| Unit | Size | Supported weight | Resistance | Console | Warranty |
|---|---|---|---|---|---|
DEROFIT RB-512M Check Discounted Price | L:60.8" W:20" H:45" | 330 lbs | Eddy current, 32 levels | 12 programs, BMI, Recovery | Frame: 10 year Parts: 180 days |
The DEROFIT RB-512M is one of the recumbent exercise bikes released in 2022. It offers a similar range of features as the Sunny Health & Fitness SF-RB4880. However, it has a greater weight capacity and offers more resistance levels.
Key Features and Specifications
- Assembled dimensions: 60.8L x 20W x 45H inches (155L x 51W x 115H cm)
- Assembled weight: 137 lbs (62 kg)
- Weight capacity: 330 lbs (150 kg)
- Seat: Adjustable, mesh backrest
- Resistance: Eddy current, 32 level
- Console: 12 programs, recovery, body fat
- Extras: Device holder
- Warranty: Frame 10 years / Parts 180 days
Frame construction
The DEROFIT RB-512M is an exercise bike made for home use, though it has an overall construction similar to
commercial-grade bikes. Its frame is made of 10 mm steel tubing, double-coated with a corrosion-resistant paint finish black in color. The only exception is the seat slide rail which is made of stainless steel.
The bike also integrates several non-metallic parts. The most notable ones are the guards of the drive system, the guards of the seat base, the frame of the backrest, the console casing, and several other covers. These are all made from a tough thermoplastic material.
The bike is fairly heavy. Its net weight is approx. 137 lbs (62 kg). Therefore, the packaged unit requires two persons for transport. However, once the bike is assembled, it can easily be moved by only one person as its front base is equipped with transport wheels. Also, both base stabilizer bars have adjustable levelers.
The bike is pretty large as well. Its footprint is approx. 60.8″L x 20″W (155 x 51 cm). Plus, it is recommended to allow at least two feet of clearance all around it for easy access and safe usage.
One last aspect to mention here regards the step-through feature. Not all recumbent exercise bikes have this type of design. There is quite a bit of a gap between the seat frame section and the front-drive unit of the bike which promotes an easy entry and exit.
Seat and handlebars
The DEROFIT RB-512M recumbent bike is equipped with a seat designed for superior comfort. Its bottom section features
a thick layer of padding. The backrest has a mesh structure for improved breathability; it’s built on a durable and flexible thermoplastic frame. It is also curved for superior lumbar support.
The seat is adjustable. It slides on a heavy-duty stainless steel rail. The applicable user inseam range for the bike is 25″ – 34″ (63.5 – 86.3 cm). In other words, it should be able to accommodate users between 5’0″ and 6’4″ (153 – 193 cm) with no problem. It also has an excellent user weight limit of 330 lbs (150 kg), similar to commercial-grade recumbent bikes.
The adjustment system is lever-based. The seat assembly features a lever that you can easily pull while you are seated in order to adjust the position of the seat. It’s also important to mention here that the backrest does not adjust independently from the rest of the seat. It does not recline, nor does have a vertical slider.
The DEROFIT recumbent bike is equipped with two sets of handlebars. One attaches to the bike’s front mast, the other to the seat assembly. The seat handlebars are equipped with pulse sensors; they do not adjust independently from the rest of the seat. The distance between them is approx. 20″ (51 cm).
The front handlebars are adjustable. They attach to the front mast via a small knob which you can untighten to adjust their angle. The front mast of the bike is also curved towards the seat, so if you want to exercise while holding the front handlebars, you won’t have an awkward posture.
Resistance system
The DEROFIT RB-512M is equipped with an eddy current resistance system. Although it’s not self-powered (it does not
have an internal generator to create power for the console when you pedal), it does have an internal motor and needs to be connected to an external power source. A power adapter with cable is included with it.
The bike’s resistance system uses a magnetic brake which is connected to the internal servo motor which basically makes the connection between the console and the brake. Thus, when you adjust the resistance from the console, or when a program is in use, the motor changes the magnets’ pull, increasing or decreasing the pedaling difficulty.
This motorized magnetic brake comes with several main advantages. First of all, the brake does not touch the internal flywheel. Therefore, the pedaling motion is very smooth and quiet. Second of all, since there is no internal friction, the brake will never wear out and does not require lubrication or replacement.
The bike’s console makes available 32 resistance levels. The lowest levels deliver a fairly light pedaling difficulty great for recovery training or workout warm-ups. Conversely, the highest resistance levels simulate a hill climb, providing quite a challenge even for an advanced user.
