The Impact of Bicycle Wheel Design on Performance, Stability, and Durability

Introduction: The Bicycle Wheel – A Critical Component in Cycling Performance

The bicycle wheel, seemingly a simple circular component, stands as a cornerstone of cycling performance, profoundly influencing the rider’s experience and the bicycle’s overall capabilities. Its design, encompassing a complex interplay of materials, geometry, and construction techniques, dictates a multitude of characteristics that directly impact speed, handling, comfort, and longevity. Understanding the nuanced effects of these design choices is paramount for cyclists seeking to optimize their equipment, engineers striving to innovate, and manufacturers aiming to deliver superior products. This report delves into the scientific and engineering literature to provide a comprehensive review of how various aspects of bicycle wheel design affect performance, stability, and durability. By focusing on evidence-based research and independent evaluations, this analysis aims to offer an unbiased perspective, moving beyond marketing rhetoric to explore the fundamental principles that govern this critical component.

Aerodynamic Drag and Rolling Resistance: The Influence of Rim Design

The bicycle rim forms the outer structure of the wheel and plays a crucial role in both aerodynamic efficiency and rolling resistance, two key factors that directly impact a cyclist’s speed and effort. The material, depth, width, and overall shape of the rim are all critical design parameters that influence these performance characteristics.

Rim Material and Aerodynamic Implications

The selection of rim material significantly impacts the aerodynamic potential of a bicycle wheel. Predominantly, rims are constructed from either aluminum alloys or carbon fiber composites. Carbon fiber’s advanced manufacturing processes allow for the creation of more intricate and aerodynamically optimized rim profiles compared to aluminum. This is because carbon fiber can be molded into complex shapes with greater precision than aluminum alloys, which are typically extruded and then formed. This inherent advantage in shaping enables engineers to design rims with features like deeper sections and toroidal (donut-like) shapes, which are known to improve airflow management and reduce aerodynamic drag – a significant resistive force at higher cycling speeds. While aluminum offers a favorable balance of weight and strength, its manufacturing limitations constrain the complexity of aerodynamic profiles that can be economically produced. Consequently, high-performance wheels prioritizing aerodynamic efficiency often utilize carbon fiber rims to achieve shapes that minimize air resistance by promoting laminar flow and reducing turbulence around the wheel.

The Role of Rim Depth in Aerodynamic Drag and Side Force

Research consistently demonstrates a strong correlation between rim depth and aerodynamic drag reduction. Studies have shown that deeper rims, typically ranging from 60 to 90 millimeters, can yield substantial reductions in drag compared to traditional, shallower rims. One study indicated that wheels with rim depths in this range exhibited drag values as much as 60% lower than a standard non-aerodynamic wheel. This reduction in drag translates directly to lower power requirements for the cyclist to maintain a given speed. However, this aerodynamic advantage comes with a notable trade-off: an increase in side force. Deeper rims present a larger surface area to the wind, and while this is beneficial in headwind conditions or at low yaw angles (the angle between the direction of travel and the apparent wind), it also makes the wheel more susceptible to lateral forces generated by crosswinds. These increased side forces can negatively impact the bike’s handling and stability, potentially requiring more rider input to maintain a straight line, especially in gusty conditions. Therefore, the decision regarding optimal rim depth involves a careful consideration of the typical riding environment and the rider’s ability to manage the increased side forces associated with deeper rims. In regions with frequent and strong crosswinds, cyclists might opt for shallower rims to prioritize stability and control, even if it means accepting a slight compromise in pure aerodynamic efficiency.

Rim Width and Shape Optimization for Aerodynamic Efficiency

Beyond depth, the width and overall shape of the bicycle rim are critical determinants of aerodynamic performance. Academic research highlights the significant dependency of aerodynamic drag on the combination of the wheel and tire, with a strong linear correlation observed between wind-averaged drag and the ratio of tire width to rim width. This underscores that the wheel’s aerodynamic efficiency is not an isolated property of the rim but rather emerges from the integrated system of rim and tire. Modern aerodynamic rim designs often aim to optimize the airflow transition between the tire and the rim, striving for a smooth contour that minimizes turbulence as air flows around the rotating wheel. Computational Fluid Dynamics (CFD) analysis and wind tunnel testing have become indispensable tools in this optimization process, allowing engineers to evaluate and refine rim shapes across a range of yaw angles. These methods enable the identification of rim profiles that exhibit low drag not just in a direct headwind but also at the small to moderate yaw angles that are commonly encountered in real-world riding conditions. A key principle emerging from this research is the importance of the tire width relative to the rim’s external width. An optimal aerodynamic setup often involves a tire that is slightly wider than the rim, following what is sometimes referred to as the “105% rule”. This configuration helps to smooth the airflow and prevent the tire from being aerodynamically “slower” than the rim. However, the ideal width relationship can be complex and may vary depending on the specific rim shape and tire characteristics.

