Sunny SF-RB4708 Recumbent Bike


The Sunny SF-RB4708 Recumbent Bike is one of the newest exercise bikes from Sunny Health & Fitness. It has movable handlebars that connect to a frame at the front base which allows for an upper-body workout. The handlebars move at the same time that the pedals spin because they are interconnected.

The handlebars and the pedals are a very crucial part of any indoor exercise bike because they are responsible for comfort and suitability. The recumbent bike is one of the most comfortable indoor exercise bikes because of its design and the seat in particular.

The SF-RB4708 has a magnetic resistance system. There are eight levels of resistance, which is excellent for beginners and medium fitness level individuals. Great for seniors and folks recovering from an injury or other forms of a medical condition that requires physical therapy.  Also, it is a belt-driven bike that has the characteristics of smoothness and quietness.

The Sunny SF-RB4708 comes with a primary console. The monitor displays workout data such as the time, distance, speed, odometer, and calories burned. It also shows heart rate data due to the EKG sensors that integrate onto the handlebars.

Learn more in my complete review below

Sunny SF-RB4708 Recumbent Bike
Sunny SF-RB4708 Recumbent Bike

Product: Sunny SF-RB4708 Recumbent Bike

Price: For a great deal on this bike, merely go here on Amazon

Warranty: Frame 3 years / Parts 90 days

My rating: 8.25/10

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

SF-RB4708 Frame construction

The Sunny SF-RB4708 recumbent bike features a frame made of steel tubing. The base longitudinal bar is a single piece. This results in a superior overall sturdiness. The front and rear base bars attach to the mainframe, though, via bolts.

The front base integrates transport wheels, while the rear base features adjustable stabilizers. The middle of the bottom frame bar also has a small stabilizer which improves the bike’s overall stability. Also, the assembled machine weighs approx. 91 lbs (41 kg), so its balance shouldn’t be an issue.

Although the Sunny SF-RB4708 recumbent bike isn’t a large fitness machine such as a commercial elliptical or a treadmill, it still takes quite a bit of floor space. With the frame fully assembled, it is 60″ (153 cm) long, and 25.5″ (65 cm) wide.

It requires at least two feet of clearance all around on the sides and at least one foot of room at the front and rear for unhindered operation. Therefore, it may not fit well in a small room.

All the steel parts in the frame construction are coated with corrosion-resistant paint, grey in color, this being the only color available for this exercise bike. But even though its frame coating is corrosion-resistant, the bike is for indoor use only. If storing it or using it outside, moisture can eventually damage its internal parts, or the screws and bolts may catch rust.

Sunny SF-RB4708 Recumbent Bike

Finally, the bike’s frame is well-constructed; it can withstand users up to 350 lbs (159 kg). The bars of the seat base is square, not cylindrical as the handlebars and the other front frame bars, an aspect which increases its overall sturdiness.

Seat and handlebars

The Sunny Health & Fitness SF-RB4708 is equipped with a comfortable, contoured seat, featuring a durable synthetic upholstery. Both the seat and the backrest integrate a relatively thick layer of padding. The whole seat assembly is adjustable, connecting to an oblique rail, which offers an adjustment span between 26.5″ and 34″ (67 – 86 cm).

Also, the distance between the seat and the closest hand-grip to the seat varies between 12″ and 36″ (30.5 – 91.5 cm). Thus, the bike can accommodate users between 5’0″ and 6’5″ (153 – 195 cm) with no problem.

The backrest does not recline, nor does it adjust in any way, independently from the seat. It is attached directly to the same seat bar and will move along with the seat on the adjustment rail.

As I’ve mentioned above, this exercise bike features moving handlebars only. They cannot be locked in place and will continue to run for as long as the pedals are moving. However, in case you want to exercise using only the arms, you can place your feet on the floor.

SF-RB4708 Drive and resistance

The Sunny SF-RB4708 features a manual magnetic resistance system. It consists of a magnetic pad connected via a steel wire, to the lever on the front frame bar. By moving the lever up and down, you increase or decrease resistance.

There are eight resistance settings available. The highest resistance levels (7-8) are not too hard, though. Differently put, this exercise bike delivers a light to medium workout, being an adequate choice for users who require recovery training or elderly users.

Sunny SF-RB4708 Recumbent Bike
Sunny SF-RB4708 Recumbent Bike

When it comes to the bike’s drive system, just as most other models with a manual magnetic resistance system, this particular one features a belt drive. It uses a stretch-resistant, heavy-duty belt, designed to last for many years of use. Since it’s a belt-drive, it doesn’t require any lubrication. The bike’s operation is also very smooth and quiet.

