The efficiency of bicycle wheels largely depends on the quality of their components. A wheel consists of three main elements: the hub, the rim, and the spokes. Spokes play a crucial role in connecting all parts together. In this article, we’ll explore various aspects of bicycle spokes and how to choose the optimal option for your bicycle.

Functions and Features of Spokes

Spokes in a bicycle wheel serve an important function by connecting the hub to the rim. Thanks to spokes, the wheel achieves high strength while maintaining a light weight. In addition to providing structural integrity, spokes also act as shock absorbers. Their flexibility allows for even distribution of load across the entire rim. Positioned vertically, spokes counteract the force of gravity.

Design Features

Spokes are attached to the hub flanges and the rim, usually at a specific angle, as the nipple holes are located in the center of the wheel rim. The design of spokes differs at both ends. On one end, the nipple is tightened using a special wrench, while on the other end, the spoke is simply inserted into the hub flange, where it is held in place by a pressed head.

Types and Materials of Spokes

Despite their apparent simplicity, there are many varieties of spokes. They differ in the following parameters:

1. Sizes: The length of spokes depends on the wheel size and spoke pattern.
2. Materials: Modern alloys are used for both coating and the main structure of spokes.
3. Attachment methods: Although the standard has mostly settled, there are still various options.

Types by Size

Not all spokes have a round cross-section. There are several types of cross-sections:

• Single and double butted: Thickenings are made at the ends of round wire. With single butting, the thickening is on the head side.
• Triple butted: “Composite” models where the cross-section diameter changes in one direction in two steps. Usually, the thickening is shifted towards the wheel center.
• Aerodynamic: Elliptical and flat variants for speed racing, sometimes teardrop shapes are encountered.

The width of spokes is measured in AWG (American Wire Gauge). The most common sizes are 12g and 14g, corresponding to 2.6797 mm and 2.032 mm respectively. The length of spokes is not standardized as it’s produced in a wide range.

Types by Materials

Most spokes are made of steel – these are strong, reliable, and inexpensive products. However, other materials are also used:

• Titanium: A stronger and more reliable metal, but significantly more expensive. Cast titanium spokes are used in trial and downhill to withstand enormous impact loads.
• Carbon fiber: A very light and sufficiently strong material, but even more expensive. It’s mainly used in racing bicycles due to its low weight and good aerodynamic properties.

Attachment Points and Methods, Innovations

Currently, the standard is a J-shaped head, which is threaded through a hole in the hub flange. Recently, wheels with straight spokes, without bends, have appeared, but these are only sports models so far.

Spokeless wheels are also being developed. Their role is beginning to be fulfilled by carbon fiber inserts, and some manufacturers are moving to cast wheels, manufactured similarly to car rims. Although this design is very reliable, it’s still too heavy and not without drawbacks. Additionally, there’s a problem with crosswinds, which can become a real safety threat. Protection against vibrations and accidents in such variants is rather negative. Replacement of non-standard models is also problematic due to small batches and the difficulty of finding unique parts, especially in small towns.

Spoke Pattern

The spoke pattern, or “lacing,” determines the number of spokes in the wheel, the rule of their arrangement, and the order of attachment to the hub and rim. There are several standard patterns. The process of installing spokes is called “lacing” and requires great attention to detail.

Patterns are usually classified by the number of “crosses,” i.e., intersections of a spoke with others attached to the same flange. The de facto standard is “three cross” – this is convenient for tensioning and repair. The extreme variant is considered “four cross,” where the spoke is turned almost 90 degrees from the conditional radius. The opposite variant is radial arrangement, where spokes do not intersect at all.

Each variant has its advantages. A large angle increases the length of spokes, which improves shock absorption, less dampens pedaling energy, and provides a large safety margin. The radial variant is very light due to the minimal length of spokes, but less reliable and more difficult to maintain.

Lacing Process

Wheel assembly, or lacing, is a complex process that requires attention and precision. Here are the main stages:

1. Preparation of materials: spokes of the required quantity and size, a hub with suitable flanges, a rim with corresponding nipple slots, a spoke wrench.
2. Lubrication and inspection of spokes.
3. Insertion of spokes into the wheel, starting with the key spoke, without over-tightening.
4. Gradual and even tightening of all spokes.
5. Checking and eliminating “wobble” – aligning the rim by tensioning spokes from different sides.
6. Checking and correcting the ellipse – adjusting spoke tension to eliminate bulges and dips.
7. Checking the “dish” – aligning the center of the rim profile relative to the bicycle center.
8. Final tensioning and checking the seating of nipples.
9. Removing lubricant and filing down protruding spoke ends.

It’s important to note that wheel assembly is complex work, especially for a novice. It should only be undertaken in a good mood and state to avoid mistakes. If even one spoke breaks, it’s a reason to redo the entire work.

Choosing Spokes

When choosing spokes, several factors should be considered:

1. Length: It’s necessary to accurately calculate the length of spokes depending on the sizes of the hub, rim, and type of attachment. It’s better to use special calculators for calculation.
2. Material: For most applications, steel spokes are sufficient, possibly with a small protective coating. Steel is easily straightened, repaired, and installed.
3. Geometry: For ordinary use, the simplest geometry will suffice. With increased loads or for trick bicycles, thickened variants should be considered.
4. Quantity: The standard for a mountain bike is 28-32 spokes. A smaller number increases the load on each spoke, while a larger number unnecessarily weighs down the wheel.
5. Tools: In advance, acquire a quality spoke wrench.

It’s important to remember that installing spokes is a difficult task for a novice, and it might be better to entrust this work to professionals.

Reasons for Spoke Breakage

Spokes can break for various reasons:

1. Low quality: Cheap spokes from unknown manufacturers often break due to poor-quality metal or manufacturing defects.
2. Incorrect length: Too short spokes create excessive tension and can snap.
3. Mechanical damage: For example, the chain can get caught between the cassette and spokes, damaging them.
4. Excessive tension: Over-tightened spokes cannot withstand loads and break over time.
5. Metal fatigue: Over time, even quality spokes can fatigue and break.

When a broken spoke is discovered, it’s important to determine the cause of the breakage. Sometimes it’s enough to simply replace one or two spokes, in other cases, replacement of the entire set or even choosing spokes from another manufacturer may be required.

Conclusion

Spokes are a small but critically important element of bicycle construction. Not only the pleasure of riding but also the cyclist’s safety depends on their quality and correct installation. When choosing spokes, it’s important to consider many factors: from length and material to the lacing configuration and quality of tension. Even if you’re just replacing spokes, this process should be approached with all seriousness. Properly selected and installed spokes will ensure reliability, comfort, and longevity of your bicycle wheel.