Sunny Synergy Indoor Cycling Bike | Provides a Vigorous Workout

Jumpstart your in-home fitness routine with the Sunny Synergy Indoor Cycling Bike SF-B1879  by Sunny Health & Fitness. Indoor cycling can strengthen cardiovascular health and engage your core, arms, and lower body with proper and consistent exercise.

Synergy’s 30 lb flywheel is for intense and vigorous workout sessions. Heavier flywheels maintain continuous momentum more effectively, resulting in a smooth and efficient ride. In addition, this home-use bike has a durable belt-drive mechanism that is smooth, consistent, and quiet, allowing you to focus more on your performance while cycling.

Build new workouts using the battery-powered fitness monitor when you effectively track your progress. Quickly check your speed, distance, time, RPM, pulse, and calories burned at a glance while you cycle. Monitor your cardiovascular performance with the built-in HR pulse-sensing grips to actively check your workout efficiency displayed on the fitness monitor.

Learn more in my complete review below!

Sunny Synergy Indoor Cycling Bike SF-B1879
Sunny Synergy Indoor Cycling Bike SF-B1879

Product: Sunny Synergy Indoor Cycling Bike SF-B1879

Price: For a great deal on this bike, merely go here to Sunny Health &

Warranty: Frame 3 years / Parts 180 days

My rating: is 9/10

Affiliate Disclosure: As a Sunny Health & Fitness Affiliate Program participant, I earn commissions on purchases made through links in the post. Full disclosure

Details and Specifications

  • Assembled dimensions: 49L x 22W x 50.5H inches (124L x 56W x 128H cm)
  • Assembled weight: 88.2 lbs (40 kg)
  • Flywheel weight: 30 lbs (13.6 kg)
  • Weight capacity: 275 lbs (125 kg)
  • Seat: 4-way adjustable
  • Drive: Belt
  • Resistance: Manual magnetic
  • Fitness Monitor: Time, distance, total distance, speed, RPM, calories, pulse, scan
  • Extras: Bottle holder, device holder, dumbbells holder
  • Warranty: Frame 3 years / Parts 180 days

SF-B1879 Frame Construction

The Sunny Health & Fitness Synergy indoor cycling bike features a heavy-duty triangular frame of steel tubing. It combines oval and rectangular bars in its construction for improved aesthetics. Their joints are precision-welded, and the seat bar goes all the way to the median base bar, welded to it for enhanced overall sturdiness. The only major non-metallic part of the bike’s construction is the durable thermoplastic material’s drivetrain guard.

Sunny Synergy Indoor Cycling Bike SF-B1879

The bike’s frame also integrates a step-up bar, the small horizontal tube that connects the seat tube with the main oblique tube. Therefore, a shorter user with mounting and dismounting is a support point for stretching or various spin workouts requiring you to mount and dismount repeatedly. Not all spin bikes have this feature, so it is a plus.

The bike is a few inches larger than other models, but it doesn’t take up too much space like most other spin bikes. It is approx. 49″ (124 cm) long and 22″ (56 cm) wide, while its highest point is at approx. 50.5″ (128 cm) above floor level when the handlebar extends out. However, it is advisable to allow at least two feet of clearance all around it to ease access.

The fully assembled bike is relatively heavy. Its net weight is approx—88.2 lbs (40 kg). Therefore, two people should carry the packaged unit. However, once assembled, it can easily be moved by only one person as its front base bar has a set of small wheels. Also, it’s important to mention that both base stabilizers have adjustable levelers.

All the steel tubes in the bike’s frame construction come with a corrosion-resistant paint finish. The primary color used is gray. The only exceptions are the seat and handlebar posts, which are black, while the flywheel is chrome-plated.

Seat and handlebars

The Sunny Synergy indoor cycling bike includes a high-comfort saddle. It is wider than the average spin seat and integrates a foam cushioning layer. It also has a long median groove for extra breathability.

It’s important to note that the saddle has a standard, collar-type attachment system. Thus, you can slightly tilt it forward or backward. It also means that it is replaceable, if necessary, and compatible replacements should be available in most bike shops.

Sunny Synergy Indoor Cycling Bike SF-B1879
Sunny Synergy Indoor Cycling Bike SF-B1879

The bike’s seat is four-way adjustable (front, back, up, down). It features two large knobs, easy to grip and turn. Its vertical post has several adjustment positions and offers approximately an adjustment span. 10″ (25.4 cm), between 27″ (68.5 cm) and 37.5″ (95.2 cm) above floor level. The bike’s horizontal slider also offers 4.5″ (11.4 cm) front-to-back adjustment.