Rim Design and its Influence on Rolling Resistance

While the primary focus of rim design is often on aerodynamics, the width of the rim also plays a crucial role in optimizing the performance of the tire, which is the primary factor determining rolling resistance. Wider rims provide better support for wider tires, influencing the tire’s profile and the pressure at which it can be effectively run. This is significant because wider tires, when run at appropriate lower pressures, can exhibit lower rolling resistance on rougher surfaces compared to narrower tires at higher pressures. The wider contact patch of a wider tire at lower pressure can conform better to uneven terrain, reducing energy losses due to hysteresis – the internal friction within the tire as it deforms and recovers. Additionally, the shape of the tire’s contact patch, which is influenced by the internal width of the rim, can affect rolling efficiency. Some theories suggest that a wider, shorter contact patch, often facilitated by a wider rim, can lead to less deformation during rotation and thus lower rolling resistance. Therefore, while rim design is critical for aerodynamic performance, its width has a substantial indirect impact on rolling resistance by influencing the tire’s behavior and the cyclist’s ability to optimize tire pressure for different riding conditions. Modern trends in cycling favor wider rims (with internal widths typically ranging from 19 to 21 millimeters) paired with wider tires (25 to 28 millimeters for road bikes, and even wider for gravel and mountain bikes) to strike a balance between aerodynamics, comfort, and potentially lower rolling resistance, especially on less-than-perfect road surfaces.

Stiffness, Handling, and Power Transfer: The Role of Spokes

The spokes of a bicycle wheel connect the central hub to the outer rim, providing crucial structural support and playing a significant role in the wheel’s stiffness, which in turn affects handling and the efficiency of power transfer from the rider to the road. Stiffness in a bicycle wheel can be broadly categorized into lateral stiffness (resistance to sideways deflection) and vertical stiffness (compliance, or the ability to absorb vertical impacts).

Lateral and Vertical Stiffness: Definitions and Significance

Lateral stiffness refers to a bicycle wheel’s resistance to flexing sideways when subjected to lateral loads, such as those experienced during cornering or sprinting. High lateral stiffness is generally desirable as it contributes to more precise handling, allowing the rider to maintain their line through corners with greater confidence, and it minimizes unwanted flexing that can lead to brake rub or a feeling of vagueness in steering. Additionally, it is believed to enhance power transfer by reducing energy loss through wheel deformation during hard pedaling efforts. Vertical stiffness, often referred to as compliance, describes the wheel’s ability to absorb vertical impacts and vibrations from the road surface. A certain degree of vertical compliance is important for ride comfort, as it helps to dampen vibrations transmitted to the rider, reducing fatigue, especially on longer rides or rougher terrain. Furthermore, vertical compliance can contribute to better traction by allowing the wheel to maintain contact with uneven road surfaces. Achieving an optimal balance between lateral stiffness for performance and vertical compliance for comfort and control is a fundamental consideration in bicycle wheel design.

Influence of Spoke Count on Stiffness and Compliance

The number of spokes in a bicycle wheel is a significant factor influencing its overall stiffness. Generally, a higher spoke count tends to result in a stiffer wheel, both laterally and radially (vertically). This is because more spokes distribute the load more evenly across the rim and hub, increasing the wheel’s resistance to deformation under various forces. However, increasing the spoke count also adds to the overall weight of the wheel and can potentially have a slight negative impact on aerodynamic drag due to increased air turbulence. Consequently, there is often a trade-off between spoke count and wheel weight/aerodynamics, particularly in performance-oriented wheels where minimizing weight and drag is crucial. Lightweight and aerodynamic wheelsets often feature lower spoke counts, typically ranging from 16 to 20 spokes, to achieve these performance benefits. However, this reduction in spoke count can potentially compromise the wheel’s strength and stability, especially for heavier riders or those who subject their wheels to more demanding riding conditions. Therefore, the optimal spoke count for a bicycle wheel is a compromise that depends on the intended use of the wheel, the rider’s weight and power output, and the desired balance between performance, durability, and weight. While a higher spoke count generally increases the overall stiffness of the wheel, its effect on vertical compliance, or ride comfort, is often minimal compared to other factors such as tire pressure and the construction of the tire casing. The tire acts as the primary suspension element of the wheel, and the relatively small changes in spoke count within a typical range have a much smaller impact on the wheel’s ability to absorb vertical shocks compared to the compressibility of the tire.

