Flywheels have become a hot topic in the world of fitness.
This relatively “new” workout device has revolutionized eccentric training by making it safer and easier.
I’ve been training with flywheels since 2020 with the Exxentric kBox4, a fantastic platform-based flywheel device.
Exxentric is a pioneer of the modern flywheel design, and since their formation in 2011, they’ve developed several flywheel products.
While I think the kBox4 is the best for general flywheel training, it has limitations that the kPulley addresses.
For example, the kPulley opens up a variety of horizontal movements, rotational movements, and bodybuilding movements like triceps pushdowns, face pulls, and more.
In this review, we’ll closely examine the kPulley Go. I’ll take you through its features and detail my experience with the product. By the end, you should be able to tell if it’s right for you.
Let’s dig in.
An Overview of Eccentric Training & Flywheels
Eccentric training, also known as “training the negative,” is a deliberate effort to train the lengthened portion of a movement. In weight training, there is a concentric portion (lifting the weight/shortened position) and an eccentric portion (lowering the weight/lengthened position).
Physics and anatomy tell us that a lengthened muscle is stronger and more capable than a shortened muscle. Therefore, it makes sense to train the stronger portion to increase muscle size and strength. However, the issue is that to train the eccentric, you must first get past the concentric.
Do you see the dilemma?
If your muscle can handle 50lbs in the eccentric but can only lift 35lbs to get there, how can you take advantage of your true capacity? You can do it in three ways:
- You can have a partner help you lift the weight while you lower the weight by yourself
- You can bilaterally lift the weight while unilaterally lowering the weight
- You can use a flywheel
Flywheels are unique training devices because they use inertia and force responses to generate both eccentric and concentric stimuli. Instead of relying on gravity like traditional weight-lifting, flywheels use variable kinetic energy. In other words, the amount of energy you put into the flywheel on the concentric, you receive back on the eccentric.
Flywheels are very simple mechanisms. A belt is attached to a driveshaft that holds one or more inertia plates. When you start a movement, the belt will unwrap around the driveshaft until the concentric portion is complete. With energy flowing through the system and a flywheel that’s rotating quickly, the belt is retracted and begins to wrap around the driveshaft.
The retraction marks the eccentric portion of the movement. All the energy you built up during the concentric must be absorbed and reversed on a 1:1 basis during the eccentric. Once you absorb and decelerate this force, you quickly begin a new concentric phase, repeating the process until you stop.
Because you control the amount of energy on every concentric rep, the load is always variable and always unlimited. The flywheel design creates a safer and more effective way to train the eccentric portion of a lift. Hence its rising popularity.
Regardless of your training goals, a flywheel can help you achieve them. Powerlifters looking for strength, bodybuilders looking for hypertrophy, athletes looking for sport-specificity, and anyone looking for prehab/rehab for injuries can benefit from flywheels.
Now that you understand how and why flywheels work, let’s get into the kPulley Go, specifically.
The Exxentric kPulley Go
The kPulley Go is arguably Exxentric’s most versatile offering because you can use it virtually anywhere due to its size and mounting options.
Unlike the platform-based kBox4, which uses a more vertical line of pull from the bottom, the kPulley Go can be set up at various heights with multiple angles of pull. This creates a lot of training variety, especially with upper-body and rotational movements.
It’s also much smaller and lighter than the kBox4, making it easier to store and transport.
On the other hand, it’s not as easy to set up as the kBox, nor is it an effective substitute for movements like squats, deadlifts, and more – all of which shine with the kBox.
Ideally, a flywheel enthusiast will have both to maximize utility. That said, if you’re looking for a space-friendly solution with a focus on upper-body exercises, the kPulley Go is a great option.
Exxentric designed the kPulley Go after the kpulley2 but with an emphasis on accessibility. While the kPulley2 is adjustable across multiple heights, it’s a more fixed system. The kPulley Go was developed to provide similar versatility but with multiple attachment options. It’s a more compact, less rigid, and less costly version of the kPulley2.
