Fluid bike trainer vs Magnetic bike trainer (Comparison)

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In the times of this COVID pandemic, or during any moment that you are staying indoors – if you are an avid cyclist, you will be looking for efficient and effective ways to get some training done. Even though the excitement and feel on the ride will not be the same – you have to do what is necessary if you are a true professional. So as you are looking to begin indoor bike training, keep in mind that a setup that includes a quality trainer can work miracles for you. However, with the several trainers available nowadays, like electronic trainers, wind trainers, magnetic trainers, fluid trainers, and rollers as well. When given the option to choose between fluid & magnetic trainers, you should have sufficient knowledge about them to make the best choice. In this article, we will go through how fluid and magnetic bike trainers are similar, and what really sets them apart – which will in turn help you make the best choice.

What is a Fluid bike trainer?

Fluid bike trainer

Fluid bike trainers incorporate a flywheel and a roller. The shell on the exterior consists of a liquid. During pedaling, the wheels are pressing down on top of the roller. Further pedaling will heat up the fluid encased by the outer shell. This is because the pedal motion will allow the paddles present inside the shell to push on the liquid. Pedaling at more speed will only build up more resistance against the pedal strokes. With more pedaling, the fluid will provide more resistance(due to the change in its viscosity, that alters with any change in temperature of the liquid) and the more resistance you will feel in your pedal stroke. This sudden surge in resistance provides a more natural feel and increases the efficiency of your training. Another feature that helps fluid bike trainers to mimic the “road-feel” is the conservation of momentum. This will keep the flywheel rotating even if you are not pedaling. If you want to use the trainer more than once, no adjustments would need to be made to the resistance.

What are the advantages of using a Fluid bike trainer?

1. Quiet operation

Fluid bike trainers are considered to be the quietest among themselves and magnetic bike trainers. This is because the mechanism is dependent on liquid. Moving parts used traditionally tend to make a lot of noise.

2. Ride feel

When you are debating on a realistic ride, you are essentially talking about how similar the experience would be if you were riding the bike on the road itself. With hard pedaling, you will find that it is more difficult to push through the liquid.

When deciding which of the two trainers offer a more “realistic” ride – we would have to opt for fluid trainers. They are usually fitted with a WATT meter that will find an mph(miles per hour) equivalent for the wattage or “amount of effort”. Using this, you would be able to get a better look at how the feel on a fluid bike trainer is mimicking the feel of riding a bike on a fat road. Basically, you know the amount of wattage you would need to put in to go the corresponding “mph” reading.

3. No overpowering issue

Most of the fluid bike trainers do not offer the option to select the resistance. Instead, you will find that the mechanism of progressive resistance is being used here. This means that the harder you pedal, the greater amount of resistance is generated – similar to that in typical bicycles. This will challenge you as a rider. Therefore, even if your fitness is gradually improving, at no moment in time you will be able to “overpower” the trainer.

4. Flywheel

With the flywheel on fluid bike trainers, you will be able to coast on the pedals without halting your motion suddenly. This is crucial for cyclists who are more advanced and are looking to workout indoors to meet their training requirements. However, if you are an entry-level user, you do not need to pay much attention to this.

What are the disadvantages of a Fluid bike Trainer?

1. Not budget-friendly

Fluid trainers will stress your budget more than magnetic bike trainers since the highest quality of bike trainers use fluid resistance.

2. Leakage issues

Fluid leakage is a drawback you will have to face when you are using fluid bike trainers. Typically, the liquid inside the outer shell of the flywheel uses a seal to make sure that no fluid is let out. During operation, as viscosity changes – there is a high possibility that the seal fails to spill the silicone liquid inside. This temperature rise reduces the serviceable lifespan of the trainer.

3. Does not improve technical skills

Usually, we are just looking at the road-like feel that fluid bike trainers provide and pay little or no attention to how we are pedaling. As a result, we may be putting in more effort than we normally would when cycling outside. As we do so, we are more likely to experience fatigue faster as our legs go through a huge amount of tear and wear, which is not always necessary.

4. Might not be compatible with some bikes

Fluid bike trainers are usually not compatible with MTB bikes with wheels fitted with thru-axles. To make it compatible, you may need to purchase an extra part, which does not make the trainer cost-effective.

What is a Magnetic Bike Trainer?

Magnetic bike trainer

As indicated by the name, magnetic bike trainers are creating resistance against the motion of the bike wheel thanks to the magnetic flywheel. The flywheel has magnets that are revolving to create a certain amount of resistance as they are being engaged or disengaged. This is altering the resistance on the wheel here. To make adjustments to this magnetic resistance, you would need to get off the bike and choose the level you are looking to set the resistance too. This could also be achieved using a cable that has been mounted on the handlebars. This cable is attached to the trainer as well. Recommended for entry-level users. From gliding across smooth roads to going up a steep hill- anything can be simulated by changing the resistance.