Therefore, the bike comfortably accommodates users between 5’0″ and 6’5″ (153 – 196 cm) with no problem, allowing a complete range of motion. It also has a maximum user weight limit of 275 lbs (125 kg), which applies to the seat.

The Sunny Synergy SF-B1879 exercise bike features a multi-grip handlebar. It offers the possibility to adopt a standard grip, a racing grip, a climbing grip, and an aero grip. However, unlike the seat, it is only two-way adjustable. In addition, it does not have a horizontal slider.

A layer of high-density foam material covers the bike’s handlebar to provide a comfortable and secure grip. Its side grips integrate metallic pulse sensors, and the included fitness monitor has a pulse-tracking function. The aero bar’s base section features a small ABS cover as a phone or tablet holder.

SF-B1879 Resistance system

The Sunny Synergy indoor cycling bike has a manual magnetic resistance system. A magnetic brake is attached to the tension knob on the frame’s top tube.

As you turn the knob clockwise, the magnetic brake moves closer to the flywheel, increasing the magnetic drag and the pedaling difficulty. The knob is an emergency brake, and when pressed down, it stops the flywheel from spinning.

Since the bike’s braking system is manual, it does not require an adapter or an external power source. But on the other hand, it does not adjust the resistance automatically. Also, the included performance monitor does not have pre-set programs.

Sunny Synergy Indoor Cycling Bike SF-B1879

Although the bike has a magnetic brake, it does not have pre-determined steps or levels. Instead, you tighten it until you get the desired pedaling difficulty. The main advantage of a magnetic brake is that the brake pad does not touch the flywheel, and the pedaling motion is very smooth and quiet.

Drive system

The bike comes equipped with a heavy-duty 3-piece crankset similar to a mountain bike crankset. In addition, it features solid steel crank arms and metallic pedals. Therefore, it can support the user’s whole weight if they don’t exceed the specified 275 lbs (125 kg) weight limit.

The pedals do not have SPD elements for spin shoes, but they do have adjustable toe cages if you want to secure your feet on them. Their threads are 9/16″, though. So, replacements for them are widely available.

This Sunny Health & Fitness indoor cycling bike has a 30-lbs (13.6 kg) chrome-plated flywheel featuring ABS side covers. It is perimeter-weighted for improved inertia.

It also reverses pedaling, but you cannot coast on the bike due to the simple drivetrain construction. When pedaling in reverse, you will get the same resistance as when pedaling forward.

The bike comes equipped with a belt drive system. It uses a heavy-duty poly-v rubber belt. This type of drive system comes with a few advantages. For example, as opposed to a chain drive, you don’t have to lubricate it. Also, it contributes to the overall quietness and smoothness of the ride.

Fitness monitor

The Sunny Synergy indoor cycling bike includes a fitness monitor. It features an LCD (without LED backlight) that tracks time, distance, total distance, speed, RPM, calories; and pulUnfortunately, the speed and distance are in MPH and miles; there is no option for setting them to km/h and kilometers.

Sunny Synergy Indoor Cycling Bike SF-B1879
Sunny Synergy Indoor Cycling Bike SF-B1879

Also, you will have to hold on to the sensors integrated into the handlebars for the pulse reading function. Unfortunately, the monitor is not telemetric, so it cannot track your pulse from an HR chest strap.

The fitness monitor is easy to use. It has only one button (MODE). You can press it repeatedly to select the workout metric you want to view or the Scan Mode, which rotates all the metrics.

The fitness monitor does not have pre-set workout programs or goal settings. However, the Mode button also has a reset function, and you can press and hold it for a few seconds to clear all the values to zero.

The monitor requires two AAA batteries as its power source. It starts when you pedal and automatically turns off after four minutes of inactivity on the bike.

SF-B1879 Assembly and Maintenance

The bike’s body comes pre-assembled, with the flywheel, drivetrain, brake, and crankset attached. Then, you only need to add the two base stabilizers, the seat post, the saddle, the handlebar post, the handlebar, the pedals, and the fitness monitor.

Consequently, it shouldn’t take more than 30 minutes of your time. All the necessary tools for the task come with the bike, and the manual provides precise assembly instructions.

