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 your cardiovascular health and engage your core, arms, and lower body with proper and consistent exercise.

The Synergy’s 30 lb flywheel is for intense and vigorous workout sessions. Heavier flywheels maintain continuous momentum more effectively and result in a smooth and efficient ride. This home-use bike has a durable belt-drive mechanism that is smooth, consistent, and quiet—which allows you to focus more on your performance while you’re cycling.

Build new workouts when you effectively track your progress by using the battery-powered display. 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 pulse-sensing grips so you can 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 on Amazon

Warranty: Frame 3 years / Parts 180 days

My rating: 9/10

Amazon Affiliate Disclosure: I may earn commissions on purchases made through links in this post.

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 console: 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 SF-B1879 indoor cycling bike features a heavy-duty triangular frame made 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 improved overall sturdiness. The only major non-metallic part in the bike’s construction is the drivetrain guard, made of durable thermoplastic material.

Sunny Synergy Indoor Cycling Bike SF-B1879

The bike’s frame also integrates a step-up bar. This is the small horizontal tube that connects the seat tube with the main oblique tube. This can help a shorter user with mounting and dismounting and serve as a support point for stretching or various spin workouts requiring you to repeatedly mount and dismount. 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 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. It is advisable, though, to allow at least two feet of clearance all around it for ease of 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 coated 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 Health & Fitness SF-B1879 indoor cycle includes a high-comfort saddle. It is a bit wider than the average spin seat and integrates a layer of foam cushioning. It also has a long median groove for extra breathability.

It’s important to mention that the saddle has a standard, collar-type attachment system. This means 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 upright post has several adjustment positions and offers an adjustment span of approx. 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) of front to back adjustment.

Therefore, the bike should be able to accommodate 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 capacity of 275 lbs (125 kg), which also 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. Unlike the seat, it is only two-way adjustable. 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 performance monitor has a pulse tracking function. The aero bar’s base section features a small ABS cover, serving as a phone or tablet holder.

SF-B1879 Resistance and drive

The Sunny Health & Fitness Synergy SF-B1879 indoor cycling trainer comes with a manual magnetic resistance system. It consists of a magnetic brake attached to the tension knob on top of the frame’s leading tube.

As you turn the knob clockwise, the magnetic brake moves closer to the flywheel, which increases the magnetic drag and the overall 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. 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.

The bike comes equipped with a heavy-duty 3-piece crankset similar to a mountain bike crankset. It features solid steel crank arms and metallic pedals. Therefore, it can support the user’s whole weight as long as 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 allows pedaling in reverse, but you cannot coast on the bike due to the simple drivetrain construction. When pedaling in reverse, you will get the same pedaling 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.


The Sunny SF-B1879 indoor cycle includes a fitness console. It features an LCD (without LED backlight) that tracks time, distance, total distance, speed, RPM, calories, and pulse. Speed and distance display 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, for the pulse reading function, you will have to hold on to the sensors integrated into the handlebars; the monitor unit is not telemetric, so it cannot track your pulse from an HR chest strap.

The fitness monitor unit 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 select the Scan Mode, which rotates all the metrics.

The console does not have pre-set workout programs or goal settings. 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 unit requires two AAA batteries as its power source. It starts when you begin to pedal and automatically turn 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 already attached. 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.

This shouldn’t take more than 30 minutes. All the necessary tools for the task come included, and the manual provides precise assembly instructions.

Since it’s a belt-drive bike, its transmission does not require any 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 about replacing 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 console 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 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 comes equipped with 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 pretty sturdy construction with a weight capacity of 275 lbs. Moreover, it’s a tremendous 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. If you have anything you would like to share or any opinions about my website, please speak up. I look forward to your comments, questions, and the sharing of ideas.

4 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


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