Impact of Spoke Material on Wheel Stiffness and Strength

The material from which bicycle spokes are made has a secondary effect on the overall stiffness of the wheel compared to the spoke’s cross-sectional area, or gauge. For common spoke materials like steel, the stiffness is primarily determined by how much material is present (the thickness of the spoke). However, the choice of spoke material can significantly influence the wheel’s overall weight and its long-term durability, particularly its resistance to fatigue. Carbon fiber spokes represent a more recent development in wheel technology, offering the potential for significant weight reduction compared to steel spokes. Additionally, some manufacturers claim that carbon fiber spokes can offer comparable or even superior stiffness to steel at a lower weight. Furthermore, carbon fiber may exhibit better fatigue resistance than traditional steel spokes, potentially leading to a longer lifespan for the wheel. However, carbon fiber spokes typically come at a higher cost than steel and may have different failure characteristics under extreme stress or impact. While a steel spoke might bend, a carbon fiber spoke is more likely to break. Therefore, the decision to use carbon fiber spokes involves weighing the performance benefits of reduced weight and potentially increased stiffness and fatigue life against the higher cost and different durability profile compared to steel.

Spoke Lacing Patterns and their Effects

The pattern in which spokes are laced from the hub to the rim is a crucial design element that allows engineers to fine-tune the stiffness characteristics of a bicycle wheel for its intended purpose. Different lacing patterns, such as radial (0-cross), 2-cross, 3-cross, and more, affect the wheel’s lateral, vertical, and torsional stiffness. Torsional stiffness, which is the wheel’s resistance to twisting forces applied at the hub (such as during pedaling or braking), is particularly influenced by the lacing pattern. Patterns with more spoke crossings generally exhibit higher torsional stiffness, which is important for efficient power transfer from the pedals to the rear wheel. For lateral stiffness, 2-cross lacing is often recommended as providing the best balance. Radial lacing, where spokes run directly from the hub to the rim without crossing, is lightweight and can offer high lateral stiffness, particularly in front wheels where torque transfer is less critical. However, radial lacing is generally not ideal for the rear wheel drive side as it is less effective at transmitting the torque generated during pedaling. In such cases, crossed patterns, where spokes intersect each other, are preferred as the more tangential orientation of the spokes relative to the hub provides a longer lever arm for transferring rotational force. The choice of lacing pattern, therefore, involves a trade-off between different types of stiffness and the wheel’s intended use. Rear wheels often utilize crossed patterns on the drive side for efficient torque transfer, while front wheels might employ radial lacing for weight savings and enhanced lateral stiffness. It’s worth noting that the actual difference in lateral stiffness between commonly used crossed patterns (e.g., 2-cross vs. 3-cross) might be marginal compared to the influence of other factors such as rim stiffness and spoke gauge.

Wheel Weight: Its Impact on Acceleration, Climbing, and Ride Feel

The weight of a bicycle wheel significantly influences several aspects of its performance, most notably acceleration, climbing ability, and the overall feel of the ride. Reducing wheel weight is often a primary goal in high-performance cycling as it can lead to noticeable improvements in these areas.

Rotational Inertia and Acceleration Performance

A fundamental principle of physics dictates that objects with lower mass require less force to accelerate. This principle applies to bicycle wheels, where the concept of rotational inertia comes into play. Rotational inertia is a measure of an object’s resistance to changes in its rotational speed. Lighter wheels have lower rotational inertia, meaning they require less energy to spin up to speed. Conversely, heavier wheels have higher rotational inertia, making them more resistant to acceleration. Notably, the distribution of weight within the wheel also matters. Weight located further from the axis of rotation (i.e., at the rim) has a greater impact on rotational inertia than weight concentrated at the hub. Therefore, reducing weight at the rim, such as through the use of lighter rims, tires, and tubes, leads to a more noticeable improvement in acceleration compared to reducing weight at the hub. This enhanced acceleration translates to a bike that feels more responsive, particularly when starting from a standstill, accelerating after corners, or making quick changes in pace. The rider will experience a more immediate feeling of speed and efficiency when using lighter wheels.

The Effect of Wheel Weight on Climbing Ability

When cycling uphill, the rider must overcome the force of gravity pulling the bicycle and rider downwards. The total weight of the system, including the bicycle and its components, directly affects the effort required to ascend a gradient. Lighter overall bike weight, which is directly influenced by the weight of the wheels, makes climbing easier as less energy is needed to increase the bicycle’s gravitational potential energy – its energy due to its position in a gravitational field. The effect of weight is more pronounced on steeper climbs, where the force of gravity acting against the rider’s forward motion is greater. Lighter wheels contribute to better climbing performance by reducing the total mass that the rider needs to propel uphill. This reduction in weight translates to a higher power-to-weight ratio for the rider, allowing for faster climbing speeds and reduced fatigue on longer ascents. Even a seemingly small reduction in wheel weight can accumulate to a significant advantage over the course of a long or steep climb.

