Nautilus U618 Upright Bike (Model 100653) is ridden by a male athlete

Nautilus U618 Upright Bike (Model 100653) Review

There are preceding models to the Nautilus U618 Upright Bike (Model 100653), and these are the Nautilus U614 and Nautilus 616 Upright Bikes. These previous models, as expected, do not have some of the features the Nautilus U618 (Model 100653) has.  

However, the Nautilus U616 has a lot in common with the Nautilus U618, and it’s inexpensive and popular among users. The differences between these two are not much. Basically, the U618 is integrated with an upgraded handlebar that has resistance adjustment buttons, has a different set of pedals. It’s a lot more compact and could support a higher user weight than the U616.  

The Nautilus U618 Upright Bike model 100653 is the newer 2018 model. The older version with model number 100493 came out in 2016 and is still available on the market. Interestingly, Nautilus also released R618 Recumbent Bike and T618 Treadmill in 2016 and subsequently released the upgraded versions in 2018 as well.  

Click right here to have a peek at the price of the Nautilus U618 100653 on Amazon.  

The Frame and Construction 

Nautilus U618 Upright Bike (Model 100653) is ridden by a female athlete

Nautilus U618 is durable, sturdy, and stable due to its design, and the quality of the components it possesses. Thus, it supports 325 pounds/147 kg maximum user weight capacity. It is a light commercial-grade upright bike with a solid steel frame that takes everything that is thrown at it.  

The visible steel components of the bike are coated with anti-corrosive paint in a bid to prevent rusts and indiscriminate scratches that could degrade and shorten longevity and distort appearance in the long run.  

Whereas, the drive system cover, the base stabilizer bars’ end covers, and the water bottle holder that is attached to the console mast are all made of quality plastics.  

The bike has a smaller footprint and is weightier than its predecessors. Its overall assembled dimensions are 38.6 inches long by 24 inches wide by 58.3 inches high. So, this means that a workout or a storage area with a perimeter of 3’3’’ long by 2’ wide and a ceiling height of at least 7-8′ high will contain the bike.  

However, in the case of the workout area, additional extra clearance of 1-2′ at the rear and on each side of the bike will be necessary, so that the user can exercise with optimum safety and convenience. Therefore, when considering where to exercise with the bike take into account the extra space that might be required. This is imperative especially if the bike is to be used in a confined area.  

Despite the bike’s small footprint, its stability is awesome. For the most part, this is because of the base framework that features triangular-shaped steel stabilizer bars. There are also adjustable levelers underneath the rear stabilizer bar which enable the user to level up the bike on a surface that is not even.  

The front base bar is integrated with transport wheels for easy relocation of the bike.  

Moreover, the bike weighs about 83 pounds/36.7 kg, which nevertheless boosts the overall stability.  

Users of different fitness levels can mount and dismount the bike easily and conveniently due to its easy step-thru design. 

The Seat 

Seat of the Nautilus U618 Upright Bike (Model 100653)

The Nautilus U618 Upright Bike (Model 100653) is equipped with a more comfortable seat.  

The seat is contoured and cushioned with 2 gel seat covers, one on either side of it. They are designed to provide a lasting comfort that endures through a long workout session and users have applauded the seat’s comfortability.  

One can adjust the seat in 4 different ways; in other words, it’s 4-way adjustable (upward, downward, fore, and aft). The seat post has 14 different adjustment positions that allow users between the heights of 5’3’’ to 6’7’’ to be accommodated.  Although users less than 5’3’’ could use the bike, but there might be the issue of not being able to conveniently reach the pedals in a certain workout posture(s). 

The Handlebar 

The handlebar on the Nautilus U618 100653 is unique and different from the one on the 2016 model. It has a multi-grip design that allows a user to work out in different postures or angles that target different muscle groups.  

There are also large pads for resting the elbows while working out and resistance control buttons at the tip of the handlebars that enable the user to easily adjust the intensity of the workout on the fly.  

