Sunny SF-RB4708 Recumbent Bike | Full Motion Arm Exerciser

The Sunny SF-RB4708 Recumbent Bike from Sunny Health & Fitness has movable handlebars connecting to a frame at the front base, allowing an upper-body workout. The handlebars move simultaneously with the pedals spinning because they are interconnected.

The handlebars and the pedals are crucial for 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 seat.

The SF-RB4708 has a magnetic resistance system. There are eight resistance levels, which are excellent for beginners and medium fitness level individuals. In addition, it is perfect for seniors and folks recovering from an injury or other medical conditions requiring physical therapy. Also, it is a belt-driven bike with smooth and quiet characteristics.

The Sunny SF-RB4708 comes with a simple fitness monitor. The monitor displays workout data such as the time, distance, speed, odometer, and calories burned. It also shows heart rate data via the hand-held EKG sensors integrated into 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 to Sunny Health &

Warranty: Frame 3 years / Parts 90 days

My rating: 8.75/10

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

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
  • Fitness Monitor: Time, distance, speed, calories, odometer, pulse, SCAN
  • Warranty: Frame 3 years / Parts 90 days

SF-RB4708 Frame Construction

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

The front base integrates transport wheels, while the rear 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 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 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 space.

All the steel parts in the frame construction come with a corrosion-resistant grey paint finish. But even though its frame coating is corrosion-resistant, the cycle is for indoor use only. If stored or used 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 up to 350 lbs (159 kg). In addition, the seat base bars are square, not cylindrical, as the handlebars and the other front frame bars, an aspect that increases its overall sturdiness.

Seat and handlebars

The Sunny Health & Fitness SF-RB4708 has a comfortable, contoured seat featuring 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 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.

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

This exercise bike features moving handlebars only. Therefore, they do not lock in place and will continue to move as long as the pedals move. However, if you want to exercise using only your 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. However, the highest resistance levels (7-8) are not too hard. For example, this exercise bike delivers a light to medium workout, which is a good 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, like most other models with a manual magnetic resistance system, this particular feature 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 it usually weighs between 8 and 12 lbs for bikes in this range. 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. You will probably break it if you try to pedal while standing up on the pedals. However, it has a sturdy crankset featuring solid steel crank arms.

The pedals supplied with the bike are made of 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.

Fitness Monitor

The Sunny Health and Fitness SF-RB4708 recumbent bike has a simple fitness monitor that tracks your pulse, time, distance, speed, and calories. In addition, it has an odometer function, allowing you to set up targets for time, distance, calories, and pulse.

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

The monitor is easy to operate. First, it has a SCAN function that rotates the workout metrics showing each 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 times. 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 monitor has a sleep mode function which will enter after 4 minutes of inactivity. It will turn back on when you begin pedaling or press any buttons. It’s battery-powered and requires 2 AA batteries, which come with the bike.

The monitor connects 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 fitness monitor.

Consequently, it may take up to an hour of your time. Furthermore, the included manual provides the necessary assembly instructions — also, all the tools required for the assembly come with the bike.

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 is periodically check for loose bolts and parts and retightening them as needed.

Please note that the smart device in the image is not included with the bike.


  • Solid frame for a light recumbent bike, with a maximum user capacity of 350 lbs;
  • It 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″;

    Sunny SF-RB4708 Recumbent Bike
    Sunny SF-RB4708 Recumbent Bike
  • Cushioned seat and backrest for maximum comfort;
  • Quiet magnetic resistance system;
  • Adjustable resistance (8 levels);
  • Weighted pedals with adjustable straps and standard threads;
  • A fitness monitor that can track time, distance, total distance, speed, calories, and pulse;
  • Target settings for time, distance, calories, and pulse;
  • Tablet holder included;
  • The fitness monitor mast is angle-adjustable;
  • Easy to assemble and operate;
  • Transport wheels and rear stabilizers;
  • Little to no maintenance is required.


  • There is no bottle holder;
  • There are no recumbent handlebars (or armrests) at the seat;
  • The fitness monitor LCD doesn’t have a backlight.

Sunny SF-RB4708 Recumbent Bike Summary

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

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

I hope you found this article helpful and informative. Would you please speak up if you have anything you’d like to share 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.