Wheel Weight and its Influence on Overall Ride Feel

Beyond the objective measures of acceleration and climbing, the weight of bicycle wheels also has a noticeable impact on the subjective feel of the ride. Lighter wheels often contribute to a feeling of nimbleness and agility, making the bike easier to handle and more responsive to rider input, particularly during quick maneuvers and changes in direction. This can enhance the overall riding experience, making the bike feel more lively and engaging. Conversely, heavier wheels tend to maintain momentum better once they are up to speed, providing a more stable and planted sensation, especially at higher velocities on flat terrain. This characteristic can be advantageous for maintaining speed on rolling roads or during sustained efforts. Ultimately, the preferred wheel weight often comes down to the rider’s individual preferences and the type of riding they primarily engage in. Riders who prioritize quick acceleration and climbing performance might favor lighter wheels, while those who value stability and momentum on flatter terrain might find heavier wheels more suitable.

Durability and Impact Resistance: Material and Construction Considerations

The durability and impact resistance of bicycle wheels are critical for ensuring rider safety and the longevity of the equipment. These characteristics are heavily influenced by the materials used in the wheel’s construction, primarily aluminum alloys and carbon fiber composites, as well as the specific construction techniques employed.

Aluminum Alloy Wheels: Durability Characteristics

Aluminum alloys have been a long-standing material choice for bicycle wheels due to their relatively low cost, good strength-to-weight ratio, and inherent durability. One of the key advantages of aluminum in the context of durability is its behavior under impact. When subjected to a significant force, aluminum tends to deform or dent rather than fracturing or cracking catastrophically. This ductile nature can be beneficial in real-world riding scenarios where impacts from potholes, rocks, or other road hazards are possible. A dented aluminum rim might still be rideable, at least temporarily, allowing the cyclist to continue their journey. In some cases, minor dents in aluminum rims can even be repaired. This resilience under impact has contributed to aluminum’s reputation as a durable and robust material for bicycle wheels, particularly among riders who frequently encounter rough terrain or prioritize long-term reliability over the ultimate in weight savings or aerodynamic performance.

Carbon Fiber Composite Wheels: Strength and Failure Modes

Carbon fiber composite wheels have gained immense popularity in high-performance cycling due to their exceptional stiffness-to-weight ratio, which translates to improved acceleration, climbing, and often aerodynamic efficiency. Modern carbon fiber wheels produced by reputable manufacturers have also made significant strides in terms of durability and can withstand a considerable amount of riding stress. However, the primary difference in durability compared to aluminum lies in carbon fiber’s behavior under severe impact. While carbon fiber is very strong for its weight, it is also more brittle than aluminum. This means that when subjected to a harsh, direct impact, a carbon fiber rim is more likely to crack or break rather than simply dent. A cracked carbon fiber rim is generally considered unsafe to ride and typically requires replacement. While advancements in carbon fiber technology and manufacturing techniques are continuously improving the impact resistance of carbon wheels, this difference in failure mode remains a key consideration for cyclists when choosing between aluminum and carbon fiber. Riders who prioritize ultimate performance and are willing to be more cautious about impacts might opt for carbon, while those who prioritize robustness and a more forgiving material under impact might prefer aluminum.

The Role of Construction Techniques in Enhancing Durability

The overall durability and impact resistance of a bicycle wheel are not solely determined by the material of the rim but are also significantly influenced by the wheel’s construction techniques. For spoked wheels, the way in which the spokes are laced from the hub to the rim plays a crucial role in distributing loads and absorbing impacts. Spoke lacing patterns with a higher number of crossings, such as 3-cross and 4-cross patterns, tend to create stronger and more durable wheels by more effectively distributing pressure applied to the rim. These patterns help to prevent excessive stress on any single spoke or area of the rim, thereby increasing the wheel’s ability to withstand impacts without failure. In the realm of carbon fiber wheels, manufacturers are continually developing advanced construction techniques to improve impact resistance. For example, Venn Cycling reinforces high stress areas around spoke holes and valve stem to better withstand impacts and sudden increases in spoke tension. Independent testing laboratories often conduct impact tests on bicycle wheels to evaluate their ability to withstand various levels of force without cracking or sustaining significant damage. These tests provide objective data on the durability of different wheel designs and materials, helping consumers make informed decisions based on their riding needs and the types of impacts they might encounter.

Reputable Cycling Journals, Publications, and Independent Testing Labs

For cyclists and researchers seeking reliable and unbiased information on bicycle wheel design, several reputable resources offer technical analyses and objective evaluations. These sources prioritize scientific evidence and engineering principles over commercial marketing claims.

