Spin Bike Flywheel & How to Pick The Best One

When one pictures an indoor bike, one of the biggest parts that sticks out in the mind is most likely the large wheel that either sits in front or in back. After all, bikes need wheels, don’t they? Even the indoor ones. These wheels are known as flywheels and can really affect just how a spin bike feels and runs underneath you.

Today we’re going to look at some of the differences in various types of flywheels and examine the benefits and disadvantages they give to the spin bike they are attached to. With that out of the way, let’s hop right into our spin bike flywheel comparisons.

1. Lightweight Flywheels

To start us off, we must examine what the job of a flywheel is. Quite simply, it is there to simulate the feel of an outdoor bike by storing energy to smooth the cycling motion. To get somewhat technical for a moment, this kinetic energy is a product of mass and speed. Physics says that larger and heavier flywheels store more energy. However, in practicality, the lightweight flywheels spin faster and provide more energy on account of this speed. This is the approach that Keiser has taken with their M3 line of spin bikes, which are widely regarded as being high quality. These flywheels are designed to have enough inertia to provide a smooth and challenging ride without being too aggressive and rocking the body.

Another benefit of the lighter flywheels comes in the form of how they affect the actual pedal strokes and muscles. These flywheels can actually promote both hamstring and glute improvements thanks to the fact that they do have more power while weighing less. Considering how many people actively seek to use these sorts of bikes for glute and hamstring improvements, this is perfect for the cyclist – experienced or new. Note: Light flywheels require the combination of high-gear ratio and magnetic resistance (not friction resistance) to deliver smooth top-notch pedal strokes.

The Pros:

• The lighter flywheels have a higher amount of energy that can be produced thanks to their ability to spin fast.
• They are easier to move around and can work out the areas of the body that cyclists desire.
• There is less bearing and belt maintenance with lightweight flywheels.

The Cons:

• Lighter flywheels can be on bikes that are more expensive (they require higher gear ratio drive, double pulley design, and magnetic resistance to work smoothly).
• Considering how popular they have become in the top tier manufacturers’ list of features, this really is no surprise.

2. Heavyweight Flywheels

On the flip side, there are heavier flywheels. These flywheels give the bike a lot of momentum to build on. However, it also makes the bike heavier and harder to move around. Since it is heavier, it also adds extra pressure on the bearings and belt of the spin bike. In turn, this makes it more likely that the spin bike will require more regular maintenance.

It might sound like we are disapproving of the heavyweight flywheels, but that isn’t the case. They can still certainly provide excellent workouts. However, it just happens to be the case that they do not provide quite the same amount of maximum power that the lighter flywheels can. It certainly isn’t like some of the top spin bike brands aren’t using these sorts of flywheels. Stages, who is one of the top manufacturers of spin bikes, has bikes that contain flywheels up to 50 lbs. These heavier flywheels do make movement on the spin bike less jerky and more controlled. Another benefit of these heavier flywheels is that the spin bike resistance can also go higher into the upper levels. Note: If you end up buying a spin bike with friction resistance (not magnetic), make sure the flywheel is heavy, preferably more than 30-lbs.

The Pros:

• They allow for more controlled movements during the exercise.
• The speed is high, though not as high as the lighter flywheels.
• The resistance available on these flywheels can also go quite high.

The Cons:

• Bikes with these heavy flywheels can require more maintenance than those with lighter flywheels.
• It also makes the bikes harder to move around due to weight.

3. Rear Drive Flywheels

Now we get into the position of the flywheel. This can be quite important as well, since the positioning of the flywheel can determine how long it will last. Rear drive flywheels, unsurprisingly, are those that have their flywheel located in the rear. This means that they are away from the front, where the console and handlebars are. More importantly, this means that they are away from what is called the “sweat zone”.

With a name like that, we bet you can’t guess what happens here… or can you? We’ll tell you anyway. It is the zone in which you sweat and that sweat is likely to drop down onto the flywheel. This sweat can then make the flywheel require more bike maintenance, which really is not ideal. When looking for a spin bike that will last for some time, you will most likely want to look for one with a rear drive flywheel.