What are the advantages of using a magnetic bike trainer?

1. Dependable

Since you are less likely to face “leakage” issues on magnetic bike trainers, they have longer service life-spans than bike trainers that are using fluid resistance. This is boasted by the manufacturers by the longer warranty periods offered with the machines.

2. Easy to set up

Typically, magnetic bike trainers can be set up easily for use. You would only need to attach a cable to the trainer’s body and mount it on the handlebars to modify the resistance level.

3. Ride quality

High-end models of magnetic bike trainers will offer drastically improved ride quality and will replicate the feeling of using an exercise bike at the gym. This can be favored by many users. These higher-end trainers also offer progressive resistance, which is dependent on how fast you are going on the pedals, eliminating the need for any selector switch.

4. Budget-friendly option

If you are simply looking to put in a lot of riding time on the bike trainer, magnetic bikes will provide more value for the money you would be spending on them. However, it is recommended that you opt for mid-range magnetic bike trainers for the smoothest workout sessions.

5. Ease of storage

Typically, they are designed to be lightweight and also foldable to facilitate storage.

What are the disadvantages of a magnetic bike trainer?

1. The ride feel is not realistic

Magnetic trainers are unable to replicate the feeling of a real-life bicycle. Owing to the constant resistance here, putting in more effort or bringing down pedaling intensity will not affect whatsoever. Unlike fluid trainers, you will not be able to coast on the pedals – as soon as you remove your feet from the pedals, the wheel motion will be halted as resistance will come into play.

2. Changing the resistance is a hassle

If you are an advanced trainer, you may be using the magnetic bike trainer for high-interval training workouts. However, as you have to get off the bike to make adjustments to the trainer, or install a cable that is attached to the trainer and is handle-bar mounted, neither of the stated methods allow for seamless changes to the resistance, which could be annoying for many users.

3. Noisy operation

These trainers make significantly more noise than a fluid trainer. As a result, discretion is never an option here. Even if you want to dampen the noise by placing the trainer on top of a mat – you cannot shut it out fully. You may have to think twice before using a magnetic bike trainer in a shared space, a condo, or an apartment.

4. Has a limit for effectiveness

We know that the resistance on magnetic bike trainers can be manually adjusted. However, as you see your fitness improvements over time – you may render the highest resistance setting useless. Therefore, you would not be able to use the trainer to make any further improvements to your fitness level.

5. Compatibility with frames and wheels

You will need to confirm whether this trainer can be adapted to an MTB bike. It is more likely that an adapter will need to be used with the thru-axle design on mountain bikes. However, in the short run- this adapter will emit a lot of noise and make the tire, less durable.

For your convenience, we have presented a summary of how fluid bike trainers and magnetic bike trainers are similar or different from each other in the comparison table below. This will help you to understand and make the best selection for yourself.

FeaturesFluid bike trainerMagnetic bike trainer
Working mechanismThe silicone fluid in the rear flywheel changes viscosity with changes in pedal power. Faster pedaling creates more resistanceThe flywheel has magnets revolving around which, which engage/disengage to create resistance. You can use a selector switch or a cable mounted on the handlebars to modify the resistance
Resistance levelProgressively challengingConstant for each setting
Ease of useEasyEasy
Noise factorLittle or no noiseNoisy
StorageSimple; may be foldedSimple; may be foldedbike trainers will
ReliabilityLeakage fail may occurDoes not fail easily
Budget friendlyNoYes


So, if we have to settle the debate between fluid vs magnetic bike trainers – to select the best machine, we have to look at what we are looking to get from each trainer. Magnetic bike trainers will be friendlier to the budget and allow for training longer. On the other hand, if you are looking for a more realistic ride feeling and the quality of the workout you are getting is a priority – fluid bike trainers will serve you better. Even though we are not settling the debate for you – we hope that this article will shed some light on the topic and help you choose better. Indoor riding can be as fruitful for a beginner as it is for expert users. If you are a beginner, the absence of any traffic will help your confidence. An expert user will try to train in workouts that are very specific and allow them to put in an effort. Irrespective of the goal you are looking to achieve – you can find a bike trainer to meet your needs exactly! So it is time you select the best trainer and “train” away to meet your goals.

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Dion Lewis

My name is Dion Lewis.I’ve been cycling since my childhood. When I was in high school, I started racing in our local competitions.In my college life, I took a part-time job in a bicycle shop and I learned how to repair and maintain bicycles professionally.Though I love racing, mountain biking is another thing I do frequently. My friends, neighbors, and colleagues treat me as an avid rider and take my suggestions while they plan for a new bike or bike gear.

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