| Unit | Size | Supported weight | Resistance | Console | Warranty |
|---|---|---|---|---|---|
ASUNA 5100 Check Discounted Price | L:52" W:21" H:47" | 300 lbs | Manual magnetic | No | Frame: 5 years Parts: 180 days |
Sunny Health & Fitness has come a long way during the past few years, clearly improving the quality in their products. The ASUNA products are some of their best, and when it comes to exercise bikes, the ASUNA 5100 has all the qualities of a gym grade spin bike.
This model is actually one of the newest for 2016. It has a similar construction to Schwinn Fitness AC Performance Plus, but features a resistance system similar to the Keiser M3 Plus. It costs at least $1,000 less than these two models though. Therefore, in case you want a heavy-duty exercise bike that can support spin training, the ASUNA 5100 is definitely worth looking into.
Technical Details and Specifications
- Assembled dimensions: 52L x 21W x 47H inches (132L x 53W x 119H cm)
- Assembled weight: 101 lbs (45.8 kg)
- Flywheel weight: 37.5 lbs (17 kg)
- Supported weight: 300 lbs (136 kg)
- Handlebars: 2-way adjustable
- Seat: 4-way adjustable
- Pedals: SPD clip and toe cages
- Drive mechanism: Belt
- Resistance: Magnetic, adjustable
- Bottle holder: Yes
- Performance monitor: No
- Warranty: Frame 5 years / Parts 180 days
Frame construction
To begin with, this ASUNA exercise bike does not have the same frame construction as the lighter model, the ASUNA 4100. Its frame is actually similar to the indoor cycling bike model that we’ve mentioned above, the Schwinn AC. Needless to say, it features a one-
piece steel frame, with a total assembled weight of 101 lbs (45.8 kg), weight which provides the required stability for spin workouts.
Most steel parts are double coated with corrosion resistant silver paint, except for the seat and handlebar posts, which are chrome-coated. The only plastic parts are the belt guard and several other protective covers, which have no role whatsoever within the bike’s overall sturdiness.
This Sunny exercise bike does not have an extremely large footprint. It definitely doesn’t require the space of a treadmill such as the 3G Cardio Pro for example. It takes only 52″L x 21″W (132 x 53 cm) of floor space, and requires about 1.5′ (46 cm) of clearance on each side, for proper and safe usage. Thus, it’s safe to say that the bike will fit with no problem even into a smaller room.
The bike’s bases are ovalized steel tubes which integrate adjustable stabilizers with rubber caps. These offer the possibility to achieve maximum stability and a good grip onto the floor, an important aspect for spin workouts. The front base features silicone transport wheels, which help with the relocation of the assembled bike. By leaning the bike forward on its wheels, you will actually be handling less than half of its total weight.
Seat and handlebars
The ASUNA 5100 by Sunny Health and Fitness features a 4-way adjustable seat. The saddle itself is not extremely comfortable, similar to the thin, aerodynamic seats of most speed bikes. But keep in mind that this bike is designed for spin and interval workouts, 
and the users shouldn’t spend the whole time of their workout in seated position. On the other hand, the seat features a simple connection mechanism to its post, therefore you should easily find a replacement for it. Or, in order to improve its comfort, you can add a sheepskin or gel cover on top of it. Also, due to the adjustment span of the seat post, the bike can accommodate users between 5’3″ – 6’5″ (160 – 195 cm).
The handlebars feature an ergonomic, multi-grip design. In fact, this handlebar offers several more holding positions than the handlebar assembly equipped on the Star Trac Spinner Blade. It’s fully covered by a sheet of rubber foam material in order to provide a comfortable grip. It’s also vertically adjustable, which adds to the amount of possible workout postures.
Both seat and handlebars feature sizeable adjustment knobs, making it extremely easy to adjust the bike’s dimensions, in case the bike will be used by persons of various sizes.
Resistance and drive
As opposed to the ASUNA 4100 which has a friction brake, the ASUNA 5100 features a manual magnetic resistance system. The knob on the main tube of the frame is connected to a magnetic element. By turning the knob, more or less magnets will go over the flywheel, increasing or decreasing drag. The knob also functions as an emergency brake. By pressing it down you can instantly stop the rotation of the flywheel. 
This exercise bike features a belt drive system, using a heavy-duty belt. This means you don’t have to lubricate the bike’s transmission, and also the pedaling is really smooth and quiet. The flywheel is perimeter-weighted, adding a lot of stability to the pedaling motion, and eliminating the “stair master” effect which may be present in other similar exercise bikes. It’s not the heaviest flywheel that you’ll find in a spin bike, but at 37.5 lbs (17 kg), it does offer quite a consistent momentum.
Needless to say, since it’s a bike made for spin workouts, the ASUNA 5100 features a really sturdy crankset, with solid stainless steel crank arms. The pedals supplied with the bike are metallic, with SPD clips and toe cages.
In case you’re wondering, you can pedal in reverse on this bike, but you cannot coast, as the flywheel and the pedals will complete at least a few more spins when you stop pedaling. Thus, before changing the course of pedaling, it’s best to use the emergency brake, in order to stop the flywheel and prevent any accidents.
Accessories
Unfortunately, this ASUNA indoor cycling bike does not come with a bike computer, so if you want one, you’ll have to purchase it separately and adapt it. The only accessories offered with this bike are the two plastic bottle holders, which attach to the front fork of the frame. Water bottles are not included.
Assembly and Maintenance
The flywheel, the crankset, the belt and resistance mechanism are already assembled and attached to the main frame, so we can say that the hardest assembly part has already been taken care of by the manufacturer. However the bike still requires some assembly. You will have to add the bases to the frame, the seat and handlebars, and the pedals, task which shouldn’t take more than 20 min. A hard copy of the owner’s manual which supplies step-by-step assembly instructions, is supplied with the package. The tools required for assembly are also included.
Since it’s a bike with magnetic resistance and a belt drive, maintenance doesn’t require much. Basically, you just have to wipe perspiration from the frame, and periodically check the bike’s bolts and screws to make sure they still hold tight in their places.
The Pros
- Solid frame, commercial quality construction;
- Elegant design;
- Small footprint, great choice for a cardio fitness machine if space is an issue;
- Handlebar with a multi-grip design;
- Superior micro-adjustability;
- Solid crank set, can support just about any spin workout;
- Hybrid pedals, with cleats for spin shoes, and with toe cages;
- Magnetic, frictionless resistance;
- Smooth and quiet belt drive;
- Little maintenance required;
- Extremely easy to put together;
- Excellent value for the price.
The Cons
- Handlebar only 2-way adjustable;
- No fitness meter.
Bottom Line
The ASUNA 5100 is an indoor cycling bike featuring a gym grade construction, with a user capacity up to 300 lbs. It’s a bike with manual magnetic resistance and a belt drive system, which means its operation is quiet, and maintenance is minimal. It’s an excellent exercise bike for users of all levels, great for intense cardio training, interval training, strength and stamina building, and for weight loss. Even though it’s not a cheap bike, it’s still way less expensive than various spin bike models. Therefore, it’s safe to say that it comes with an excellent price / quality ratio.