Sunny Health & Fitness SF-B1852 Indoor Cycle

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Sunny SF-B1852

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L: 56.3"
W: 21.9"
H: 50"
350 lbs40 lbsManual
7 levels

The Sunny SF-B1852 is one of the indoor cycling bikes released by Sunny Health & Fitness in 2021. It’s basically an upgraded version of the Sunny SF-B1709. As opposed to the older model, the SF-B1852 comes with a heavier flywheel and has a greater maximum user weight limit. It also included a dumbbell holder and a device holder.

Key Features and Specifications

  • Assembled dimensions: 56.3L x 21.9W x 50H inches (143L x 56W x 127H cm)
  • Assembled weight: 127.6 lbs (57.8 kg)
  • Flywheel weight: 40 lbs (18 kg)
  • Supported weight: 350 lbs (159 kg)
  • Seat: 4-way adjustable
  • Drive: Belt
  • Resistance: Magnetic, 7 levels
  • Fitness monitor: Speed, average speed, max. speed, cadence, average cadence, max. cadence, time, distance, calories, pulse, race program
  • Extras: Bottle holder, dumbbell holder, device holder
  • Warranty: Frame 3 years / Parts 180 days

Frame construction

Although the Sunny Health & Fitness SF-B1852 is not a spin bike made for commercial use, it definitely has the construction and sturdiness of at least a light-commercial model. It features a V-type frame with an H-type base, similar to the Keiser M3i. However, the mid-section of the bike is completely covered by ABS guards.

The main frame of the bike is coated with a corrosion-resistant paint finish. The color used is black, this being the only color available for this bike, at least for the moment. The seat post and slider, the handlebar post, and the crank arms have a chrome finish. The flywheel is also chrome-plated but its edge is concealed by a circular guard and it also has ABS side guards.

The bike is a bit larger than most other similar models. However, it’s not a super large fitness machine. Its footprint is approx. 56.3″L x 21.9″W (143 x 56 cm), while its highest points is given by the top of the handlebars; at full extension, the handlebar reaches approx. 50″ (127 cm) above the floor.

The bike is considerably heavy. Its net weight is 127.6 lbs (57.8 kg). This being said, the transport of the packaged unit requires two people or at least a box trolley. However, once it is assembled, the bike can easily be moved by only one person. It front base bar is equipped with two large silicone wheels.

Due to its weight and low center of gravity, this Sunny Health & Fitness indoor cycling bike offers excellent stability. Plus, both its base bars have adjustable levelers with rubber pads that considerably improve its grip especially on a tile or laminated floor.

Seat and handlebars

The Sunny SF-B1852 indoor cycle includes a race-type saddle. Its dimensions are 10.6″L x 7.1″W x 2.8″H (27 x 18 x 7 cm). It’s built on a sturdy nylon shell. It integrates a layer of padding. It has a median groove for improved breathability. Also, its attachment system is standard collar-type. Thus, if you will ever want to replace it, you should be able to find a compatible one in most bike shops.

The bike’s seat is four-way adjustable (up, down, front, back). Its upright post offers several adjustment positions, while the horizontal slider adds 4 more front-to-back adjustment positions. Therefore, the applicable inseam range for this Sunny exercise bike is 28″ – 41″ (71 – 104 cm). In other words, the bike should accommodate users between 5’0″ – 6’4″ (153 – 193 cm) with no problem. It’s also rated for a maximum user weight limit of 350 lbs (159 kg).

The bike is equipped with a multi-grip handlebar similar to the one included with the Sunny SF-B1805 model. However, it only offers two-way adjustability (up, down). It does not have a horizontal slider like the seat, but its tube is slanted towards the user, so at its highest point, it’s also the closest possible to the user.

The handlebar offers the possibility to adopt a standard grip, a cruising grip, a climbing grip, a close parallel grip, and an aero grip. Its side grips integrate pulse sensors and the included fitness monitor unit can track your pulse. It is also covered by a layer of PVC foam for improved contact and comfort.

Drive system

The Sunny Health & Fitness SF-B1852 indoor cycling bike is equipped with a rear-drive system. It integrates a pretty heavy, 40 lbs (18.1 kg) flywheel, while many other exercise bikes with a similar design and a magnetic resistance system only have an 8-10 lbs (3.6 – 4.5 kg) flywheel. This is a plus, as the bike provides a very consistent pedaling motion even on the lowest settings which makes it great for leg muscle strength training.

The flywheel is bi-directional. It allows pedaling in reverse. However, just as for many other spin bikes, coasting is not possible on this bike, and when pedaling in reverse, you will get the same resistance as when pedaling forward.

The bike is equipped with a heavy-duty crankset featuring solid steel arms with a chrome plating finish. They’re also pretty long, promoting a healthy leg extension.

