Sunny Health & Fitness SF-B1805 Indoor Cycling Bike

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Sunny SF-B1805

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300 lbs44 lbsManual
Frame: 3 years
Parts: 90 days

The Sunny SF-B1805 is one of the indoor cycling bikes released by Sunny Health & Fitness in 2018. Although it’s not a bike sold as a commercial model such as the ASUNA Minotaur 7150, it definitely has a construction that is similar in sturdiness with many other light-commercial indoor cycling bikes. Also, as opposed to other Sunny models, this one is equipped with a magnetic resistance system.

Technical Details and Specifications

  • Assembled dimensions: 48L x 23W x 45H inches (122L x 58W x 114H cm)
  • Assembled weight: 125.7 lbs (57 kg)
  • Flywheel weight: 44 lbs (20 kg)
  • Supported weight: 300 lbs (136 kg)
  • Handlebars: 4-way adjustable
  • Seat: 4-way adjustable
  • Pedals: With toe cages
  • Drive: Belt
  • Resistance: Manual magnetic
  • Fitness meter: Not included
  • Accessories: Bottle holder, tablet holder
  • Warranty: Frame 3 years, Parts 90 days


The Sunny Health & Fitness SF-B1805 features a heavy-duty frame designed to support any type of spin workout. Most of it is made of thick steel tubing which results in an impressive overall weight. With the frame fully assembled, the bike weighs approx. 125 lbs (57 kg), which is more than three times the weight of a mountain bike. This weight, puls your own weight results in a very high stability. Therefore, no matter what workouts you have in mind, the bike won’t wobble or rock when you execute them.

Since it’s an exercise bike designed for spin workouts, it is equipped with a stepping pad element between the main bar of the frame and the tube of the seat. This stepping pad offers the possibility to perform spin workouts that require you to dismount, step-up and step-down of the frame repeatedly, in order to engage more muscles. It’s also rubberized to prevent damage to the paint finish and provide a better grip of your shoe on it.

Speaking of the paint finish, the Sunny SF-B1805 features a durable powder coating which is resistant to rust and abrasion. The color uses for the main frame is black, with the Sunny logo painted red. However, the adjustment posts and sliders of the seat and handlebars, as well as the flywheel feature a chrome plating.

The bike isn’t extremely large compared to other fitness equipment such as treadmills or front-drive ellipticals. With the frame fully set up, it is approx. 48″ (122 cm) long, and 23″ (58 cm) wide. It is recommended, though, to leave at least two feet of clearance all around it, to be able to perform all the spin workouts correctly and access the bike with ease.

The base stabilizers are equipped with adjustable levelers. Each leveler has a rubberized pad as well. Therefore, you can perfectly level it on any type of floor. Also, due to the rubberized pads, the bike has a good grip on the floor and won’t slide sideways or back and forth during your workouts. Plus, there is no need to place it on a rubberized mat.

Despite its rather heavy construction, the bike shouldn’t be too difficult to move once it is assembled. Its front base has two large silicone wheels which considerably facilitate its transport.

Seat & handlebars

The Sunny Health & Fitness SF-B1805 indoor cycling trainer is equipped with a high-comfort seat. It’s 8″ (20 cm) wide, and 10″ (25.4 cm) long offering plenty of contact surface. It integrates approx. 2″ (5 cm) of foam cushioning and has shock absorption springs at the rear. It also has a longitudinal groove for a superior airflow under the user and a healthy blood circulation. In all, it’s definitely superior to the average slim spin bike seat, at least in terms of comfort.

The seat is 4-way adjustable. Its upright post along with its horizontal slider is designed to accommodate users with an inseam between 28″ and 38″ (71 – 96 cm), in other words, users between 5’0″ and 6’5″ (153 – 196 cm). Its upright bar offers multiple adjustment positions, while the seat slider also provides several inches of front to back adjustment.

The bike is equipped with a multi-grip handlebar, quite similar to the handlebar of the L NOW Pro C580. It has two long aero bars in the middle which offer the possibility of a racing grip. There is a tablet holder or reading rack attached to the aero bars, a feature that many other bikes do not have. The whole handlebar assembly is urethane-dipped in order to provide a secure and comfortable grip. Just as the seat, the handlebar is 4-way adjustable.

Resistance system

The Sunny SF-B1805 is equipped with a manual magnetic resistance system, similar to the BodyCraft SPT bike. Its magnetic brake hugs the top section of the flywheel. It is attached to the tension knob on the top of the main bar of the frame. As you turn the knob clockwise, the brake will cover a larger portion of the flywheel which results in a higher intensity of the magnetic field. This ultimately leads to a higher pedaling difficulty.

Since the resistance system is manual, the bike doesn’t need to be connected to a power source. Also, there is no contact between the brake and the flywheel so the pedaling remains smooth and whisper-quiet, without any friction or wear and tear.

