What Does a Flywheel on an Exercise Bike Do?

Shopping for an indoor cycling bike is a lot more complicated than it used to be. In the last few...

Shopping for an indoor cycling bike is a lot more complicated than it used to be. In the last few years, technology and design has taken the humble exercise bike and transformed it into a high-spec piece of gym equipment. 

Of course, not everyone is looking for the same type of bike. Understanding the product specs will help make your buying decision easier, but what if you're not up to speed on the terminology used to describe key features? 

Flywheel weight is often included in product descriptions but what does a flywheel on an exercise bike do? 


What is a flywheel on a stationary bike?

The flywheel is the weighted disc that sits either at the front or back of a stationary bike. It connects to the pedals via a chain or a belt and stores the rotational energy generated during a workout. The rider begins pedalling, and the flywheel starts spinning. The momentum builds, and the flywheel supplies a smooth and steady cycling action.

What difference does the flywheel make on an exercise bike?

Flywheels come in different weights.

A heavier flywheel is harder to get moving, and riders must use more energy to get it rotating. This is similar to what happens on a road bicycle, where outdoor cyclists must put in more effort to move from a standing start. It takes more effort to get going than it does, keeping a steady speed once they're off and away. Heavier flywheels imitate the way a road bike works. It's why flywheel weight is often important to cyclists who train indoors during the winter. Once momentum builds and the cyclist gets into a rhythm, a heavier flywheel also allows for a smoother and more comfortable ride. Again, this is something else that's more consistent with outdoor cycling. Lighter flywheels are easier to get going, but the ride won't be as smooth.

The general recommendation is to opt for a heavier flywheel where possible. The RE:GEN has a flywheel of 15 kgwhich is within the average range for at-home stationary bikes. Commercial fitness bikes (the types you'll see in gyms and studios) usually range between 20 kg and 24 kg. But it really comes down to personal choice. Some people don't want or need to mimic outdoor riding. Bigger isn't better for everyone. Bikes with heavier fly wheel weights are harder to move around your property. They can be more expensive, too.

 How important are fly wheel weights? 

To the regular at-home or part-time gym cyclists? Probably not as much as you might think at first, but for serious cyclists then fly wheel weight will make an impact on riding experience. Of course, there will be other factors to consider including the type of resistance and torque transfer. 

Is an 8kg flywheel enough?

It will be for some people. Although, we'd recommend shooting for a weightier one unless you're a total beginner. 8kg is a little on the smaller side. The ride may feel rougher when you're pedalling at a faster speed. But again, it's down to personal choice, and anyone new to indoor cycling may feel more comfortable and confident using lighter fly wheel weights to exercise. Often lighter is cheaper, too. This can be a safe way of trying this type of exercise out before committing to a more premium bike. Although, this may not be the most economical choice overall. You may be better off buying once and buying better.

The RE:GEN's flywheel is 15 kg (33 pounds). This is about average for an at-home bike. Trying different flywheels before you buy can be helpful. You could always go to a store and try them out. You could also get a day pass at a gym and go for a spin on one of their bikes. You can then bring this information home and narrow down brands and models that use a similar weight.


Does Flywheel Weight Matter? 

It will depend on what type of workout you're hoping to achieve. Heavier flywheels take more effort to get moving, which, as we've mentioned, is generally preferred by outdoor cyclists or those people taking indoor cycling classes. Once the wheel is moving, it's easier to keep it going.

Fly wheel weights can also affect how smooth the riding experience is, with a heavier flywheel providing a better cadence at higher speeds. 

It's important to remember, though, that once the flywheel is moving, calorie burn and workout intensity can be decided by resistance and effort level. 

Flywheel weight is worth considering before you buy a bike, but it shouldn't be the only consideration. If you're looking for a bike on a budget, then you may have little choice but to buy something with a lighter flywheel weight. Companies are now much better, however, at manufacturing lighter wheels which still provide a smooth ride.


Can You Generate Electricity from an Indoor Bike's Flywheel?

Yes. People have always attached generators to static bike flywheels. The problem has been that the amount of power created is too small to be worthwhile. You'd have to do a lot of pedalling to generate a small amount of electricity.

There's a popular saying: sometimes the juice just isn't worth the squeeze. It's why electricity-generating indoor bikes for the home are easily dismissed. They're seen more as science projects than as potential clean energy sources, but Energym is changing that. 

The RE:GEN's flywheel captures the kinetic energy created during exercise and stores it inside a removable battery unit called The Ohm. The Ohm charges up during the exercise session, storing the clean energy so that it can be used later to charge phones, laptops, and more.


close up of an electricity generating indoor bike


But the RE:GEN is more than just an electricity-generating indoor bike. It's also loaded with added features that make it a stand-out static bike. For starters, the RE:GEN measures functional threshold power (FTP), is Zwift compatible, and allows users to earn Sweatcoins to spend on digital rewards and products. Pair the RE:GEN with the Energym app for A.I tailored workouts, games, online communities and virtual PTs. And, of course, not forgetting that the RE:GEN's clean energy generation helps reduce your carbon footprint. 

 You can find out more about the RE:GEN on the Energym website. 




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