Unveiling the Speed Impact of Dynamo Hubs!

Table of Contents:

1. Introduction
2. Overview of a Dynamo Setup
3. Components of a Dynamo Setup
4. Hub Drag with Nothing Connected
5. Impact of Dynamo Lights
6. Effects of USB Chargers
7. Comparing Different Dynamo Hubs
8. Predictions with More Powerful USB Chargers
9. Pros and Cons of Using a Dynamo Setup
10. Conclusion

Article:

Introduction

Have you ever considered using a dynamo setup for your bicycle? Dynamo setups offer the convenience of not having to worry about charging battery lights or sourcing power for your devices. However, you may wonder how much these setups will slow you down. In this article, we will explore the factors that affect drag and speed, the components of a dynamo setup, and the impact of different hubs, lights, and USB chargers. By the end of this article, you will have a better understanding of the trade-offs involved in using a dynamo setup.

Overview of a Dynamo Setup

A dynamo setup consists of various components that work together to generate power for your devices. The key component is the hub dynamo, which generates power by passing magnets over a copper coil. This process introduces some physical drag that affects your cycling speed. The efficiency and power output of the hub dynamos can vary, and we will discuss the lowest-drag hubs later in this article. In addition to the hub dynamo, a dynamo setup includes USB chargers and dynamo lights. USB chargers convert the power from the hub into a usable form for charging your devices. Dynamo lights, on the other hand, provide illumination while cycling. It is important to note that brighter lights tend to have a greater impact on speed due to increased drag.

Components of a Dynamo Setup

Before delving into the details of how a dynamo setup can affect your speed, let's take a closer look at the various components involved. As mentioned earlier, the hub dynamo is the primary component responsible for generating power. The efficiency and power output of hub dynamos can vary significantly, and it is important to choose one that balances power generation with minimal drag. USB chargers are another crucial component of a dynamo setup. They convert the power generated by the hub into a usable form for charging your devices. It is worth noting that the resistance at the wheel is determined by the power drawn by your devices. Therefore, the power output and efficiency of the USB chargers can also affect the overall drag. Lastly, dynamo lights play a significant role in a dynamo setup. Brighter lights tend to produce more drag, especially at speeds between 15 and 20 km/h. It is essential to consider the trade-off between illumination and speed when selecting dynamo lights.

Hub Drag with Nothing Connected

To understand the impact of a dynamo setup on your cycling speed, let's first examine the hub drag when no devices are connected. Different dynamo hubs have varying levels of resistance at different speeds. Most hubs tend to increase in resistance as your cycling speed increases, with the exception of the Schmidt SON hub, which offers a more steady drag across different speeds. However, in general, the drag caused by the hub with no devices connected is relatively imperceivable to a rider. On a flat road, a smaller rider may experience a slight decrease in speed between 14 and 54 seconds per hour, while a bigger rider may be between 7 and 43 seconds slower. On a climb, the drag increases, and the smaller rider may be 29 to 43 seconds slower, while the bigger rider may be 22 to 32 seconds behind.

Impact of Dynamo Lights

Dynamo lights are an essential feature of a dynamo setup, providing illumination for cycling at night. However, it is important to consider their impact on your speed. Brighter lights tend to slow you down more than dimmer lights. Most dynamo lights reach their maximum brightness, and consequently, produce the most drag, between speeds of 15 and 20 km/h. For our estimations, we will consider two different rider scenarios: a smaller rider weighing 60 kg and a bigger rider weighing 90 kg. On a flat road, a smaller rider with a bright 100-lux dynamo light may experience a time penalty of 2 minutes and 38 seconds to 3 minutes and 36 seconds per hour, depending on the hub. A bigger rider, on the other hand, will be less affected by drag, with a time penalty ranging from 1 minute and 48 seconds to 2 minutes and 24 seconds per hour. On a climb, the time losses increase, with the Shimano UR700 hub resulting in a penalty of 3 minutes and 22 seconds to 3 minutes and 47 seconds per hour. The SON28 hub, with approximately half the drag, will incur time losses between 1 minute and 41 seconds to 1 minute and 52 seconds per hour.

Effects of USB Chargers

Apart from dynamo lights, USB chargers also contribute to the overall drag in a dynamo setup. The power output and efficiency of USB chargers can vary, depending on their design. However, the resistance at the wheel is primarily determined by the power drawn by your plugged-in devices. For example, a Garmin GPS at a speed of 25 km/h would likely have significantly less resistance compared to a large smartphone. It is important to consider the power requirements of your devices when choosing a USB charger, as it can impact your speed. On a flat road, a smaller rider with a charger providing good power may experience a time penalty of 1 minute and 30 seconds to 2 minutes and 53 seconds per hour, while a bigger rider may face a penalty of 1 minute and 12 seconds to 2 minutes and 20 seconds per hour. On a climb, the time losses are slightly higher, with the smaller rider falling behind by 4 seconds to 2 minutes and 24 seconds per hour, and the bigger rider being 11 seconds to 1 minute and 48 seconds behind.

Comparing Different Dynamo Hubs

The choice of a dynamo hub can significantly impact the drag and speed of your bike. Different hubs offer varying levels of resistance and power output. In our estimations, we have compared the Shimano UR700 hub, which provides 25% more power at the USB plug than the SON hub, and the SON28 hub, which exhibits approximately half the drag of other hubs. On a flat road, the smaller cyclist may experience a time loss of 2 minutes and 13 seconds per hour with the Schmidt hub, while the bigger cyclist may be 1 minute and 34 seconds behind. On a climb, the smaller cyclist using the Shimano hub may be between 4 seconds and 2 minutes and 24 seconds slower per hour, while the bigger cyclist may be 11 seconds to 1 minute and 48 seconds behind.

Predictions with More Powerful USB Chargers

In this section, we will explore the potential impact of using a more powerful USB charger, such as the Cinq Plug5 Plus, in combination with a Schmidt SON hub. These predictions are based on charging efficiency data from the Schmidt hub and power output figures from independent testing of the Plug5 Plus. On a flat road, the smaller cyclist may be 2 minutes and 13 seconds behind per hour, while the bigger cyclist may lag by 1 minute and 34 seconds per hour. On a climb, the smaller cyclist may fall behind by 1 minute and 34 seconds, while the bigger cyclist may be just 1 minute and 8 seconds slower per hour. These predictions provide insights into the potential time losses when using a more powerful USB charger with a high-quality hub.

Pros and Cons of Using a Dynamo Setup

Using a dynamo setup on your bicycle offers several advantages, such as the convenience of not having to worry about charging battery lights or finding power sources for your devices. Additionally, dynamo lights provide illumination during nighttime rides, ensuring safety and visibility. However, there are also some drawbacks to consider. Dynamo hubs introduce drag, which can slightly decrease your overall speed, especially when using brighter lights or more power-hungry devices. Furthermore, the selection of components, including the hub, USB charger, and lights, can impact the overall efficiency and performance of the dynamo setup. It is important to weigh the advantages and disadvantages to determine if a dynamo setup is suitable for your specific needs and preferences.

Conclusion

In conclusion, a dynamo setup can offer the convenience of continuous power generation for your devices while cycling. While there is some drag introduced by the hub, USB chargers, and dynamo lights, the impact on your overall speed is relatively minimal for the average cyclist. Factors such as the weight of the rider, fitness level, bike weight, wheel size, and road surfaces also contribute to the overall drag. By carefully selecting the components and considering the trade-offs between speed and power generation, you can enjoy the benefits of a dynamo setup without significant sacrifices in your cycling performance.