As opposed to other spin bikes that have a magnetic resistance system, this one doesn’t have pre-determined resistance levels. You can basically turn the tension knob until the resistance feels adequate to the workout that you want to execute. The highest tension setting does provide quite high difficult, offering the possibility to train on a superior level and achieve a consistent muscle burn.

Last but not least, the unit’s tension knob also has the function of an emergency brake. You can press it down to immediately stop the flywheel from spinning. This is quite important in case you pedal at a very high speed as it’s very risky to try to stop the flywheel by abruptly ceasing your pedaling. This may lead to injuries as the flywheel is quite heavy.

Drive system

One of the main elements to cover here is the flywheel. This Sunny exercise bike is equipped with a 44 lbs (20 kg) flywheel which is perimeter-weighted. This type of construction leads to a highly aggressive inertia but also delivers a very smooth and steady pedaling motion.

Needless to say, the flywheel and the bike’s transmission allow pedaling in reverse. However, when pedaling in reverse you will benefit from the same resistance as for pedaling normally. Also, coasting is not possible on this bike.

Since it’s a magnetic resistance exercise bike, it uses a belt for its transmission, not a chain. A belt drive comes with several advantages. For example, you don’t have to lubricate it. It generates less vibration than a chain. And the pedaling motion is very smooth, almost completely silent.

As we’ve mentioned above, this Sunny indoor cycling bike is made for spin workouts. It is equipped with a highly durable 3-piece crankset with solid steel crank arms. Therefore, as long as the user doesn’t exceed the 300 lbs (136 kg) maximum weight capacity, the bike can support any type of workout that requires standing up on the pedals.

The included pedals are made of metallic alloy. They don’t have SPD clips for spin shoes but do have toe cages in case you need extra foot stability. They also have standard threads, so you can easily find replacements for them if needed.

One last aspect to mention here is the bike’s Q-Factor (spacing between the pedals). The Sunny Health & Fitness SF-B1805 has a 177 mm (6.9″) Q-Factor, which can be classified as a medium one. This means your feet are positioned on the pedals naturally, and the pedaling motion doesn’t generate extra lateral stress on the knees and ankles. There are, though, other exercise bikes with an even smaller Q-Factor. So, in case 177 mm it too much for you, two other models that you can check out are the ASUNA Sprinter 6100, or the Spinner L7.

Assembly & Maintenance

The bike’s main drive and resistance elements come already attached to the core frame. So, when it comes to assembly, you only have to attach the two base bars, the seat post, the handlebar post, the seat, the handlebar and the pedals. This shouldn’t take longer than 30-40 minutes. The manual provides detailed assembly instructions and schematics. Also, all the tools needed for the assembly are included.

Maintenance doesn’t require much. As we’ve mentioned above, the bike’s transmission doesn’t require lubrication. So, basically, all you have to do is run a periodic check for loose or damaged bolts and parts.

The Pros

  • Sturdy steel construction – can support users up to 300 lbs;
  • Transport wheels included;
  • Adjustable levelers with rubber pads on all bases;
  • Rubberized stepping pad element;
  • Durable metallic pedals with toe cages;
  • Cushioned seat with suspension springs at the rear;
  • 4-way adjustable seat;
  • 4-way adjustable handlebars;
  • Smooth and quiet belt drive;
  • Heavy, 44 lbs inertia-enhanced flywheel;
  • Frictionless magnetic resistance;
  • Bottle holder included;
  • Tablet holder included;
  • Little maintenance required;
  • Really easy to assemble;
  • Decent warranty.

The Cons

  • No exercise meter;
  • No water bottle.


The Sunny Health & Fitness SF-B1805 is an indoor cycling bike designed for spin workouts. It’s equipped with a magnetic resistance system, a heavy flywheel, and a quiet belt drive. It offers superior micro-adjustability; both its seat and handlebars are 4-way adjustable. It’s a heavy-duty bike, perfect for high-intensity cardio workouts, interval training, muscle toning, strength and stamina development, and weight loss. And finally, even though it doesn’t come with an exercise meter, this Sunny exercise bike definitely offers an excellent value for the price.

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6 thoughts on “Sunny Health & Fitness SF-B1805 Indoor Cycling Bike”

  1. I am stuck deciding between this bike and the Efitment Ic033- any thoughts? Right now Efitment can be purchased for $380 off their site and this bike is $572 on Amazon

    1. Well, despite the fact that the Efitment IC033 has a workout computer and is a fairly decent bike, the Sunny SF-B1805 seems more solid and has better overall user reviews. I’d go with the Sunny.

    1. The SF-B1805 has front-to-back adjustability for the handlebar as well as vertical adjustability; the handlebar of the SF-B1711 only adjusts up/down.
      Also, the SF-B1805 has a different magnetic brake construction. The brake “hugs” the flywheel so the resistance is slightly superior.

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