How Do Bike Trainers Work? Easy-to-Understand Explanation

Bike trainers may seem like complicated devices, but their principle is 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 used for indoor cycling 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.

Wheel-on trainers allow you to mount your bike without removing 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

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 by 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 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 is 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 electricity to provide you with the desired features.

Examples of magnetic bike trainers: Elite Novo Force (read review), Sportneer Bike Trainer (read review), Saris Magnetic Bike Trainer
Examples of electromagnetic bike trainers: Wahoo KICKR (read review), Tacx Flow, Saris H3 (read review)

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.

Examples of fluid bike trainers: Saris Fluid2 Trainer, Kinetic Road Machine Smart 2, Elite Turno

In the following table, I summarized the advantages and disadvantages of all resistance types.

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

Conclusion

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.