Sunny SF-B1877 Review: Is it the Best Cheap DYI Peloton

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By Katie Pierson, Certified Spinning® Instructor & Personal Trainer.

Is Sunny SF-B1877 Belt Drive Indoor Bike Worth-It?

If you are newer to the indoor cycling community or simply do not want to shell out thousands of dollars for a bike at home, the Sunny SF-B1877 might be just what you want. Read on to see what this bike has to offer.

Sunny Health & Fitness Magnetic Indoor Bike (SF-B1877)

In addition to the quiet ride, this model includes a battery-operated performance monitor that displays cadence, speed, distance, calories, time, and heart rate.

Amazon Reviews

Sunny Health & Fitness Bike Model Comparison

Sunny Health & Fitness has significantly impacted the indoor cycling market by offering quality cycles at a lower price. With so many great options coming from this company, knowing which model might fit your needs isn’t easy. Let’s look at the SF-B1877, SF-B1805, and SF-B1879 and how they compare.

These cycles include magnetic resistance and operate with a belt drive. This resistance and drive combination requires less maintenance and provides a tranquil riding experience. In addition, the B1877 and B1879 include a monitor that provides key metrics such as cadence, pulse, resistance, distance, and time. The monitor automatically scans through these metrics.

Sunny Health Magnetic Bike SF-B1805

Priced usually under $600, this model offers users an experience often reserved for higher-priced options. This quiet belt-driven model includes a heavier front flywheel weighing in at 44 pounds.

Amazon Reviews

Although the SF-B1805 doesn’t include a monitor, it does offer the heaviest flywheel out of these models at 44 pounds. Due to the inertia that a heavier flywheel provides, a smoother riding experience accompanies a heavier flywheel. The B1805 also boasts the highest max user weight of 300 pounds, although the other models are not far behind. Out of the three models, the B1805 is also the only one that offers 4-way adjustability to accommodate a more comprehensive height range of riders.

It is important to note that none of these models include connectivity opportunities. Still, they do have access to a selection of workouts on the Sunny website and through Sunny Health & Fitness‘s Youtube site that offers additional workouts for riders to try. Each model also includes a tablet rest.

29 pounds44 pounds30 pounds
Cadence, pulse, resistance, distance, and timeNoneCadence, pulse, resistance, distance, and time
265 pounds300 pounds275 pounds
4.5 out of 55 out of 5*5 out of 5*
* The consumer rating for B1805 and B1879 came from the manufacturer’s website compared to the Amazon rating of the B1877.

Sunny SF-B1877 Mechanics & Detailed Specs

Main Features & Specs

The Sunny SF-B1877 includes a belt-driven flywheel weighing 29 pounds in addition to magnetic resistance. This quiet model offers a Q-factor of 206mm, allowing riders to pedal more effectively at a higher pace and intensity. The sturdy frame is constructed from Alloy Steel and includes floor stabilizers so that riders can get the most out of their workout.

sunny health fitness bikes endurance belt drive magnetic indoor exercise cycle bike SF B1877 07 1800x1800

Sunny SF-B1877 Bike Specs

  • User inseam range: 27-37”
  • User weight maximum: 265 pounds
  • Resistance: Magnetic
  • Drive system: Belt
  • Flywheel Weight: 29 pounds
  • Height: 48.8”
  • Width: 20.1”
  • Length: 48.6″
  • Item weight: 82.9 pounds

Pros & Cons

Things I Loved

  • Affordable: Priced at only $319.49 with free shipping through Amazon Prime, this bike is very affordable for what it offers. 
  • Great for Beginners: This bike has everything a rider just starting out needs and nothing they do not. Besides being a great price, the straightforward design and monitor make it easy for riders to get started quickly. 
  • Quiet: If you are looking for a quiet ride, you will love that this cycle offers a belt drive. Belt drives are more peaceful than chain drives and require less maintenance. Also helping decrease the noise while riding the SF-B1877 is its magnetic resistance. Since magnets move closer and farther away from this cycle’s eco-friendly flywheel instead of coming in contact with it, this bike is silent when changing the resistance.
  • Pulse Sensors: We liked that this model offered pulse sensors located on the handlebars linked to the monitor. This is an excellent feature since this model does not provide a Bluetooth heart rate monitor option that many other bikes do on the market.

Things that could be Better

  • Light Flywheel: The flywheel is slightly lighter than what we like to see for a front flywheel placement. Heavier flywheels allow for a smoother ride.
  • Handlebar Adjustability: Unfortunately, the handlebars cannot move front and back and therefore only offer 2-way adjustability. Ideally, 4-way adjustability is the best option.