The handlebar is 2-way adjustable; that is, it could be adjusted upward/downward. However, it is possible to tilt it backward or forward through the knob at the center of it.  

There are EKG sensors on the handlebar for tracking and transmitting the heart rate data to the monitor when held during a workout. Although, the console is also telemetry enabled, which means you may use the heart rate chest strap (included in the package) for the pulse tracking instead.  

The handlebar is generously coated with a soft rubber foam that prevents blisters and slippage that could be caused by sweaty palms. Ultimately, a user can work out safely, comfortably, and longer.  

The Pedals 

The pedals on this upright bike are weighted and anti-skid designed with adjustable safety straps. These accommodate barefoot or standard gym shoes and they provide good alignment and safety for the knees and the feet.  

They can accommodate most foot sizes.  

But if for any reason you wish to change the pedals for another you can because they have a standard thread.  

The Drive 

The belt drive system of the Nautilus U618 Upright Bike (Model 100653)

The Nautilus U618 Upright Bike (Model 100653) is equipped with a belt drive system. Consequently, its operation is smooth and quiet.  

It is so quiet when operating the bike that no one around will feel disturbed. A user can watch a favorite TV show/movie or listen to the radio without having to raise the volume beyond the normal range.  

The drive system consists of a durable anti-stretch v-belt, 3-piece crankset, solid crank-arms, pulleys, and a 30-pound/13 kg flywheel that could be considered heavy (in a good way) for an upright bike. So, due to the heavy flywheel, the motion is characterized by a steady momentum.  

Users can perform out-of-seat pedaling, but it’s not recommended and not entirely safe because it is originally designed for seated workouts.  

The drive system is maintenance-friendly. Differently put, no- post lubrication or adjustment is required. 

The Resistance 

The bike is incorporated with an electromagnetic eddy-current resistance system with 25 levels. It consists of a servo motor and a magnetic property. This is not manual and does not work if not plugged into a power source.  

The resistance is controlled via the buttons on the console or the handlebar. It can also be engaged automatically when a certain built-in program is selected. 

There are sufficient resistance levels that support users of different physical fitness which include seniors, beginners, intermediaries, advanced athletes, and those undergoing physical rehabilitation.  

Users with the intentions of attaining specific goals of losing weight, improving cardiovascular health, strength and endurance will be able to do so with the bike.  

The Console 

Nautilus U618 Upright Bike (Model 100653) console

The Nautilus U618 Upright Bike (Model 100653) is equipped with an adjustable sightline console that could be tilted for a better view and it features DualTrack blue backlit monitors. The two screens display data with high readability that could not be compromised even when viewed in a poorly lit room.  

There is a large and a small screen on the console; the large top screen displays the current workout profiles, selected goal, and the heart rate interval. While the smaller screen tracks the basic workout data such as the time, speed, distance, RPM, calories burned, resistance level, and heart rate.  

Interestingly, speed and distance can be tracked in miles and km/h. 

There are 4 user profiles available that enable up to 4 different users to store settings such as height, weight, age, gender, and name, separately. These user profiles are also capable of storing workout results for future reference. 

The console has 29 customizable workout programs for interval training, heart rate training, weight loss training, and more. These typically help anyone to achieve fitness goals. 

As aforementioned, the console is telemetry enabled. This means heart rate monitoring can be done using a compatible heart rate chest strap, even though, there are EKG sensors on the handlebar that also offer heart rate tracking.  

Nautilus U618 Upright Bike (Model 100653) is Bluetooth enabled

The console is also Bluetooth-enabled. This allows the user to sync a tablet device or a computer with the console in order to transfer workout data from the bike to the external device which has the MyFitnessPal installed on it for better workout tracking.  

There is a USB media charging port available as well, which could be used for this purpose in case you are unable or don’t want to connect via Bluetooth and it is also used for charging purposes.  

You will also be able to connect to the RideSocial app that enables you to compete in real-time with other users around the world.  