The integrated flywheel is not extremely heavy. Its weight is not specified, but for bikes, in this range, it usually weighs between 8 and 12 lbs. It’s perimeter-weighted, though, which means it delivers a smooth motion.

Since it’s a recumbent bike, the crankset is not for spin workouts. Differently put, you will probably break it if you try to pedal while standing up on the pedals. However, it’s equipped with a sturdy crankset, featuring solid steel crank arms.

The pedals supplied with the bike are a durable nylon material; they feature a weighted design and integrate adjustable straps for maximum foot stability. They also have standard threads, so it’s easy to find replacements for them if needed.

This recumbent bike features a narrow Q-Factor, which means the foot positioning onto the pedals is comfortable, without any lateral stress on your knees.


The Sunny Health and Fitness SF-RB4708 recumbent bike come with a pretty basic console. It can track your pulse along with time, distance, speed, and calories. It has an odometer function, and it allows you to set up targets for time, distance, calories, and pulse.

It can only track your pulse via the EKG sensors integrated into the handlebars. However, it is not telemetric; therefore, it does not work with Polar or other wireless HR chest strap transmitters.

The meter is easy to operate. To begin with, it has a SCAN function which rotates the workout metrics showing each one on display for 6 seconds.

You can toggle the SCAN function OFF, by pressing the MODE button, to keep only the parameter that interests you to view at all time. The SET button allows you to set a value for time, calories, distance, and pulse, while RESET clears all the metrics to zero.

Sunny SF-RB4708 Recumbent Bike

The unit has a sleep mode function to which will enter after 4 minutes of inactivity. It will turn back on when you begin pedaling or press any of the buttons. It’s battery-powered and requires 2 AA batteries which (are included).

The console unit is attached to a bar that allows angle adjustment. It also integrates a tablet holder, which can accommodate any tablet.

SF-RB4708 Assembly and Maintenance

The core of the bike is pre-assembled and attached to the mainframe. Therefore, you only have to connect the front and rear base bars, the seat’s adjustment rail, the seat, the pedals, the moving arms, and the console. This may take up to an hour.

However, the included manual provides all the necessary assembly instructions. Also, all the tools required for the assembly (are included).

Since the bike features a magnetic resistance system, there isn’t any maintenance required for the internal parts. So, the only thing to do for this matter is to check for loose bolts and parts periodically.

Technical Details and Specifications

  • Assembled dimensions: 60L x 25.5W x 52H inches (153L x 65W x 132H cm)
  • Assembled weight: 91 lbs (41 kg)
  • Weight capacity: 350 lbs (159 kg)
  • Seat: Adjustable
  • Pedals: With adjustable straps
  • Resistance: Magnetic, eight levels
  • Console: Time, distance, speed, calories, odometer, pulse, SCAN
  • Warranty: Frame 3 years / Parts 90 days

    Sunny SF-RB4708 Recumbent Bike
    Sunny SF-RB4708 Recumbent Bike


  • Solid frame for a light recumbent bike, with a maximum user capacity of 350 lbs;
  • Comes with adjustable stabilizers on the rear base;
  • Transport wheels on the front base;
  • Step-thru frame design;
  • Mobile handlebars;
  • EKG sensors in each hand-grip;
  • Adjustable seat – can accommodate users between 5’0″ – 6’5″;
  • Cushioned seat and backrest, for maximum comfort;
  • Quiet magnetic resistance system;
  • Adjustable resistance (8 levels);
  • Weighted pedals with adjustable straps and standard threads;
  • A console that can track time, distance, total distance, speed, calories, and pulse;
  • Target settings for time, distance, calories, and pulse;
  • Tablet holder included;
  • Console mast is angle-adjustable;
  • Easy to assemble and operate;
  • Transport wheels and rear stabilizers;
  • Little to no maintenance required.


  • No bottle holder;
  • No recumbent handlebars (or armrests) at the seat;
  • The console isn’t backlit.

Sunny SF-RB4708 Summary

The Sunny SF-RB4708 is a heavy-duty recumbent bike for home use. It features a solid steel frame which can support users up to 350 lbs, with moving handlebars, a comfortable seat and a console with target settings for pulse, calories, distance and time.

It’s an exercise bike for users of all levels, great for light to medium intensity workouts, stamina development, recovery training, and weight loss. You can burn up to 5-600 calories per hour on it, depending on the resistance levels used. And finally, it’s not an expensive exercise bike, offering excellent value for the price.

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

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3G Cardio Elite RB Recumbent Bike

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