Like all Exxentric products, the kPulley Go is built with high-quality materials. The main body is constructed with a combination of formed and welded steel, and it measures 8.75″ long x 5″ tall x 6″ wide.
In the center of the device is a large cutout with a steel driveshaft running through the center. This shaft houses a pre-installed heavy-duty belt, which you can adjust based on the movement you’re performing and the device’s height. On the bottom of the device is a hanging Y-channel that routes the belt and secures it into position.
By pulling down on the hanging belt, you can quickly increase the belt’s length. To shorten the length, while not as quick, you lift the pin via two red end caps and pull from the other side. For example, a rowing movement can use a shorter belt length than a triceps pushdown.
For me to adjust the length, it only takes a second or two. The issue is that it can be difficult to know exactly where to stop the adjustment by eyeballing it alone. You will probably have to adjust the length, test it, and then adjust it again to get it perfectly dialed in. A good idea would be to mark your belt with a marker based on ideal lengths for the movements you perform the most.
To get the belt moving for the exercise, you can simply pull from the attachment block. This is usually enough to get the belt to wind or unwind. However, you can always spin the plate with your hand to jump-start it. To stop the exercise, don’t grab the plate. Instead, decelerate gently and follow the belt toward the device until it comes to rest.
On the back of the device is a long pin that’s dropped into your mount of choice (see more on mounting options below). This pin, secured with a threaded end cap, allows the kPulley Go to pivot laterally, making dynamic movements possible and comfortable.
Protruding from the side of the device is the plate-loaded section of the driveshaft. Behind it are two rounded plastic threads you can tighten to hold a plate shield. While this is technically optional, I recommend installing it to prevent injury from inadvertently hitting the plate while in motion. The shield adds an extra 5″ to the overall length and 10″ to the height.
The kPulley Go can be mounted in three ways, making it the most accessible product Exxentric carries. Regardless of which mount you choose, the main device clips into the mount with a long pin. On the rack and Beam mounts, the device can be partially height-adjusted with a pop pin without having to move the mount.
The rack mount is the most appealing option for home gym owners. This didn’t exist when the kPulley Go first launched, but Exxentric listened to feedback and added it as an option later.
Exxentric built the rack mount for 3×3 squat racks with 1″ holes and 2″ spacing. It has two pins that you insert into the rack. On the ends of the pins are two steel hinge brackets. When rotated 90 degrees, they lock into place to provide a very secure mount.
While I love the versatility of the rack mount, Exxentric could improve the fitment. The first issue is that some racks, like the REP PR-5000, use the metric system while others, like the Rogue RM-6, use the imperial system. Despite both racks being “3×3 with 1″ holes,” the measurements are slightly different since they use different systems of measurement.
Therefore, the spacing between the holes is also slightly different. To ensure a proper fit, you must notify Exxentric in a comment box at checkout which rack system you own. In my case, I have both imperial and metric racks. And because I have the imperial rack mount, it doesn’t fit well on my metric-based REP rack. I have to physically hammer it into place (with a rubber mallet, of course).
The second issue is that it doesn’t fit 5/8″ holed racks, which is a very popular size for home gym owners.
I would love to see Exxentric adjust this mount by using smaller pins to accommodate these variances and open up the option for racks with 5/8″ holes. The Ancore Training System has a clever mounting system that you can use on 1″ or 5/8″ holed racks with spacing ranging from 1″-4″. A similar system on the kPulley Go would appeal even more to home gym owners.
All kPulley Go orders include a strap mount. It includes a primary bracket with two strap channels at the top and bottom. Once routed, you can use the straps to attach the bracket to any fixed object.
This system makes the kPulley Go very portable, truly allowing you to train anywhere – indoors or outdoors. It also comes with a back plate that you can mount directly to your wall, giving you a permanent spot for your kPulley Go. However, this isn’t a route I recommend for most since you’re limited to one height.