Technical Analyses in Cycling Journals and Publications

Several cycling journals and publications are known for their in-depth technical analyses of bicycle components, including wheels. The Journal of Science and Cycling is an academic journal that publishes research across various aspects of cycling science, including equipment performance. While its primary focus might not be exclusively on wheel design, relevant articles based on scientific studies can be found within its publications. Popular cycling magazines such as Cycling Weekly and BikeRadar also feature technical reviews of bike components, often including detailed assessments of wheelsets. These publications typically conduct their own testing and provide performance analyses, although it’s important to be mindful of potential advertising influences. Gran Fondo Cycling Magazine is another reputable resource that offers in-depth reviews and often conducts group tests of various cycling components, including high-performance wheels, focusing on criteria like aerodynamics, stiffness, and handling. These publications generally aim to provide riders with comprehensive and objective evaluations to aid in purchasing decisions.

Independent Testing and Evaluation Organizations

Independent testing laboratories play a crucial role in providing objective evaluations of bicycle wheel performance and durability. EFBE Prüftechnik GmbH, based in Germany and Taiwan, is a leading laboratory specializing in mechanical testing of bicycles and their components. EFBE’s proprietary TRI-TEST program goes beyond established national and international standards, subjecting components to rigorous fatigue, maximum load, overload, and stiffness tests to simulate the stresses encountered throughout a bike’s lifespan. Reports from EFBE provide valuable data on the structural integrity and safety of bicycle wheels. SGS is another global organization that offers comprehensive testing and certification services for bicycles and e-bikes, including components like wheels. SGS tests against various international standards, evaluating mechanical strength, braking performance, electrical safety (for e-bike wheels), and the presence of hazardous substances. Manufacturers often seek SGS certification to demonstrate the safety and quality of their products. Mavic, a well-known wheel manufacturer, also conducts extensive in-house lab tests on their wheels, focusing on reliability, resistance to impacts, and endurance, often exceeding the requirements set by the UCI. Additionally, Mavic has published findings from their tests on counterfeit wheels, highlighting the safety risks associated with non-genuine products. These independent testing labs and the technical analyses found in reputable cycling publications provide valuable resources for understanding the objective performance characteristics of bicycle wheels, free from the biases of commercial marketing.

Physics and Engineering Principles Behind Bicycle Wheel Design

The design and performance of bicycle wheels are rooted in fundamental principles of physics and mechanical engineering. Understanding these principles provides a deeper appreciation for how different design choices impact the wheel’s behavior and overall cycling experience.

Fundamental Mechanical Principles

Bicycle wheels function as complex mechanical systems that operate under a variety of forces and moments. The primary force acting on a wheel is the radial load, which is the weight of the rider and the bicycle transmitted through the hub to the rim via the spokes. Lateral forces arise during cornering and from crosswinds, acting sideways on the wheel. Torsional forces are generated during pedaling and braking, causing a twisting action between the hub and the rim. Additionally, impact forces are encountered when the wheel strikes bumps or other obstacles on the road surface. The materials used in the wheel’s construction, such as aluminum alloys and carbon fiber composites for the rim, and steel or carbon fiber for the spokes, possess specific material properties (e.g., Young’s modulus, tensile strength, density) that dictate how they respond to these forces. A key concept in understanding spoked wheels is that they function as prestressed structures, where the spokes are under tension, creating a stable and strong assembly. This tension allows the wheel to support radial loads effectively; as the wheel rolls and a spoke comes under the hub, the tension in that spoke decreases, but ideally, it does not go to zero. The remaining tension in the other spokes supports the load.

Engineering Considerations in Wheel Design

Designing an optimal bicycle wheel involves navigating a complex landscape of engineering trade-offs. Achieving low weight often comes at the expense of durability, while maximizing aerodynamic efficiency can sometimes compromise stability in crosswinds. Engineers must carefully consider the intended use of the wheel and the likely demands it will face when making design choices. For example, a wheel designed for road racing might prioritize low weight and aerodynamics, potentially accepting a trade-off in ultimate impact resistance. Conversely, a wheel intended for mountain biking might prioritize durability and strength over marginal gains in weight or aerodynamics. Modern bicycle wheel design heavily relies on sophisticated engineering tools and methodologies. Finite Element Analysis (FEA) is used to simulate the structural behavior of the wheel under various loading conditions, allowing engineers to optimize the design for stiffness, strength, and weight. Computational Fluid Dynamics (CFD) is employed to analyze the airflow around different rim shapes, enabling the development of aerodynamically efficient designs. Material selection is another critical aspect of the engineering process, with engineers carefully choosing aluminum alloys or carbon fiber composites with specific properties to meet the performance and durability requirements of the wheel. The design of the hub, the dimensions and lacing pattern of the spokes, and the overall geometry of the rim are all meticulously engineered to create a wheel that performs optimally for its intended purpose.