Drive system
Like most other recumbent exercise bikes, the DEROFIT RB-512M has an internal flywheel. Its exact weight is 
not specified, but considering that the bike weighs over 100 lbs, the flywheel probably weighs around 20 lbs (9 kg). It is perimeter-weighted in order to provide superior inertia and a smooth pedaling motion.
The bike’s flywheel allows reverse pedaling. This is a plus because you can alternate forward with reverse pedaling sessions in order to focus different muscle groups. But it’s important to mention that you cannot coast on this bike as it would be possible on a regular road bike. Also, when pedaling in reverse, the resistance remains constant, given by the selected level on the console, and the monitor continues to count distance, calories, etc, based on the internal flywheel rotations.
The bike is equipped with a belt drive system. It uses a poly-v rubber belt highly resistant to abrasion and stretching, designed for superior traction. As opposed to a chain drive, the belt drive comes with a few advantages. For example, you won’t have to take the bike’s front unit apart to lubricate the drivetrain. Also, the belt generates less vibration than a chain.
Although the bike’s crankset is not meant for standing on the pedals, it is pretty durable, featuring long steel arms similar to road bikes. The pedals are made from a durable nylon material featuring a textured surface and straps so you can secure your feet on them, if necessary. They also have weight elements on the bottom and they self-level whenever you remove your feet from them.
Console
The DEROFIT RB-512M bike is equipped with a fairly decent console. Although it does not have online connectivity, 
nor is compatible with any fitness apps, it does offer plenty of programs to keep you motivated. It features an LCD display with blue backlight split into several sub-sections in order to show as many workout metrics as possible at once.
The monitor unit tracks time, speed, distance, watts, RPM, calories, and pulse. Speed and distance are by default set to British Imperial units (MPH and miles) but you can set them to metric units (KMH and kilometers). The pulse reading function is grip only. The console can only read your pulse if you hold on to the sensors integrated into the seat handlebars. It cannot read pulse from a wireless transmitter.
The console offers a manual program, 12 pre-set programs, a pulse recovery function, and a body fat program. The manual program is the basic training mode. If using this mode, you will have to manually adjust the resistance from the knob on the console. In manual mode, you can also set workout goals for time, distance, and calories.
The 12 pre-set programs have their segment layouts marked on the console. Some of them have an ascension layout, others have an interval layout, while others progressively increase then decrease the resistance. They’re meant to cover most types of workouts that you can perform on a recumbent bike. Finally, the pulse recovery function and the body fat function have their own quick access keys on the console. The recovery function counts your heart rate at the end of the workout, determines how fast your pulse returns to a normal BPM, and based on the result, it gives you a fitness score between F1 (excellent) and F6 (poor). The body fat program calculates your body fat percentage based on your data input (age, sex, weight, height).
The console does not have integrated speakers, a workout fan, or online connectivity, but does have a device holder. It consists of two small plastic “hooks” at the base of the unit which can hold your tablet or phone.
Assembly and Maintenance
The bike’s base frame with the drive and resistance elements comes pre-assembled. The rest of the parts require user assembly. You will basically have to attach the two base stabilizers, the console mast, the seat frame with the rail, the seat, the handlebars, the pedals, and the console. This may take up to two hours of your time, but the task is not too complicated. The manual provides step-by-step assembly instructions accompanied by schematics. A basic toolkit is also included.
Once the bike is assembled, you don’t have to worry too much about maintenance. The internal parts don’t need lubrication. So, you only have to keep the bike clean and periodically check for loose bolts and parts.
The Pros
- Sturdy, steel frame – 330 lbs capacity;
- Adjustable, rubberized levelers on both base tubes;
- Transport wheels on the front base tube;
- Step-through frame design for easy access to the seat;
- Seat handlebars with pulse sensors;
- Adjustable front handlebars;
- Thick cushioning on the seat pad for extra comfort;
- Flexible and breathable mesh backrest;
- Easy adjustment system (lever) for the seat;
- Weighted pedals with adjustable straps;
- Motorized magnetic resistance system (32 levels);
- Multi-function console – it tracks time, distance, speed, RPM, watts, calories, and pulse;
- 12 pre-set workout programs;
- Body Fat calculator;
- Recovery function;
- Device holder included;
- Fairly easy to assemble;
- Little maintenance required;
- Excellent warranty.
The Cons
- No bottle holder;
- No online connectivity.
Summary
The DEROFIT RB-512M is a recumbent exercise bike made for home use. It features a 32-level motorized magnetic resistance system, a high-comfort seat with mesh backrest and lever adjustment system, and a console with 12 workout programs. It also has sturdy construction with a maximum user weight limit of 330 lbs (150 kg). It’s a recumbent bike for users of all levels, for recovery training, muscle toning, stamina development, and weight loss.