Sunny P8400 Recumbent Bike | Suitable for People with Bad Knees

Jazz up your home with the stylish pink Sunny P8400 Recumbent Bike. The P8400 is ideal for those who want to bring efficiency to their gym regimen. This pink recumbent bike has the visual appeal to be a permanent addition to your home gym.

Recumbent bikes can be suitable for people with bad knees who still want to achieve a low to moderate-impact workout. This Pink Recumbent bike has a fast and reliable magnetic resistance system that you can manually adjust between 8 levels. Therefore, your training can remain challenging and effective throughout your fitness journey.

The Sunny P8400 recumbent bike has a fitness monitor that features an LCD to monitor your speed, distance, heart rate, time, and calories. You will be able to see your results to keep you motivated and on pace. You can also monitor and maintain your target heart rate. For instance, the more steady and prolonged the elevated heart rate during the workout, the more calories get burned.

The P8400 also features an adjustable seat to attain the perfect workout posture. In addition, extra padding and cushion ensure proper blood flow in the glutes for prolonged and vigorous workouts. For example, the extra padding helps relieve pressure points in the tailbone due to sitting and reduces the “falling asleep feeling.”

Learn more in my complete review below!

Sunny P8400 Recumbent Bike
Sunny P8400 Recumbent Bike

Product: Sunny P8400 Recumbent Bike

Price: For a great deal on this bike, merely go here to Sunny Health &

Warranty: Frame 3 years / Parts 180 days

My rating: 8.5/10

Affiliate Disclosure: As an Amazon Affiliate Program participant, I earn commissions on purchases made through links in this post. Full disclosure

Details and Specifications

  • Assembled dimensions: 45L x 23W x 36.5H inches (114L x 58W x 93H cm)
  • Assembled weight: 48.5 lbs (22 kg)
  • Weight capacity: 220 lbs (100 kg)
  • Seat: Adjustable
  • Resistance: Manual magnetic, eight levels
  • Fitness Monitor: Time, distance, odometer, speed, calories, pulse, goals, scan
  • Warranty: Frame 3 years / Parts 180 days

P8400 Frame Construction

The Sunny P8400 recumbent bike features a 2-piece cylindrical steel tubing frame. The rear piece that holds the seat connects to the base tube with the front part with the drive and resistance elements. The longitudinal base bar of the back piece also acts as a seat adjustment section.

Sunny P8400 Recumbent Bike

All the steel parts in the bike’s construction come double-coated with a durable white paint finish. In addition, the bike also integrates several durable thermoplastic parts. The most notable ones are the drive system’s covers, the fitness monitor’s casing, and several other small parts such as adjustment knobs, base bar caps, etc.

In addition, the monitor and the drive system guards are pink for a warm, aesthetic touch, while the seat and the other plastic parts are black.

The Sunny P8400 is relatively small for a recumbent bike. With all the parts assembled, it is approximately 45″ (114 cm) long and 23″ (58 cm) wide. However, it still is advisable to allow at least two feet of clearance all around it for easy access and safe usage.

Furthermore, the bike is also pretty light. Its net weight is 48.5 lbs (22 kg). Therefore, one person can carry and assemble the bike. In addition, once completed, it is even easier to relocate as its front base comes equipped with transport wheels.

Seat and handlebars

The Sunny P8400 recumbent bike comes equipped with a seat for optimal comfort. The bottom pad is approx. 15″ (38 cm) wide and 10.5″ (26.6 cm) long, so it provides plenty of contact surface.

If you’re wondering, the seat height is approximately 20.47″ (52 cm) above the floor level. Both the seat and the backrest integrate approximately 2″ (5 cm) of foam padding and a thick vinyl cover, which is durable and easy to maintain.

The seat itself doesn’t attach to an adjustment rail like the seat of the XTERRA Fitness SB4500, for example. However, the whole rear frame section and the seat are adjustable. In addition, its base bar has several adjustment holes, and the bike comfortably accommodates users between 4’7″ and 5.7″ (140 – 170 cm).

Sunny P8400 Recumbent Bike
Sunny P8400 Recumbent Bike

Although taller persons may still be able to use the bike, they may not benefit from a complete leg extension. In addition, the seat has a maximum user weight limit of 220 lbs (100 kg).

The bike comes with two sets of handlebars. One attaches to the seat’s backbone, and the other welds to the front mast of the bike. The seat handlebars have a reasonably wide span. They integrate metallic pulse sensors, and the fitness monitor can track the pulse.

The front handlebars have shorter grips without any sensors. Instead, they’re slightly curved towards the user to reduce the awkwardness of the position if holding them. In addition, one of the handlebars is adjustable. Finally, both handlebar sets have PVC foam sleeves for improved contact.

P8400 Resistance system

The Sunny P8400 recumbent bike comes equipped with a manual magnetic resistance system. Therefore, you don’t need a power cord, power adapter, or an external power source. The only power source needed is a set of batteries for the fitness monitor.

The main resistance element is an internal magnetic brake that connects to the tension knob on the front tube of the bike via a steel cable. Therefore, if you turn the knob clockwise, the magnets will move closer to the bike’s flywheel, increasing the pedaling difficulty.

The bike’s magnetic resistance system comes with a few advantages. First, the pedaling motion is very smooth since the magnets don’t touch the flywheel. Second, since there is no internal friction, the bike generates almost no noise during use. And you don’t need to worry about used brake pads, their lubrication, or their replacement.

The bike has eight resistance settings. The first three levels deliver a relatively low pedaling difficulty, great for warm-ups or recovery training. Conversely, the 7-8 tension levels provide more resistance, remarkable for stamina development and stabilizing muscle.

