Basic Knowledge of Rim Selection

Rim Diameter

Each bicycle has a specific size, which usually cannot be changed.
Check the tire or rim for numbers such as 26", 27.5", 29", 650b, 650c, 700C, etc.

Rim type

There are rims for rim brakes, disc brakes, etc. Be aware that some rims are specially designed for rim brakes and cannot be used with other types of rims.

Rim Specifications

There are two main types of rim specifications: tubed and non-tubed.

Tubed (called clincher or WO): The most common specification, using a tube to inflate the tire, has the most rim options and can be selected according to the application.

Tubular (requires specialized tires): Specification that requires specialized rims and tires; overwhelmingly comfortable to ride, but incredibly difficult to repair a flat tire. It is impossible to repair a puncture on the road.

Tubeless: Special tires and valve cores are used to inflate the tire without the use of a tube. This method has many advantages, such as preventing punctures on the rim, improving tire performance, and reducing weight, but it is difficult to handle.

Tubeless Ready: A simpler version of the tubeless specification that uses a special tire, rim, valve core, rim tape, and sealant fluid to achieve the same performance as tubeless tires.

Rim height (vertical rim height): greatly affects aerodynamic drag.

Higher height reduces aerodynamic drag in the direction of rotation, while lower height increases it.
However, higher height increases weight on non-carbon rims, so balance is important.
In general, the lighter the outer circumference of a wheel, the lighter it is to step on.

Rim width (horizontal rim width. Note that there is an outer width and an inner width)

It affects the shock absorption capacity and the width of the tire. The width of the rim also determines the use of the tire. Simply put, a wider rim is for mountain biking and a narrower rim is for road riding.

The width of the outside of the rim affects the shock absorption capacity, and the thicker the tire, the higher the absorption capacity, but depending on the frame, it may not be possible to mount the tire. It is essential to check the clearance.

The width of the inside of the rim greatly affects the width of tires that can be mounted. A narrow tire cannot be mounted on a wide rim, and vice versa. Please refer to the general compatibility chart available.

Number of holes in the rim: Number of holes on the inside diameter side of the rim for the spokes and nipples to pass through.

The number of holes must be the same as the number of holes in the hub.
If the number of holes is reduced and the number of spokes is decreased, aerodynamic drag is reduced, but the force against torsion is weakened.
This also has a significant effect on the life of the wheel. The more holes, the longer the wheel will last, but the heavier it will be and the more aerodynamic resistance it will have.
In general, the following is often the case

• Road: 20 to 32 holes
• Cross: 28-32 holes
• MTB : 28-36 holes
• Touring & Cargo Bike Motorcycle & Utility Vehicle : 32-36 holes

Basic Knowledge of Hub Selection

Located at the center of the wheel, this component is responsible for the wheel's rotational force. There is a wide range of types and prices.

Specifications of hubs

There are cantilever, caliper brake, and disc brake types, so it is important to match the type of brake with the type of bicycle to which the hub will be installed.

Gear shift specifications

There are fixed gear (track bikes), single speed, multi-speed (7~10, 11, 12 speed), and component makers (Shimano & Sram, Campagnolo, etc.), etc. Check the manufacturer and number of gears you are using.

End width

Width of the part where the wheel is attached. Also called overlock nut dimension (OLD).
100mm is common for the front. Recently, 110mm and other boost standards are increasing.
Rear widths are 110mm, 120mm, 130mm, 135mm, 142mm, 148mm, etc. There are many different widths, so be sure to check the size of your frame.

How to fix to the frame

Quick release type, nut fastening, through-axle, etc., are available depending on the frame.

Number of holes in the hub

The number of holes on the flanges on both sides of the hub for the spokes to pass through.
The number of holes must be the same as the number of holes in the hub.
If the number of holes is reduced and the number of spokes is decreased, aerodynamic drag is reduced, but the force against torsion is weakened.
This also has a significant effect on the life of the wheel. The more holes, the longer the wheel will last, but the heavier it will be and the more aerodynamic resistance it will have.
In general, the following is often the case

• Road: 20 to 32 holes
• Cross: 28-32 holes
• MTB : 28-36 holes
• Touring & Cargo Bike Motorcycle & Utility Vehicle : 32-36 holes

How to choose spokes

The component that connects the hub to the nipple. Affects aerodynamic drag and the strength of the entire wheel against torsion.

Plain spoke

Spokes with a circular cross-sectional view, the most common shape.

Size

#14: The most common spoke thickness for sports cars with an outer diameter of 2.0 mm. Used on various types of bikes from road to cargo bikes.

#15: Spokes with an outer diameter of 1.8 mm. The thinner and lighter spokes emphasize the weak point of the spoke, called the neck, so they are not suitable for hard use.
It is used for bicycles that require lightness.

#14-15-14: Double-butted spokes. The tip and back end are thicker and the center is thinner. This spoke is used to add strength to the weak point of a thin spoke while also making it lighter in weight.
#13-14: The weak point of the spoke, known as the neck, is thicker to provide strength and durability.

Aero Spoke

The spoke cross section is like a plate, and the area of the spoke in the direction of rotation is smaller, which is expected to reduce aerodynamic drag. However, in the lateral direction, it is affected by crosswinds due to its plate-like shape.
The torsion resistance is also weaker than that of plain spokes.

How to choose a nipple

The part that connects the spokes to the rim.

Material

Brass: heavier but stronger nipple with a longer life.
Aluminum: Light in weight, but wears out faster than Brass, and needs to be replaced every few years.

Size

The size of the spoke should be determined according to the size of the spoke.