Synthesis and Conclusion: Towards an Optimized Bicycle Wheel

This literature review has explored the intricate relationship between various design aspects of bicycle wheels and their impact on performance, stability, and durability. A clear consensus emerges regarding the significant influence of rim design on aerodynamic drag, with deeper and carefully shaped rims offering substantial reductions in air resistance. However, this advantage often comes with increased side forces, affecting stability, particularly in crosswinds. The interaction between rim width and tire width is also critical for aerodynamic efficiency, with a growing trend towards wider rims supporting wider tires for a balance of performance characteristics.

Spoke design plays a vital role in wheel stiffness, which directly impacts handling and power transfer. Higher spoke counts generally increase stiffness, but at the cost of added weight. Spoke material has a less direct effect on stiffness than spoke gauge, although carbon fiber spokes offer potential weight and fatigue life advantages. Lacing patterns influence torsional stiffness and can be optimized for specific performance goals, with crossed patterns generally favored for torque transfer.

Wheel weight is a crucial factor affecting acceleration and climbing ability, with lighter wheels offering a noticeable advantage in these areas, especially when weight is reduced at the rim. The choice between aluminum and carbon fiber for rim material often involves a trade-off between the impact durability of aluminum and the superior stiffness and weight savings of carbon fiber. Construction techniques, including spoke lacing and rim manufacturing processes, are also vital in determining the overall strength and durability of the wheel.

Reputable cycling journals and independent testing laboratories provide valuable, unbiased evaluations of bicycle wheel design, offering data-driven insights into performance and safety. The design of bicycle wheels is ultimately an exercise in engineering optimization, requiring a careful balance of various performance characteristics based on the intended application and the specific needs and preferences of the rider. Ongoing research and technological advancements continue to push the boundaries of bicycle wheel design, promising further innovations in the pursuit of enhanced performance, stability, and durability.

