Sunny Health & Fitness SF-RB4905 Recumbent Bike

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Sunny SF-RB4905

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242 lbsManual
8 levels
Frame: 3 years
Parts: 180 days

The Sunny SF-RB4905 is one of the recumbent bikes released by Sunny Health & Fitness in 2020. It’s an affordable exercise bike made for home use. In terms of features, it can be compared with the Efitment RB034, or with the Sunny SF-RB4953, but has a lower weight capacity and lacks the Recovery function.

Key Features and Specifications

  • Assembled dimensions: 56L x 25W x 41H inches (142L x 63W x 104H cm)
  • Assembled weight: 57.7 lbs (26 kg)
  • Weight capacity: 242 lbs (110 kg)
  • Seat: Adjustable
  • Resistance: Magnetic, 8 levels
  • Performance monitor: Time, distance, speed, calories, pulse, goals, scan
  • Extras: Device holder
  • Warranty: Frame 3 years / Parts 180 days

Frame construction

The Sunny Health & Fitness SF-RB4905 recumbent exercise bike features a steel frame with pretty sturdy construction. Its seat assembly is rated for a maximum user weight capacity of 242 lbs (110 kg) which is not bad for a home-use machine. Its frame combines rectangular, cylindrical, and oval steel tubing while the covers of the drive system are made of durable thermoplastic material.

All the steel bars in the bike’s construction are coated with a corrosion-resistant and chip-resistant paint finish. The color used is light gray, this being the only color available for this Sunny exercise bike.

The bike is not extremely large but does take approx. 56″L x 25″W (142 x 63 cm) of floor space. Plus, it is recommended to leave at least two feet of clearance all around it for ease of access. This being said, it may not fit too well in a small room. Also, the bike is not foldable and cannot be stored vertically.

This Sunny exercise bike is not too heavy either. With all the parts assembled, its net weight is only 57.7 lbs (26 kg). This being said, it can be carried and assembled by only one person. Plus, once it is assembled, it can easily be moved as its front base is equipped with two small transport wheels. Its rear stabilizer features two rotating polygonal caps which can serve as floor levelers.

The bike has a step-through design. Not all recumbent bikes have this feature, so it can be quite a plus for users with certain disabilities as it considerably eases the entry and exit.

Seat and handlebars

The Sunny SF-RB4905 recumbent bike is equipped with a large seat designed for superior comfort. To begin with, the seat pad is fairly large, approx. 15″ (38 cm) wide, and 11″ (28 cm) long so it provides plenty of contact surface. Both the seat pad and the backrest pad integrate a thick layer of foam cushioning with a durable vinyl cover.

The seat is two-way adjustable (front, back). It is attached to a durable rail system that offers superior stability for it. Its adjustment system uses a lever which means that you don’t have to stand up to adjust its position. The backrest is non-adjustable, though. It does not have a reclining feature and you cannot adjust its height independently from the rest of the seat. It attaches to the backbone of the seat frame via two screws.

The seat adjustment span is 8″ (20 cm). The applicable inseam length for this Sunny exercise bike is 30″ – 38″ (76 – 96 cm). Therefore, the bike should be able to accommodate users between 5’2″ and 6’4″ (157 – 193 cm) allowing a complete leg extension. Also, as we’ve mentioned above, it is rated for a maximum user weight limit of 242 lbs (110 kg).

The bike is equipped with two sets of handlebars. One attaches to the seat assembly, the other is directly welded to the front mast of the bike. The seat handlebars integrate stainless steel pulse sensors and have longer, curved-up grips for improved comfort. The front handlebar has shorter grips slightly bent towards the user. They do not have pulse sensors. Both handlebar sets feature high-density foam sleeves for an improved grip. None of them are adjustable.

Drive and resistance

The Sunny Health & Fitness SF-RB4905 recumbent bike integrates a fairly large flywheel. It weighs 6.6 lbs (3 kg) and has a perimeter-weighted design. This improves inertia adding stability and smoothness to the ride.

The flywheel is bi-directional. In other words, you can pedal in reverse on this bike. However, coasting is not possible. The pedals continue to spin for as long as the flywheel is spinning.

The bike is equipped with a belt drive system. It uses a 370PJ6 poly-v rubber belt resistant to stretching and abrasion. Since it’s a belt drive, not a chain, it does not require any lubrication. It also contributes to the overall smooth and quiet pedaling motion.