Since it’s a belt-drive bike, its transmission does not require lubrication. Therefore, all you have to do for maintenance is periodically check for loose bolts and parts. Also, since the bike uses a magnetic brake, you don’t have to worry about its wear and tear or replace the brake pad.


  • Heavy-duty steel frame – 275 lbs weight capacity;

    Sunny Synergy Indoor Cycling Bike SF-B1879
  • Aesthetic design;
  • Adjustable stabilizers on both bases;
  • Transport wheels included;
  • 4-way adjustable seat;
  • Cushioned saddle with a median groove for breathability;
  • Multi-grip handlebar with pulse sensors;
  • Smooth and silent belt drive;
  • Perimeter-weighted flywheel for enhanced inertia;
  • Magnetic resistance, with zero friction;
  • Fitness monitor included – it can track time, distance, total distance, speed, RPM, pulse, and calories burned;
  • The bottle holder included;
  • Device holder included;
  • The dumbbell holder included;
  • Easy to assemble;
  • Little maintenance is required.


  • No backlight on the fitness monitor LCD;
  • The pulse and calorie readings aren’t super accurate.

Sunny Synergy Indoor Cycling Bike Summary

The Sunny Synergy SF-B1879 is an indoor cycling bike made for home use. It has a manual magnetic resistance system, a 4-way adjustable seat, a 30-lb perimeter-weighted flywheel, and a fitness monitor that tracks all the essential workout metrics.

It also has a pretty sturdy construction with a weight limit of 275 lbs. Moreover, it’s a stationary bike for high-intensity spin workouts, muscle toning, stamina and strength development, interval training, and weight loss.

I hope you found this article helpful and informative. Would you please speak up if you have anything you’d like to share on the topic or any opinions about my website? I look forward to your comments, questions, and the sharing of ideas.

Please remember that you should consult your physician to determine if you have any medical or physical conditions that could risk your health and safety or prevent you from using the equipment properly. In addition, your physician’s advice is essential if you are taking medication that affects your heart rate, blood pressure, or cholesterol level.

10 thoughts on “Sunny Synergy Indoor Cycling Bike | Provides a Vigorous Workout”

  1. Haha! I do CrossFit, and yes, I can definitely attest to bikes being a very challenging and good workout. Whenever we do those in the gym, it definitely hits me very hard, and I actually consider myself a pretty athletic person. But anyway, I landed on this review because I was looking for a good bike for my mom, and I think this will work perfectly for her. Thank you so much for this review.

    • Hello Misael, thanks for your inquiry on the Sunny Synergy Indoor Cycling Bike. I hope it’s perfect for your Mom.

      Warmest regards, Robert

  2. Hiya

    This is an exciting review of the Sunny Synergy Indoor Cycling Bike | Provides a Vigorous Workout.

    It is the perfect time to start an at-home fitness workout because of the lockdowns restricting us from getting to the gym. I also like having a fitness console to effectively track my fitness metrics to know how I am progressing.

    As a crazy nutty person for fitness, I recommend this product to myself. I will bookmark this page so that I can return to it when I can purchase.

    Thank you

  3. I have a home gym in my garage (the garage has three rooms, so I use one for my exercise room). I’ve been using it much more now that Covid has been keeping me from Planet Fitness. However, I already have a Sunny Bike, and I want to say that I love it! Sunny makes durable equipment that is very user-friendly, so anyone shopping can’t go wrong with this bike.

    • Hi Alicia, thanks for stopping by. Would you please let me know if I can assist you in any way? I’d be happy to help.

      Kind regards, Robert

  4. I wouldn’t mind the pulse and calorie readings not being as accurate as other models. This one is right in the price range that I can afford. I wear a smartwatch which will give me any additional necessary information anyway, so I’m not worried about it.

    I’ll go ahead and look more into this on their site. Thanks!

  5. Thanks for a fantastic Sunny Synergy Indoor Cycling Bike review. This bike offers an intense workout. It has an excellent aesthetic design, and I like its looks. It also has a fitness console. So you can check the pulse and the number of calories burned. I haven’t seen any excise machine else with that particular feature. 

    • Hi Pasindu, thanks for stopping by and sharing your thoughts with us. Would you please let me know if I may further assist you with exercise equipment? I’m always happy to help.

      Kind regards, Robert


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