The console features other accessories for your convenience. These include an adjustable cooling fan, built-in speakers, a media charging port, and a tablet holder.  

There are also water bottle holders on the console mast right below the handlebar.  

All these are designed to let you work out productively with less boredom.

Pros/Features Overview 

  • Sturdy construction that supports a high user weight capacity 
  • Compact and portable 
  • Has an appealing design 
  • Easy step-thru design 
  • LCD monitor are two screens, backlit and tracks a wide range of workout data 
  • The seat is very comfortable and 4-way adjustable 
  • The handlebar is duly coated with soft rubber foam for comfort and it’s 2-way adjustable with 
  • Users with different heights can be accommodated 
  • There are 4 user profiles for 4 different users personal information entry 
  • There are 29 programs for weight loss training, interval training, heart rate training and more 
  • 25 resistance levels suitable for everyone at any fitness level 
  • The console is Bluetooth enabled; sync the bike with a tablet or computer for data transfer to MyFitnessPal app and compete with other users via the RideSocial app 
  • The console is telemetry enabled; can monitor the heart rate by using a chest strap (included) 
  • EKG contact sensors are also available for heart rate monitoring 
  • Easy to assemble 
  • Low-maintenance 
  • Cooling fan included 
  • Tablet holder included 
  • Water bottle holders included 
  • A USB charging port 
  • Great warranty 


  • Requires to be plugged to a power source before it can be used  
  • If a tablet is placed on the holder, the large screen display might be blocked and cannot be viewed



  • 15 Years on the Frame 
  • 3 Years on the Parts 
  • 1 Year on Labor 

Product Dimensions and Specifications 

  • Length 38.6’’ 
  • Width 24’’ 
  • Height 58.3’’ 
  • Supports 325 pounds/147.4 kg maximum user weight capacity 
  • Assembled weight: 83 pounds/37.6 kg 
  • Drive: Belt 
  • Resistance: Electromagnetic, 25 levels 
  • Bluetooth enabled 
  • Connection to MyFitnessPal and RideSocial apps 
  • Programs: 29 
  • Telemetry and contact heart rate monitoring enabled 
  • Blue backlit DualTrack LCD monitor  
  • Seat: 4-way adjustable with gel seat cover 
  • Handlebar: 2-way adjustable with large elbow pads 
  • Transport wheels: Yes 
  • 3-speed fan: Yes 
  • Media tray/tablet holder: Yes 
  • Built-in speakers: Yes 
  • Water bottle holders: Yes 


The Nautilus U618 Upright Bike is shipped in a box that weighs 90 pounds/40.8 kg and it is shipped free of charge by Amazon.  

Delivery is made within a couple of days from the day of order. 


The assembly of this bike is pretty straightforward and easy. Although it comes not completely assembled, however, the hard part has been done by the manufacturer.  

Thus, you only need to attach the seat and the handlebar posts, the seat, the handlebar, the front and rear stabilizer bars, the pedals, and the console to the core unit. The assembly takes about an hour, more or less.  

An instruction manual that walks you through the process of the assembly and the tools needed for the job are included in the package.  


The bike needs to be kept clean from dust and moisture at all times. Do not expose the console to water or moisture to avoid malfunction.  

Ensure to examine the bike before use for any loose or broken parts. This prevents an accident and further damage to the bike.  

Other necessary warnings are detailed in the owner’s manual.  


The Nautilus U618 Upright Bike is embellished with a lot of features such as 29 programs, 25 resistance, Bluetooth capability, online connectivity, and more. These help the user to engage in exercises designed for achieving specific fitness goals.  

It has customizable features that allow users of different heights to be accommodated and 325 pounds/147.4 kg user’s weight is supported.  

Nautilus U618 Upright Bike (Model 100653) Review
618 min1

Nautilus U618 is durable, sturdy and stable due to its design, and quality of the components it possesses. Thus, it supports 325 pounds/147 kg maximum user weight capacity.

Product Brand: Nautilus

Product In-Stock: InStock

Editor's Rating:

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