The Beam is an Exxentric product that acts like an upright of a squat rack. It can be attached to a stud in your wall with lag screws, or it can be attached to something vertical with attachment straps (sold separately by Exxentric).
The Beam allows the device to adjust up and down easily using the Beam Adapter (also sold separately). You can purchase the Beam in four sizes (S, M, L, XL), ranging in height from 15.4″ to 88.6″.
If you have a good spot on your wall and you don’t want to take up rack space, I recommend the Beam. It’s less you have to deal with when setting up your rack, and it’s easier to use.
The kPulley Go can be loaded with five different plates:
- Extra Small – 0.005 kgm²
- Small – 0.010 kgm²
- Medium – 0.025 kgm²
- Large – 0.050 kgm²
- Extra Large – 0.070 kgm²
I own two large plates and one each of the XS, S, and Medium. Exxentric recommends that you don’t exceed two extra large plates, which is plenty of resistance for the movements you’ll perform on this device.
These steel plates have a hexagonal center hole that fits perfectly on the driveshaft. Once loaded, the knob is attached to the shaft to secure the plates.
Each plate has a nice-looking gray finish with a black center border that includes the size and inertia level. Each plate also comes with a bag to protect them while not in use.
You pick each plate based on your training goals and the movements you’re performing. Exxentric has an in-depth article on plate selection, but here are a few rules of thumb:
- Low inertia is great for warm-up and power movements.
- Medium inertia is great for technique work as well as strength and eccentric overload.
- Higher inertia is great for strength and eccentric overload.
The kPulley Go doesn’t have nearly as many accessory options as the kBox4. That’s not to say it’s not as versatile, though – it just does different things. Here are a few accessories that come with the device:
- kGrips – The kGrips are simple D-handles that open up numerous pushing and pulling movements. Row variations and pressing movements are ideal candidates. These handles are included in any kPulley Go order.
- Ankle Cuffs – The ankle cuffs are also available in every order. As the name implies, these wrap around your ankles, opening up isolated lower body exercises like hamstring curls, leg raises, and more.
- Rotational Sling – The Rotational sling is only available in the kPulley Go Advanced System, but you can purchase it separately. The sling is a comfortable attachment that wraps around one shoulder and then around your waist. You can use it to build core strength and power by rotating your body against the inertia resistance. This is a great accessory for athletes who have to perform rotational movements in their sport: golf, baseball, tennis, hockey, etc.
Aside from these, Exxentric also sells high-quality attachments like the kBar and others. Of course, you can use any cable attachment you may already own or prefer.
Price & Packages
There’s simply no denying that flywheels are expensive. Exxentric is certainly no exception – in fact, they’re among the most expensive. But with that comes excellent build quality, great resources, and a very smooth experience. Still, it’s not going to be for everyone – especially anyone looking to build a budget home gym.
The Starter System comes with the device, the strap mount, one medium flywheel, kGrips, and Ankle Cuffs. It’s priced at least $300 under the Advanced System.
The Advanced System includes everything in the Starter System plus the beam adapter, attachment choice (beam or rack), two additional flywheels (you pick the size), and the rotational sling. Depending on how you build the Advanced System, it could be as much as $700+ more than the Starter System.
If you’re serious about flywheel training and want more attachment options and plates, the Advanced System is the way to go. If you already own plates and plan on strap-mounting the device, I recommend the Starter System.
My Experience with the Exxentric kPulley Go
I’ve been using the kPulley Go since March 2022. Unlike my first experience with flywheels and the kBox4, I knew what to expect. Flywheel training has become one of my favorite modalities, and I’ve found it easy (and fun) to program it into my regular weight-based training.
If you’re new to flywheel training, Exxentric offers a ridiculous amount of education and resources to help. There is a learning curve with operating a flywheel – mainly in getting it moving and managing effort and intensity.
