Bike trainers may seem like complicated devices, but their principle is pretty simple. They need to provide you with resistance when pedaling.
However, there are many types of bike trainers and resistance types.
So, I researched this topic, spoke with experts, and wrote this easy-to-understand article on how bike trainers work to satisfy your curious mind.
Let’s dive in.
What Is a Bike Trainer?
A bike trainer is a bicycle accessory that allows mounting a bike and riding it while remaining stationary.
In addition, they provide resistance when pedaling. Smart trainers can measure your ride data and transmit them to 3rd party apps.
Bike trainers are sometimes called ‘turbo trainers’ or ‘training stands.’
Wheel-on trainers are sometimes called ‘dumb trainers.’
How Do Bike Trainers Work?
All bike trainers work on the same principle. Their main goal is to provide you with resistance when pedaling.
There are two basic types of attaching your bike to the bike trainer’s frame:
- Wheel-on bike trainers
- Direct-drive bike trainers
Wheel-on trainers allow you to mount your bike without the need to take off your rear wheel. The rear wheel is then set up against a roller that provides resistance.
Direct-drive trainers require you to take off the rear wheel. These trainers have a cassette and an axle to attach your bike.
NOTE: You can learn more about the benefits and disadvantages of these two mechanisms in my how to choose a bike trainer article.
Types of Resistance
Trainers use one of the following four resistance types.
- Wind resistance
- Magnetic and electromagnetic resistance
- Fluid resistance
Before diving deeper into individual resistance types, let me quickly explain the difference between linear and progressive resistance.
Linear resistance is typical for magnetic bike trainers. Their resistance increases linearly.
In other words, the resistance doesn’t increase with how fast you pedal. Instead, the trainer’s flywheel gains momentum, making pedaling easier.
Wind and fluid bike trainers feature progressive resistance. This means the faster you pedal, the higher the resistance.
This type of resistance simulates outside riding conditions more realistically.
See the following chart for a better idea.
Wind Resistance Bike Trainers
Wind-resisted bike trainers use a fan that creates resistance as it spins through the air. The faster you pedal, the higher the resistance.
There is no way to regulate the resistance of wind trainers except how fast you pedal and what gear you use.
Wind bike trainers are not very popular anymore because they are noisy and don’t allow you to change the resistance based on your training’s needs.
Examples of wind bike trainers: Cycleops Wind Trainer
Magnetic and Electromagnetic Resistance
Magnetic bike trainers use magnets to slow down the flywheel. The closer the magnet to the flywheel, the higher the resistance, and vice versa.
You can manually regulate the position of the magnet via the control knob (also called resistance selector) that you mount on the handlebar.
Electromagnetic bike trainers also use magnets to slow down the flywheel*, but they are controlled electronically via 3rd party apps.
This means that they can simulate climbing, descending, or riding on flats, depending on the terrain you ride in the indoor cycling app.
*The flywheel can either be physical (found on most smart interactive bike trainers) or virtual (typical for Tacx NEO 2T).
Interactive smart trainers require an electricity source to provide you with the desired features.
TIP: Read this in-depth comparison of magnetic vs. fluid bike trainers.
Fluid Resistance Bike Trainers
Fluid bike trainers are almost like wind bike trainers, but they use a liquid chamber with an impeller instead of an air-resisted fan. As the impeller moves through the liquid, it creates progressive resistance. This results in almost unlimited resistance.
Check out the following video to get an idea of how the inside of the fluid resistance unit looks.
In the following table, I summarized the advantages and disadvantages of all resistance types.
|Type of Resistance||Pros||Cons|
• Progressive resistance
|• Very noisy
• Lack of resistance adjustability
|Magnetic||• Relatively affordable|
• Quieter than wind trainers
• Manually adjustable resistance
|• Linear resistance
• Maximum resistance level
|Electromagnetic||• Adjustable resistance based on 3rd party apps|
• Very quiet
• Require electricity
|Fluid||• Progressive resistance translating into|
a very realistic riding feel
• Quieter than wind and magnetic trainers
• No maximum resistance level
• Lack of resistance adjustability
I recommend reading my in-depth guide to learn more about other features of bike trainers and how to choose one.
How Do Bike Trainers Work FAQ
I hope you have a better idea of how bike trainers work and the differences between individual resistance types.
If you consider buying one, feel free to read my guide on choosing a bike trainer, where you learn more about their features and which ones to consider based on your needs.
Or, you can browse the best bike trainers on the market to save time doing the research. I already did it for you.
Do you have any further questions regarding bike trainers? Let me know in the comments, and I will do my best to answer it.