The Pros:

• These flywheels are located outside of the sweat zone, improving their ability to last over a longer amount of time.
• They often come with 100% inclosed flywheel which makes them safer if there are kids in the house.

The Cons:

• These rear-drive flywheels are also difficult to master in terms of their feel and settings.
• It’s not as easy as front-drive bikes to tilt up and move them from one place to another place.

4. Front Drive Flywheels

Of course, while the rear drive flywheel spin bikes have an advantage of being outside the sweat zone, that doesn’t mean that front drive flywheels are completely useless. They can certainly still provide an excellent workout on whatever bike you happen to be riding on.

They also will not all suddenly crash and explode simply because they got a few beads of sweat dropped on them. It is just more likely that they will have more problems down the line if a large amount of sweat is dropped on them without any sort of care taken to wipe it down or make sure that the sweat is taken care of.

The Pros:

• The more traditional wheel setup, allowing for an easier transition for those who are used to the wheel in front.
• Easier to move them from one place to another place.

The Cons:

• They are more vulnerable to sweat erosion for those who do not take time to keep the wheel maintained.
• Often they are not fully shrouded/covered which makes them less safe than fully enclosed rear flywheels.

5. Fixed Flywheel

And now we get into the fixed flywheel versus free flywheel debate. An interesting aspect of this design choice is that many people don’t even seem to know what this means or take it into account when choosing a spin bike. Part of this reason is because many do choose to go with a fixed flywheel, so there isn’t even really a choice to be made. However, we feel it’s important to explain it and keep people informed on what these sorts of flywheels can do.

The pedals on a fixed flywheel are used to get the wheel moving. This seems fairly straightforward, since that’s sort of the entire deal that pedals offer. However, what many people don’t realise is that once it is moving, the wheel itself is actually propelling your feet around in a circle. This means that it is not like traditional bikes, where you can freely take your feet off, coast along and otherwise take small breaks in the midst of the workout.

This fixed flywheel actually helps burn more calories because you need to pedal continuously until the end of the workout. For those who prefer to carry on with long, uninterrupted cycling workouts and exercise programs, then bikes with these fixed flywheels are most likely the better option.

The Pros:

• The fixed flywheel forces you to finish the workout by not allowing frequent breaks during the ride. Thus, more calories are burnt with these flywheels.
• It is also the type of flywheel most people who ride spin bikes are used to.
• Fixed-gear (fixed flywheel) allows the rider to pedal forward and backward (with resistance) and work on different muscle groups.

The Cons:

• For those who like breaks or the ability to coast during their rides, this is not an ideal piece of equipment.
• In case of emergency, you can’t immediately hop off. You have to first stop the flywheel/pedals, then you can leave the bike.

6. Free Flywheel

On the flip side, there is the free flywheel. The free flywheel is much more akin to that of a wheel that you would find on a traditional, outdoor bike. It allows you to take your feet off of the pedals while the wheel continues to spin. This gives the feeling of coasting and allows for much more frequent breaks.

One of the benefits that these types of flywheels give is their ability to compliment high intensity interval training (HIIT) exercise programs. Since breaks are actually able to be taken while on the spin bike, you can take a break before launching back into an intense bit of cycling.

One of the arguments against fixed flywheels is also that because the flywheel is powering along with the pedals, it is “stealing” some of your workout. If you’re not powering along all of the effort behind what is being put forth in the session, are you really getting the most out of it? We find this argument a tad silly, but it is technically right in that the wheel propels the pedals and it is not all the power of your feet.

The Pros:

• This is a more traditional type of flywheel. It allows for coasting and a feeling more akin to outdoor bikes.
• Those who like HIIT training would love these types of flywheels.
• In case of an emergency, you can jump off the bike without having to wait for the flywheel to stop.

The Cons:

• It is not as good for those who prefer the traditional spin bike flywheels or want to be pushed to the end of their workout.
• Spin bikes with freewheel flywheels are more expensive than fixed flywheel spin bikes.

