Rims play a significant role in determining performance, aerodynamics, and overall ride quality. Here are a few key aspects to consider when it comes to road bike rims:
- Size: Road bike rims come in a variety of sizes, but the most common size for modern road bikes is 700c. The “700c” size refers to the approximate diameter of the rim, including the tire. This size has become the standard for road bikes and provides a good balance between speed, handling, and comfort. The diameter of a 700c rim is approximately 622 millimetres.
- Material:
- Aluminium: Aluminium rims are common and offer a good balance of strength, weight, and price. They are durable and provide reliable braking performance.
- Carbon fibre: Carbon fibre rims are lighter and more aerodynamic, making them a popular choice for performance road bikes. They can offer better aerodynamics and a smoother ride. However, they tend to be more expensive and may not be as durable as aluminium rims.
- Width: Wider rims can improve tire stability, comfort, and cornering grip. They also provide better support for wider tires, which are increasingly popular in road cycling. The standard width of road bike rims is usually 19 to 23 mm.
- Aerodynamics: Some rims are designed with specific aerodynamic features to reduce drag and increase speed. These features may include deeper rim profiles, aerodynamic shapes, and optimized spoke patterns.
- Tubeless compatibility: Many modern road rims are tubeless ready. Tubeless kits can reduce the risk of flats and provide a more comfortable ride at lower tire pressures.
Choosing road bike rims should be based on riding preferences and budget. It's important to find a balance between factors like weight, aerodynamics, durability, and price.
What is the usual number of spoke holes on road rims?
The recommended number of spokes for road bike rims can vary depending on factors such as rider weight, intended use, and rim construction. Road bike rims typically have a spoke count of 16 to 32, with 28 and 32 spokes being most commonly used.
Lightweight road bikes often use rims with a lower number of holes (16 to 20). These rims are usually paired with high-tension spokes to maintain stiffness and strength. For heavier riders or those planning to ride on rougher roads, rims with a higher number of spokes (24 to 32) are recommended, which provide more durability and support.
It is worth noting that advances in rim design and materials have allowed for stronger and stiffer rims, reducing the need for extremely high spoke counts. Additionally, some modern rims use asymmetrical spoke hole placement to improve the strength and stability of the wheel.
What materials are used to make road bike rims?
The following materials are commonly used for road bike rims:
- Aluminium: The most common choice for road bike rims. They offer a good balance between weight, affordability, and durability. Aluminium rims are lightweight and stiff, and provide excellent performance for most road bikes.
- Carbon fibre: Gained popularity in recent years due to their exceptional strength-to-weight ratio and vibration-damping properties. Carbon rims are significantly lighter than aluminium rims, which can improve acceleration and climbing. They also offer better aerodynamics and a smoother ride quality. However, carbon fibre rims tend to be more expensive than aluminium rims.
- Alloy: Some road bike rims are made from various alloys, which can contain a combination of metals such as aluminium, magnesium, or titanium. These alloys can offer different properties, such as higher strength or lower weight, depending on the specific composition.
Are there any specific rim profiles or shapes used in road cycling?
There are specific rim profiles or shapes that are commonly used and recommended for road bike rims. These profiles are designed to improve aerodynamics, stability, and optimize performance. Here are some common rim profiles:
- Box-shape: “Box-shape” rims have a traditional flat profile with a rectangular cross-section. They are often used on entry-level or training road bikes. Box-shape rims provide good strength and durability, but may not have the same aerodynamic benefits as other profiles.
- V-Shape: V-shaped rims, also known as semi-aero rims, have a slight V-shaped profile. They offer some aerodynamic benefits by reducing drag and improving stability in crosswinds. V-shaped rims are commonly used on mid-range road bikes.
- U-Shape: U-shaped rims, also known as deep-profile rims or aerodynamic rims, have a distinctive U-shaped profile. These rims provide significant aerodynamic benefits by reducing drag and improving air flow around the wheel. U-shaped rims are commonly used on high-end road bikes and are popular with time trialists and triathletes.
- Toroidal: Toroidal rims have a rounded, bulbous shape with a wider cross-section. They are designed to reduce drag and improve aerodynamics by creating a smoother transition of air from the tire to the rim. Toroidal rims are often used on high-performance road bikes.