Remember, inertia-based flywheel training is very different than traditional weight lifting. One way you’ll immediately know that is with pauses. In weight training, we’ll often pause at the end of a concentric, whether to reestablish our breath or increase time under tension. In flywheel training, there is no pause after the concentric because the energy immediately flows into the eccentric, which you must absorb rapidly. If you try to pause after a concentric, you could injure yourself. You’ll get the hang of it quickly.
Since there’s an added height variable compared to the kBox, I’ve found it more difficult to get the belt set up for some movements. There’s a little more trial and error before getting into the movement itself. As mentioned above, marking the belt with a contrasting color can help with movements you commonly perform.
As for using the kPulley Go, it’s been a welcomed addition to my training. While I love the kBox4 and use it often, there are things you can do with the pulley that aren’t possible with the box. Being able to perform triceps pushdowns, triceps extensions, face pulls, horizontal rows, single-arm chest presses, and more has been great.
I’m also really enjoying the rotational sling. As someone who golfs, it’s been great for developing downswing power and even grooving hip rotation. If you’re someone who plays other rotational-based sports, I would highly recommend buying the advanced system or at least purchasing this separately.
While there are plenty of other movements you can perform on the kPulley from a low position, I prefer the kBox on almost all of them. Biceps curls are a good example – they work just fine on the pulley, but I like the more vertical positioning that the kBox allows. Bent over rows and leg raises are two other examples.
The kPulley Go requires more setup time than the kBox, but it’s been a tradeoff I’m happy to accept for the additional versatility. I wish the rack mount was universal so I could use it more easily on both of my rack systems. Furthermore, more goes into setting up the device on a rack (moving j-cups, spotters, etc.). If I could go back, I would have elected for the Beam to create a dedicated flywheel area instead.
In any case, I’m very pleased with the product, and I’m getting great use out of it.
Shipping & Assembly
The kPulley Go is shipped in a single box with a very protective custom-cut insert. Each piece of the device is neatly packed, and there’s virtually no movement inside the box. It’s one of the best packing jobs I’ve seen.
Assembly is very straightforward. Exxentric provides a thorough manual that walks you through assembly and more. The most important part of the assembly is properly routing the belt (refer to image above).
Once unboxed, I was using the kPulley in about 10 minutes.
- Exxentric is the leading flywheel manufacturer
- The kPulley Go is space-friendly and lightweight
- Multiple attachment options allow the device to be set up virtually anywhere
- The lateral pivot makes dynamic movements possible and comfortable
- Excellent build quality with high-end parts, excellent machining, etc.
- Wide variety of movement options, especially in the upper body
- Five different plate sizes allow users to choose based on training goals
- Expensive for the average home gym owner
- The rack-mount system could be improved to create a universal adapter, thereby accommodating more rack types
- Adjusting belt length takes longer because of the added height variable.
I’ve been a big fan of flywheel training since first using the kBox in 2020. The kPulley Go is a great compliment to the kBox since it opens up so many upper body movements.
It’s a very well-made device with loads of utility and a compact footprint. It’s easy to set up and break down, and it’s light enough to store and travel with.
If you like the idea of flywheel training and you want a solution that offers a lot of upper body variety, I strongly recommend the kPulley Go.
FAQs About the kPulley Go
What is the Exxentric kPulley Go?
The kPulley Go is a high-quality, adjustable, and portable flywheel device that can be mounted virtually anywhere. This unique training tool can be used for upper and lower body training and relies on inertia instead of traditional weight lifting.
Is the kPulley Go Worth it?
The kPulley Go is worth it if you train with flywheels, need an upper body solution, and want a space-friendly option that you can set up anywhere. Exxentric is a leader in the flywheel industry, and they’ve designed the kPulley Go as a premium offering.
Does Flywheel Training Work?
Eccentric training has been scientifically shown to increase muscle size, strength, hypertrophy, and assist in rehab/prehab. Flywheels are the safest and most effective way to train the eccentric portion of a lift, making them a very valuable tool.