The included pedals are dual-sided. They have SPD elements for spin shoes on one side and toe cages on the other. They’re made from a durable metallic alloy so they can withstand pedaling while standing up, and just about any other spin workout. They also have standard 9/16″ threads, so in case you will ever want to replace them, compatible pedals are widely available.

The bike is equipped with a belt drive system. This means you don’t have to worry about taking the covers apart for drivetrain lubrication. Also, the belt delivers a smoother motion as it doesn’t generate as much vibration as a chain. It’s also quieter.

Resistance system

The Sunny Health & Fitness SF-B1852 is equipped with a manual magnetic resistance system. This means that you don’t need to connect it to a power source, and you don’t need a power adapter or power cord for it. But on the other hand, the bike cannot adjust the resistance automatically.

The resistance system consists of a magnetic brake concealed by the large frame guards. The brake is connected to the tension lever on top of the front frame tube through a steel cable. Therefore, when you adjust the resistance, the magnets move closer or farther from the flywheel which increases or decreases the workout load.

The bike makes available only 7 resistance levels. However, as we’ve mentioned above, since the flywheel is heavy, even the lowest resistance level delivers a pretty consistent pedaling difficulty. Conversely, the top resistance level simulates a steep climb which should be quite a challenge even for the most seasoned users.

Of course, the magnetic brake system comes with several advantages over a friction resistance system. For example, the brake does not touch the flywheel. Therefore, the pedaling motion is very smooth. Also, since there is no friction between the brake and the flywheel, the brake doesn’t wear out, and the usage of the bike is very quiet.

Fitness monitor

The bike comes with a fairly decent fitness monitor. It features an LCD display (without LED backlight) divided into four distinct windows. The top one covers the Race program. The 2nd window covers speed and cadence. The 3rd window shows distance and watts, and the bottom window covers time and pulse.

The speed and distance are shown in imperial units. There is no option for selecting metric units. For pulse reading you have to use the integrated sensors; the meter is not telemetric, and therefore, it cannot read your pulse through a wireless chest strap transmitter.

The fitness monitor allows you to set goals for time, distance, calories, and for the race program. When a goal is set for time, distance, and calories, the display will show the remaining value towards that goal.

The Race program also allows you to set a goal for your Cadence. This is displayed by a segmented bar and your current Cadence is shown right under it. If you pedal slower, the Cadence bar will fall under the selected Cadence target so you’ll know that you have to pedal faster. Conversely, if the Cadence bar exceeds the target Cadence, you should pedal slower.

The monitor unit uses two AAA batteries as its power source. These are included with the bike. It starts up when you press the Mode button or when you begin pedaling. It also has a self-shutdown function which initiates if the sensor does not detect any input on the bike.

Assembly and Maintenance

The main body of the bike with all the drive and resistance elements comes already assembled. However, there still are several parts that require user assembly. You will have to attach the two base stabilizers, the saddle, the pedals, the handlebar post, the handlebars, and the fitness monitor. This shouldn’t take more than an hour. The manual provides clear assembly instructions and all the tools for the task are included.

Once the bike is assembled, maintenance doesn’t require much. All you have to do is keep it clean and periodically check for loose parts. The internal parts shouldn’t need any lubrication or maintenance for a long period of time.

The Pros

  • Durable steel frame – can hold users up to 350 lbs;
  • Aesthetic design;
  • Adjustable levelers on both bases;
  • Transport wheels on the front base;
  • 4-way adjustable seat;
  • Cushioned and contoured saddle with a median groove;
  • Multi-grip handlebar;
  • Pulse sensors integrated into the handlebar;
  • Perimeter-weighted, 40 lbs flywheel;
  • Heavy-duty crank made for standing up spin workouts;
  • Metallic alloy, dual-sided pedals, with toe cages on one side, and SPD clips for spin shoes on the other;
  • Frictionless, wear-free, magnetic resistance with 7 levels;
  • Smooth and quiet belt drive, great for apartment use;
  • Fitness monitor included – it tracks time, distance, speed, cadence, calories, and pulse;
  • Goal settings for time, distance, and calories;
  • Race program;
  • Bottle holder included;
  • Dumbbell holder included;
  • Device holder included;
  • Easy to assemble;
  • Little maintenance required;
  • Excellent warranty.

The Cons

  • No online connectivity;
  • The fitness monitor doesn’t have backlight.


The Sunny Health & Fitness SF-B1852 is a heavy-duty indoor cycling bike made for home use. It features a manual magnetic resistance system, a 40-lb flywheel, a 4-way adjustable seat, and a multi-grip handlebar. It also includes a fitness monitor that tracks time, distance, speed, cadence, calories, and pulse. In all, it’s a pretty solid bike, great for spin workouts, stamina development, strength development, interval training, muscle toning, and weight loss.

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