Construction & Design Quality

Constructed from alloy steel, this sturdy model offers great construction quality for its price. This bike design also provides a Q-factor of 206mm. The Q-factor is the distance between the outside of one crank arm and the other one. A smaller Q-factor allows for greater efficiency during the pedal stroke.


Unfortunately, no connectivity options are currently available with this model. However, this model does include a tablet rest so that you can follow workouts through a third-party app or website. Additionally, Sunny Health & Fitness does offer free pre-recorded classes through their Youtube channel, including cycling workouts.

Power Requirements

The SF-B1877 does not require any external power requirements to be fully operational. 


Equipped with magnetic resistance, riders can find the challenging resistance level they desire.

sunny health fitness bikes endurance belt drive magnetic indoor exercise cycle bike SF B1877 21 1800x1800


The performance monitor on this cycle tracks calories, distance, speed, time, pulse rate, and RPM. The monitor will scan through and display these metrics during the workout, but unfortunately is not backlit.

sunny health fitness bikes endurance belt drive magnetic indoor exercise cycle bike SF B1877 03 1800x1800


The pedals include toe cages making it easy to ride with your regular athletic shoes. The toe cages, of course, have an adjustable strap to make sure that your shoes are secure for your workout.

 *Remember to make sure that after you pull up on the strap to tighten it, you secure it in the bottom part of the bracket so your shoe will remain secure.

1. Sunny Synergy Pro Review
2. Best Exercise Bikes to Use with the Peloton App

Seat and Seat Cushion

The SF-B1877 offers a competitive style saddle and 4-way adjustability. Therefore, the seat moves up and down and forward and back as well. This is a must-have feature for shorter riders.

Portability & Stability

This cycle is easy to transport with the built-in wheels located at the front of the bike, which is helpful since this bike weighs over 80 pounds. The SF-B1877 dimensions are 48.8 x 20.1 x 48.56 inches. This bike also comes standard with floor stabilizers that adjust under the feet of the bike to ensure a steady ride.

sunny health fitness bikes endurance belt drive magnetic indoor exercise cycle bike SF B1877 06 1800x1800


Although the seat offers 4-way adjustability, unfortunately, the handlebars can only move forward and back. This diminished adjustability can make it harder for shorter riders to find a comfortable riding position.

Assembly and Setup

The overall consensus is that the assembly process is relatively easy, with most customers expressing they could put this cycle together in about 30 minutes. If you are not interested or are intimidated about assembling this bike on your own, an expert assembly option is available for only $89.

What Do Customer Reviews Say? 

Overall, customers were excited about the riding experience that the B1877 provides and the affordable price tag that accompanies this model. Out of almost 900 reviews on Amazon, this model was given a consumer rating of 4.5 out of 5. Many 5-star reviews include remarks like, “great entry-level bike” and “cheaper than a Peloton.” Approximately 75% of the reviews submitted on Amazon gave this bike a 5 out of 5. However, most negative reviews discussed that a loud clanking sound started within 3-6 months of regularly riding. Many expressed the noise was due to bearings that needed to be replaced. Additionally, many said that the customer service department was challenging to either get ahold of and or rectify the issue that the purchaser was experiencing.

sunny health fitness bikes endurance belt drive magnetic indoor exercise cycle bike SF B1877

Warranty and Return Policy

The Sunny SF-B1877 can be returned within 90-days of receiving it for a full refund or exchange as long as it is in its original condition. Also, a 1-year manufacturer’s warranty is included. In addition, extended warranty policies are available for purchase, including a 2-year protection plan for $24.99 on Amazon..

*Many reviewers expressed they were elated that they purchased the 2-year protection plan through Amazon since the original warranty window is short. 

The Bottom Line

Sunny Health & Fitness Magnetic Indoor Bike (SF-B1877)

In addition to the quiet ride, this model includes a battery-operated performance monitor that displays cadence, speed, distance, calories, time, and heart rate.

Amazon Reviews

The Sunny SF-B1877 is a great bike for beginner riders with its straightforward design and affordable price. If you are not wanting to spend thousands on an indoor cycling bike but are interested in an entry-level bike, this might be one to consider.

Katie Pierson CPT

Katie has been a certified fitness professional for twenty years and holds ten fitness certifications, including Spinning Elite and Personal Training. She has shared her expert knowledge in many fitness outlets like Bicycling & Verywellfit.

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