References

1. Carbon Vs Aluminum Alloy Wheels: How to Choose & Upgrade Bike Wheels - The Pro’s Closet. https://www.theproscloset.com/blogs/news/how-to-upgrade-your-wheels
2. (PDF) Drag and Side Force on Bicycle Wheel-tire Combinations - ResearchGate. https://www.researchgate.net/publication/323909534_Drag_and_Side_Force_on_Bicycle_Wheel-tire_Combinations
3. Aerodynamics of High Performance Bicycle Wheels - University of Canterbury Research Repository. https://ir.canterbury.ac.nz/items/8f84fd22-1091-4261-a965-7b5fc8fabbe4
4. Bicycle Wheel Aerodynamics Predictions Using CFD: Efficiency Using Blade Element Theory - ERAU Scholarly Commons. https://commons.erau.edu/cgi/viewcontent.cgi?article=1092&context=aiaar2sc
5. Aerodynamic Bicycle Wheel Design Optimization - CAESES. https://www.caeses.com/blog/2020/aerodynamic-bicycle-wheel-design-optimization/
6. Mechanical Engineer Looks at a Bike Wheel, Bucks Tradition and Redesigns It - Engineering.com. https://www.engineering.com/story/mechanical-engineer-looks-at-a-bike-wheel-bucks-tradition-and-redesigns-it 7. What do you put between your aero rim and tire? - Equipment - TrainerRoad Forum. https://www.trainerroad.com/forum/t/what-do-you-put-between-your-aero-rim-and-tire/41443
7. Inside Rim Width for Pure Road - Weight Weenies Forum. https://weightweenies.starbike.com/forum/viewtopic.php?t=173779
8. What is rolling resistance and why does it matter? - BikeRadar. https://www.bikeradar.com/features/tech/rolling-resistance-explained
9. Rolling Resistance | Schwalbe Tires North America. https://www.schwalbetires.com/technology-faq/rolling-resistance/
10. Influence of wheel rim width on rolling resistance and off-road speed in cross-country mountain biking - FOLIA (University of Fribourg). https://folia.unifr.ch/unifr/documents/324352 12. The Rim Width Test Road bike, CX/gravel, and MTB tires - Bicycle Rolling Resistance. https://www.bicyclerollingresistance.com/specials/rim-width-test
11. Wheel Stiffness Test - Sheldon Brown. https://www.sheldonbrown.com/rinard/wheel_index.html
12. Wheel Stiffness by BikeRaceInfo. https://bikeraceinfo.com/tech/wheel-stiffness.html
13. (PDF) Measuring vertical tyre stiffness of bicycle tyres - ResearchGate. https://www.researchgate.net/publication/376108366_Measuring_vertical_tyre_stiffness_of_bicycle_tyres
14. Measuring vertical tyre stiffness of bicycle tyres - DiVA portal. https://www.diva-portal.org/smash/get/diva2:1818249/FULLTEXT02.pdf
15. Spoke Tension and Vertical Wheel Stiffness - Killa’s Garage. https://www.killasgarage.bike/uncategorized/spoke-tension-and-vertical-wheel-stiffness/
16. Spoke count and comfort - Weight Weenies Forum. https://weightweenies.starbike.com/forum/viewtopic.php?t=175461
17. Wheels – Vertical Compliance, Lateral Flexibility - Killa’s Garage. https://www.killasgarage.bike/uncategorized/wheels-vertical-compliance-lateral-flexibility/
18. Debunking Wheel Stiffness - Slowtwitch News. https://www.slowtwitch.com/Tech/Debunking_Wheel_Stiffness_3449.html 21. Rolling Resistance Measurements on Cycleways Using an Instrumented Bicycle | Journal of Cold Regions Engineering - ASCE Library. https://ascelibrary.org/doi/10.1061/%28ASCE%29CR.1943-5495.0000244
19. (PDF) Bicycle-Wheel Spoke Patterns and Spoke Fatigue - ResearchGate. https://www.researchgate.net/publication/242257064_Bicycle-Wheel_Spoke_Patterns_and_Spoke_Fatigue
20. effect of spoke type on wheel stiffness - Weight Weenies Forum. https://weightweenies.starbike.com/forum/viewtopic.php?t=125588
21. Calculating bicycle wheel stiffness and stresses - dashdotrobot.com. https://dashdotrobot.com/blog/calculating-bicycle-wheel-stiffness-and-stresses/
22. Spoke lacing for most laterally stiff wheel? - Weight Weenies Forum. https://weightweenies.starbike.com/forum/viewtopic.php?t=98433
23. SPOKE LACING: What makes Sense and what is Nonsense! Efficiency Comparison using Advanced Engineering software - article comments | BikeGremlin Forum. https://www.bikegremlin.net/threads/spoke-lacing-what-makes-sense-and-what-is-nonsense-efficiency-comparison-using-advanced-engineering-software-article-comments.121/
24. How does the spoke weaving pattern of a road bike enhance wheel strength? - ICAN Cycling. https://icancycling.com/blogs/articles/how-does-the-spoke-weaving-pattern-of-a-road-bike-enhance-wheel-strength
25. Science of Cycling: The Wheel (Page 2 of 3) - UAF Physics. https://ffden-2.phys.uaf.edu/211.fall2000.web.projects/J%20Krizek/index%20page%202.html 29. The Physics of Wheel Building - Bike Components Blog. https://www.bike-components.de/blog/en/guides/the-physics-of-wheel-building/
26. Wheel Trick Four - Power - Wheel Fanatyk Blog. https://wheelfanatyk.com/blogs/blog/wheel-trick-four-power
27. Nerd Alert - Finite Element Analysis of Spoke Lacing Patterns - Slowtwitch Forum. https://forum.slowtwitch.com/forum/Slowtwitch_Forums_C1/Triathlon_Forum_F1/Nerd_Alert_-_Finite_Element_Analysis_of_Spoke_Lacing_Patterns_P6526657/ 32. Lighter wheels vs heavier wheels experiment - Bicycles Create Change. https://www.bicyclescreatechange.com/wp-content/uploads/2017/04/Wins-Report-Lighter-wheels-vs-heavier-wheels-experiment.pdf