7. Flywheel with sweat protection guard

Finally, we get to the aspect of the flywheel that is important, but rarely thought about. For those flywheels that do tend to be on the front end of the spin bike, it is important that it has some sort of protection against falling sweat. Especially if the bike has non-magnetic resistance. Wool resistance bands can be particularly vulnerable to sweat deterioration. As such, these flywheels can be extremely valuable on such a bike. Yet, many people do not know about this and end up making their bike have a much shorter life span than they otherwise could. If the flywheel or bike with one of these friction resistance systems starts making annoying noises or starts feeling unnatural, then it might be time to invest in some sort of protection for the flywheel. Worst case scenario, the flywheel or the brake pads might need to be replaced, which nobody really wants to happen.

The Pros:

• It protects your flywheel from damage, especially if the friction resistance system is made of wool.
• Fully inclosed flywheels are safer and keep the curious fingers away.

The Cons:

• It can be irritating to keep in good shape.

8. Flywheel without sweat protection guard

As we just mentioned, this is the standard. Not many bikes have sweat protection built into their flywheels. In fact, the only ones that need it are those front wheel systems. That’s why, if you are getting one of these non protected flywheels that is sitting in the sweat zone, you might want to investigate getting some sort of protection. There is zero benefit to having a flywheel that is vulnerable to sweat. It simply deteriorates quicker and leads to more frustration down the line. Nobody wants their piece of exercise equipment to break, especially if they have invested a good deal of money into it.

The Pros:

• There are no pros here.

The Cons:

• With no protection, you would simply be exposing a flywheel to unnecessary risk of decay.
• With a friction resistance system and a front-drive flywheel, protection is basically a must.

FAQ

Q: What are the standard flywheels on spin bikes?

A: That’s one of the most interesting parts about spin bikes; there is no real standard for what the flywheels are. On the top tier brands that are moving into Matrix-esque levels of technology, you can find examples like the Tacx NEO Smart Bike that has a virtual flywheel. Meanwhile, others like the Keiser spin bikes go with lightweight, rear-drive fixed flywheels. Almost any combination you can think of can be found on a flywheel somewhere on the market.

Q: How do I find out what sort of flywheel a bike has?

A: Generally all it takes is a quick Google search in order to find out the specific qualities of a spin bike. Either on the manufacturer’s website under specifications or on a separate review of the bike as a whole, these are good places to start looking for just what sort of flywheel you would be getting with the bike. If you are interested in finding out more specific details of the flywheel, then it might take a more intense search to find out every little characteristic that you can.

Q: How important is it that I focus on what sort of flywheel a bike has?

A: Honestly, it depends. If you are someone who is simply looking for a piece of exercise equipment that will allow you to get some workouts in while remaining at home, the only real aspects that you will want to look out for is whether or not the bike has a front-drive flywheel. If it does and has a friction-based resistance system, then you will want to see if it has sweat protection. This is because it is important to the long term durability of the spin bike. Otherwise, it really shouldn’t make too big of a difference. For those who are particular in what they want on these spin bikes, doing in-depth research on what sort of flywheel they want can really pay off for their fitness and cycling abilities.

Conclusion

That concludes our review of the different types and abilities that come with the flywheels on various home-use and commercial spin bikes. As you can see, they can make all the difference between having an excellent workout experience and one that is OK at best. As always, this should be treated as a guide rather than a rule of law. If you prefer the flywheel being in front, just be aware of the “sweat zone” and wipe down the flywheel frequently. We’re here to inform, not control. Now get out there and get cycling!

Sayed Hosseiny

Hi there, I'm Sayed Hamed Hosseiny, the founder and one of the authors at yourexercisebike.com (YEB). I am a former indoor cycling instructor and personal trainer with nearly 20 years of experience. With a passion for indoor cycling, I have spent years designing cycling parts, repairing, and importing exercise bikes. All the articles, tips, guides, reviews, and comparisons on YourExerciseBike.com (YEB) reflect my personal opinion and expertise in the field. I'm excited to share my knowledge with fellow exercise bike enthusiasts and help people find reliable indoor cycling information and the best exercise bike for their needs.

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