15 thoughts on “Sunny SF-RB4708 Recumbent Bike | Full Motion Arm Exerciser”

  1. Hello, I appreciate your effort in putting together this website and writing this article. Trying to stay fit is one major challenge for most people, and the time needed to go out to the gym or take a run isn’t available. So they turn to get home use devices to help stay fit. The sunny SF-RB4708 is excellent for home use, and the specifications are superb. Although I wonder if the price isn’t too much? 

    • Hello, Benny, thanks for your interest in the Sunny SRB4708. It’s not an expensive exercise bike, offering excellent value for the price.

      Happy Holidays!

  2. My grandparents have been searching for a bike to purchase that is simple in design and comfort.  This one looks like a great choice as it has eight levels to choose from as far as resistance.  Do you know how hard it is to use on the lowest level of resistance?  They are in their late 80’s and have had an exercise bike in their house for years, and they want to upgrade.  I am helping them research and find a simple yet easy to use design. This one fits this but wants to make sure it isn’t too hard to use for them.  I like that you can remove the handles to and that they work in unison with the petals for a complete workout on the bike.  Thank you for the great review


    • Hello, Douglas, thanks for your interest. The Sunny SF-RB4708 is for a light to medium workout. It would be an excellent choice for your grandparents.

      Happy Holidays!

  3. Thank you for this detailed review of the Sunny SF-RB4708 Recumbent Bike!

    My mother-in-law, now living with us, had knee surgery recently and her physical therapist and doctor both recommended a recumbent bike for her recovery.  I promptly went out and found one on Facebook Marketplace and got it for her.  Sadly, she’s pretty short and it doesn’t really adjust properly for her leg length and it’s awkward for her to use.

    I think she’s 5’4″ so I’m glad to see that it can fit people as short as 5’0″ comfortably.  I’m hoping that, if I can get her one that she can’t complain about (the lack of armrests at the seat might be a sticking point), she’ll work more towards her recovery.

    Again, thank you for this.  I’m going to have to check it out and see what she thinks of it.


  4. Hello Robert, thank you for sharing this review of the Sunny SF-RB4708 recumbent bike. When intending to purchase a recumbent bike, some things should be in mind like durability, maintainability, and smart features. This bike seems to check the boxes for those. So it offers excellent value for the price.

    All the best!

  5. I just purchased this bike for myself for my 71st birthday. It was delivered in 4 business days! It wasn’t too difficult to assemble but I’m thankful my husband could do it, with my supervision, of course. I have 2 bad knees that we’re going to be replaced this past spring but with the Covid I decided to wait. Also because of the Covid I have gained a few pounds. I’m excited to use this bike to help me get a bit more exercise. It’s real quiet so it’s great for listening to podcasts, music or watching TV. I am very happy with my purchase.

    • Hello Judi,

      Happy Birthday, I’m so happy you love the bike. I too have bad knees. I replaced the right one nine years ago. I have been holding off on my left knee until I must get it done. If I can ever be of help just reach out to me.

      All the best!


  6. I’m a 70-year-old and have exercised for years. This recumbent bike is a good value, BUT it wasn’t long after I got mine that the wheel bearings began to growl and grind. After several emails and videos, the customer service eventually agreed with me that it was, in fact, the pedal wheel bearing but said it was from what they saw (from my multiple videos) was a pedal wheel wobbling. It wasn’t wobbling, but if it were, that should have been under warranty, but now it’s past the 180 days. So I’m going to take it apart and find locally new wheel bearings. I asked for the outer and inner diameters to get them, but I haven’t been told this yet. I like the bike a lot, not happy with the service.

    • Hello Morrie, I hope you are well. I was sorry to hear about the trouble you are having with the wheel bearings. The replacement parts should be readily available at any bike shop in your area on the bright side. The pedals should be a standard 9/16th tread. I advise that you replace both pedals at the same time. As far as the manufacturer goes, I would tell them that you are replacing the pedals and expect reimbursement since the 180 day part warranty expired after you first contacted them. Please reach out to me if I can be of any further assistance.

      Warmest regards,


      • I just recently got the same recumbent bike in November. My left side just started screeching today. I am afraid to use it. I have a knee surgery coming up in may and I would like it fixed by then. Could you let me know what I am to do to fix? I dont have very much warranty left.

        Thank you


        • Hi Lisa, I’m sorry to hear that you are having trouble with your Sunny bike. Please call Sunny at 1-877-907-8669 to resolve the issue.

          Best regards,



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