The Sunny SF-RB4905 recumbent bike is equipped with a standard manual magnetic resistance system. This means that you don’t need a power adapter for it, and you don’t need to connect it to a power outlet. But it also means that the bike cannot automatically adjust the resistance and does not have pre-set workout programs.

The main resistance element is an internal magnetic brake connected to the tension knob on the bike’s front mast through a steel cable. When you turn this knob clockwise, the brake moves closer to the flywheel which increases the pedaling difficulty.

The bike offers 8 distinct tension settings. As a general idea, the first level of resistance is fairly light, providing little pedaling difficulty. The 7-8 levels aren’t extreme either but do provide considerably more tension. This being said, the bike is made for light to medium-intensity workouts.

The bike’s crankset is fairly sturdy, but since this is a recumbent bike and not a spin bike, it is not meant for standing up on the pedals. The crank arms are cylindrical made of solid steel with a chrome finish. The pedals are made from durable thermoplastic material. They have weight elements in order to always turn face-up when you remove your feet from them. They are also equipped with adjustable straps so you can perfectly secure your feet into position.

Performance monitor

The performance monitor included with the Sunny Health & Fitness SF-RB4905 is the same model as the one supplied with the Sunny SF-RB4876. It’s a monitor without online connectivity or pre-set programs. It features an LCD display (without LED backlight) that tracks time, distance, total distance, speed, calories, and pulse. Speed and distance are shown in English units (mph and miles); there is no option for metric units. Also, the pulse reading function is grip contact only. The monitor unit can only read your pulse if you hold on to the sensors integrated into the seat handlebars. It cannot read your pulse from a wireless heart rate chest strap.

The performance monitor unit is battery-powered. It requires 2 AAA batteries which are included. It starts recording distance, calories, etc. when you begin pedaling and also turns off automatically if it does not detect any activity on the bike for more than four minutes.

The monitor unit features three buttons – Mode, Set, and Reset. The Mode button allows you to select the workout value that you want to view on the display, or to select the Scan Mode which rotates all the metrics showing each one for 6 seconds. The Set button offers the possibility to select goals for time, distance, and calories burned. If a goal is selected, the unit counts down from the selected value until it reaches zero. The Reset button clears all the values to zero, except the odometer (total distance) value which can only be reset if you remove the batteries from the unit.

Two last notable features to mention here are the device holder and the heart rate zone sticker. The device holder consists of a small shelf above the unit’s display. It is large enough to accommodate any tablet or smartphone. The heart rate sticker is a nice touch, great to have close by if you want to keep in a certain BPM zone without consulting the manual.

Assembly and Maintenance

The bike’s base frame with the drive and resistance unit comes pre-assembled. You only have to add the two base stabilizers, the pedals, the seat, the front mast, and the performance monitor. This shouldn’t take more than an hour. The manual provides clear assembly instructions and illustrations and all the necessary tools are included.

Maintenance doesn’t require much. You only have to keep the bike clean, wipe off the sweat that might fall onto the frame or monitor at the end of the workout, and periodically inspect the bike to make sure it still functions properly. The internal parts do not require lubrication.

The Pros

  • Sturdy, steel frame – 242 lbs capacity
  • Adjustable levelers on the rear stabilizer;
  • Transport wheels on the front stabilizer;
  • Step-through frame design for easy access to the seat;
  • Seat handlebars with pulse sensors;
  • Front handlebars included;
  • Padded seat and backrest, for optimal comfort;
  • Lever-based seat adjustment system;
  • Quiet magnetic resistance system;
  • 8 levels of magnetic resistance;
  • Weighted pedals with adjustable straps;
  • Exercise meter that can track time, distance, total distance, speed, calories, and pulse;
  • Goal setting functions for time, distance, and calories;
  • Device holder included;
  • Lightweight, easy to handle;
  • Fairly easy to assemble;
  • Little to no maintenance required.

The Cons

  • No bottle holder;
  • No LED backlight on the display of the performance monitor.


The Sunny SF-RB4905 is a recumbent exercise bike made for home use. It is equipped with a manual magnetic resistance system, a comfortable seat with lever adjustment, and a performance monitor that tracks time, distance, speed, calories, and pulse. It’s a great bike for light to medium-intensity cardio training, recovery training, weight loss, muscle toning, and stamina development.

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