride, the more difficult the pattern on the tires should be, the larger the stud diameter. This combination will better cling to the ground and prevent the bike from slipping.

Do you like speed? Driving on the highway? The ideal option is tires without protectors and patterns at all, since they will “eat up” your speed, as well as strength and energy. Usually these are lightweight, which has a positive effect on high-speed driving.

There are winter bicycle tires. Their main distinguishing feature is the presence of an aluminum core in the studs. again, for improved traction with the soil, ice in particular.

The main distinguishing feature of winter bicycle tires is the presence of an aluminum core in the studs

Storage

DO NOT store your bike with flat wheels. the tire will quickly deteriorate. DO NOT store your bike in direct sunlight. the tire may dry out and begin to crack. Ideal: Store in a medium humidity room at room temperature and pressure in 1 atmosphere chambers.

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