Drive system

Sunny P8400 Recumbent Bike

The Sunny P8400 recumbent exercise bike comes equipped with a belt drive system. For instance, this stands for all exercise bikes with a magnetic resistance system. In addition, it integrates a poly-v belt designed for superior traction.

Unlike a chain drive, the belt does not require periodic lubrication. It also delivers a smoother motion than a chain, generating less vibration.

The bike’s internal inertial wheel is perimeter-weighted. Thus, it increases inertia and a more consistent overall pedaling motion. Its exact weight is not specified, but since the bike only weighs 48.5 lbs (22 kg), the flywheel probably doesn’t weigh more than 15 lbs (6.8 kg).

The flywheel is bi-directional. Therefore, you can pedal in reverse if you want. In addition, this allows focusing on different muscle groups and alternate forward pedaling sessions with backward pedaling sessions. However, coasting is not possible on this bike.

The bike’s crankset features cylindrical, chrome-plated arms. The pedals have a metallic core, but their outer shell is a thermoplastic material. However, they’re not meant for pedaling while standing up. Furthermore, they have adjustable straps and weight elements to self-level when you remove your feet from them.

P8400 Fitness monitor

The Sunny P8400 recumbent bike includes a fitness monitor that offers a few extra features over a simple model. It has an LCD that tracks time, speed, distance, total distance, calories, and pulse.

Unfortunately, the speed and distance are in Imperial units (MPH and miles), and there is no option for changing them to metric units. In addition, the pulse reading function is grip-only. Unfortunately, the monitor does not read your pulse from a wireless transmitter.

Sunny P8400 Recumbent Bike
Sunny P8400 Recumbent Bike

The monitor does not have Bluetooth connectivity, is not compatible with any fitness apps, and does not have pre-set programs. However, it has countdown modes for time, distance, and calories. Therefore, you can set a workout goal for these three metrics, and the monitor will count down from the selected value.

The fitness monitor has three buttons – Mode, Set, and Reset. The Mode button allows you to select the workout metric you want to view or the Scan Mode. The Reset button clears all the values on the monitor to zero except the odometer. Finally, the Set button is for setting the desired workout goals for time, distance, or calories burned.

The fitness monitor is battery-powered and requires a set of two AAA batteries. It begins tracking your workout data when you start pedaling. In addition, it also automatically turns off after a few minutes of inactivity on the bike. Furthermore, the monitor does not have a device holder.

P8400 Assembly and Maintenance

The front base unit of the bike with all the drive and resistance elements comes pre-assembled. However, the rest of the parts require user assembly. You will have to attach the front base bar, the front upright bar, and the fitness monitor, connect the rear frame part to the front frame part and add the seat pads and the pedals.

Consequently, it may take more than an hour of your time, but the manual provides pretty clear assembly instructions. In addition, all the tools necessary for the assembly come with the bike.

The internal parts shouldn’t need any lubrication for an extended time for maintenance. Therefore, you only need to wipe off the sweat that may fall on the frame at the end of the workout, keep the bike clean, and periodically inspect it to ensure that all the parts hold tight in their places and all the moving parts function correctly.


  • Pretty durable construction – can support users up to 220 lbs;

    Sunny P8400 Recumbent Bike
    Sunny P8400 Recumbent Bike
  • Adjustable levelers on the rear base bar;
  • Transport wheels on the front base bar;
  • Two sets of handlebars included;
  • Pulse sensors integrated into the seat handlebars;
  • Padded seat and backrest for superior comfort;
  • Frictionless magnetic resistance with eight distinct levels;
  • Weighted pedals with adjustable straps;
  • Fitness monitor included – it tracks time, distance, total distance, speed, calories, and pulse;
  • Goal settings for time, distance, and calories burned;
  • Easy to assemble;
  • Little to no maintenance is required.


  • There is no bottle holder;
  • There is no device holder;
  • No backlight on the fitness monitor LCD.

Sunny P8400 Recumbent Bike Summary

The Sunny Health & Fitness P8400 is a recumbent bike for home use. It has an 8-level manual magnetic resistance system, a comfortable seat, two sets of handlebars, and a fitness monitor that tracks the essential workout metrics.

In addition, it has a maximum user weight limit of up to 220 lbs and should accommodate users up to 5’7″. Moreover, it’s a bike for light to medium-intensity cardio workouts, muscle toning, stamina development, and weight loss.

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

Please note 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.

4 thoughts on “Sunny P8400 Recumbent Bike | Suitable for People with Bad Knees”

  1. Lovely piece of equipment. Usually, when I purchase equipment that cannot be easily stored under the bed or in the closet, it becomes a clothes rack. Therefore, I would prefer doing simple exercises such as step-ups or Pilates. I hate that I don’t know how to swim, or I would instead incorporate that into my exercise routine.

    • Hi Faye, thanks for stopping by and sharing your thoughts with us. Would you please let me know if I may further assist you with exercise equipment? I’m always happy to help.

      Kind regards, Robert

  2. I stumbled upon your review when searching for Recumbent Bikes, and yes. I do have bad knees. 

    As a former Olympic-level gymnast with MANY injuries during my career as an athlete, I sustained a life-long injury of bad knees. So this Sunny P8400 looks like a good option to get me back into the fitness game. 

    Do you know if the Sunny P8400 comes in different colors? I don’t mind pink but would prefer a different color if available. 


    • Hi Jay, thanks for stopping by and sharing your thoughts with us. Pink is the only color available for the P8400 bike. However, the Sunny SF-RB4905 bike has a similar design, is light gray, and it’s highly rated.

      Please let me know if I may further assist you with exercise equipment. I’m always happy to help.

      Kind regards, Robert


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