28. Will Lighter Wheels Make You Faster When Cycling - Pedal Chile Blog. https://pedalchile.com/blog/light-wheels
29. How much effect does the mass of a bicycle tire have on acceleration? - Physics Stack Exchange. https://physics.stackexchange.com/questions/18725/how-much-effect-does-the-mass-of-a-bicycle-tire-have-on-acceleration
30. Nerding Out: Why You Shouldn’t Worry Too Much About Weight - Pinkbike. https://www.pinkbike.com/news/nerding-out-why-you-shouldnt-worry-too-much-about-weight.html 36. Technical FAQ: Does wheel weight matter? - Velo. https://velo.outsideonline.com/road/road-racing/technical-faq-does-wheel-weight-matter/
31. How do bicycles work? The science behind this ‘simple’ machine - Pitsco Education Blog. https://www.pitsco.com/Blogs/News/how-do-bicycles-work-the-science-behind-this-simple-machine 38. Carbon MTB Wheels: Are They Worth it vs Aluminum MTB Wheels | The Pro’s Closet Blog. https://www.theproscloset.com/blogs/news/are-carbon-mtb-wheels-worth-it
32. Aluminium or carbon wheels: our tips for road, gravel and mountain bikes - The Cyclist House Blog. https://www.thecyclisthouse.com/en/blogs/news/carbon-or-aluminium-wheels-tipps
33. Journal of Science and Cycling - SciSpace. https://typeset.io/journals/journal-of-science-and-cycling-5p8bb57r 41. Journal of Science and Cycling | Scilit. https://www.scilit.net/journal/9317 42. Bike wheel reviews | Cycling Weekly. https://www.cyclingweekly.com/reviews/bike-components/wheels
34. EFBE Prüftechnik GmbH | Engineering for Bikes. https://www.efbe.de/en/ 44. EFBE TRI-TEST. The ultimate reference test. https://www.efbe.de/en/tri-test-en.html 45. How We Test Our Cargo and Passenger-Carrying Bikes for Safety - Tern Bicycles. https://www.ternbicycles.com/en/explore/product-safety/how-we-test-our-cargo-and-passenger-carrying-bikes-safety 46. E-Bike Certifications—The Ones That Really Matter for Your Safety - Tern Bicycles. https://www.ternbicycles.com/us/explore/product-safety/e-bike-certifications-ones-really-matter-your-safety
35. 12 High-End Frames in the EFBe Fatigue Test - Sheldon Brown. https://www.sheldonbrown.com/rinard/frame_fatigue_test.htm
36. Test Report - Bicycle / E-Bike Frame EFBE Sample No. 208249 - t Mannetje. https://www.tmannetje.nl/local/userfiles/rover-recall/test_result_Rover_frame_EFBE_Passed_P208249_versie_2.pdf
37. Bicycle and E-bike Testing - SGS. https://www.sgs.com/en/services/bicycle-and-ebike-testing
38. Bicycle and E-bike Testing | SGS USA. https://www.sgs.com/en-us/services/bicycle-and-ebike-testing
39. Comprehensive e-Bike Testing Services - SGS PDF. https://www.sgs.com/en/-/media/sgscorp/documents/corporate/brochures/sgs-cp-ebike-testing-services-hr-en.pdf 52. About UCI & SGS Proved - Superteam Wheels Blog. https://superteamwheels.com/blogs/superteam-articles-carbon-wheels/about-uci-proved
40. EMC testing of pedelecs and e-bikes in accordance with EPAC/EMC standard EN 15194 - SGS CQE. https://www.sgs-cqe.de/en/service-portfolio/emc-testing/pedelecs-and-e-bikes.html 54. Menaggio 2014 EN14781 Test Report from SGS - Issuu. https://issuu.com/prolite/docs/menaggio_2014_sgs_en14781
41. SGS Approved-MOSTSPORT Road Carbon Wheels [Attached Test Report]. https://www.mostsport.com/news-posts/sgs-approved-mostsport-road-carbon-wheels-attached-test-report/
42. Mavic buys and tests a “replica” of its own wheels: “These counterfeit wheels are dangerous and will lead to serious injury or death” - Brujulabike.com. https://en.brujulabike.com/mavic-testing-fake-wheels-2021/
43. An analytical model to study the radial stiffness and spoke load distribution in a modern racing bicycle wheel - ResearchGate. https://www.researchgate.net/publication/245388002_An_analytical_model_to_study_the_radial_stiffness_and_spoke_load_distribution_in_a_modern_racing_bicycle_wheel
44. Bicycle Wheel Spoke Patterns and Spoke Fatigue - Duke University. https://people.duke.edu/~hpgavin/papers/HPGavin-Wheel-Paper.pdf 59. The Science of Bikes - NC Parks. https://www.ncparks.gov/education-programs/nc-culture-kids/falls-lake-state-recreation-area-bikes-discover-more/open 60. Bicycle science - how bikes work and the physics behind them - Explain that Stuff. https://www.explainthatstuff.com/bicycles.html
45. Bicycle Wheel - Brandt (PDF) - Rexresearch1.com. https://rexresearch1.com/BicycleLibrary/BicycleWheelBrandt.pdf
46. Introducing engineering: 2.4 Bicycle structures | OpenLearn - The Open University. https://www.open.edu/openlearn/science-maths-technology/introducing-engineering/content-section-2.4
47. The Science behind Ultra-Wide Rims - Rene Herse Cycles Blog. https://www.renehersecycles.com/the-science-behind-ultra-wide-rims/
48. Bicycle testing - STEP Lab. https://step-lab.com/bike/
49. What is bicycle safety standards testing | ACT LAB Blog. https://act-lab.com/a-guide-to-bicycle-safety-testing/