Choose the right tire size for your road bike
introduction
In the past, the typical width of most road tires was 23mm, with some even being 20mm wide or narrower. In recent years, racing bikes have increasingly used wider tires. Today, the narrowest tire commonly fitted to road bikes is 25mm, and many bikes are fitted with 28mm tires. There is room for 32mm rubber and even wider tires on some of the latest models. Wider tires can provide better grip, more comfort and lower rolling resistance.
This guide will help you determine the tire width that suits your riding style and the conditions in which you ride.
bicycle tire size systems
Throughout history, different countries have used their own methods of labeling bicycle sizes, resulting in different numbers for identifying equal tire sizes. As cycling becomes increasingly popular around the world, a standardized approach was needed to make the job easier for everyone.
Traditional tire sizing systems are based on the outside diameter of an inflated tire, measured in inches or millimeters. However, the ISO standard designation for tire sizing uses the diameter of the wheel bead seat in millimeters, followed by the width of the inflated tire in millimeters.
Tire sizes in inches are identified by specifying the width as a decimal (e.g. 26 x 1.75) or fractional (e.g. 26 x 1 3/4). Although two size designations may appear mathematically the same, they may refer to different tire sizes that are not interchangeable. For example, 28 x 1 1/2 is not the same size as 28 x 1.50.
Credit from: biketiresize
The tire size is located on the sidewall of the tire and is indicated by two numbers that generally correspond to the outside or inside diameter and the tire width. These numbers may seem confusing at first, but they are actually quite simple. Additionally, a tire can have one, two, or even three sets of size numbers. If any of these number groups on a new tire match the markings on your old tire, the new tire should fit your rim.
Common road bike tire sizes
Here you will find an overview of common racing bike tire sizes.
| ETHRO | Dimensions |
|---|---|
| 18–622 | 700×18c |
| 23–622 | 700×23c |
| 25–622 | 700×25c |
| 28–622 | 700×28c |
| 30-622 | 700×30c |
| 32–622 | 700×32c |
How to choose
aerodynamics
There is a general concern that wider tires may be less aerodynamically efficient than narrower ones. However, various studies have shown that a combination of slightly wider tires and wider rims can actually improve aerodynamic performance. This is because wider tires and rims create a smoother transition between tire and rim, resulting in less turbulence and drag. Recent studies have shown that wider tires, such as 28mm or even 30mm, can be faster than narrow ones. This is because wider tires create a larger contact area with the road, resulting in lower rolling resistance and a smoother ride. In addition, wider tires can be run at lower pressures, which can further reduce rolling resistance and increase comfort.
Credit from: Cyclist
Comfort
Wider tires offer several benefits, including greater comfort. These tires can be run at lower pressures, allowing them to absorb more shock and vibration from the road. As a result, they provide a smoother and more comfortable ride, especially on bumpy or uneven roads. Additionally, wider tires provide better traction and stability, resulting in more confidence and control when driving.
Credit from: Cyclist
terrain suitability
If you plan to ride on smooth roads, it's best to use 25c tires as they reduce rolling friction during races or interval sessions. For most paved terrain, 28c-30c tires are a good choice. However, if you ride on rough roads or are a heavy rider, a 30c or 32c tire may be a better option.
Credit from: Cyclist
frame spacing
Always check that brakes, chainstays and forks have enough space before adjusting the size. Most road frames easily accommodate 25c-28c tires. With wider 30c tires it may be necessary to switch to wider inner rim widths on some frames. The 32c size pushes the limits of scope on all but endurance-focused designs. Typically, bicycle manufacturers specify the maximum tire width and a safe clearance range between the tire and frame for each model in their range. This information can usually be found on the manufacturer's website.