

🚴♂️ Ride Smart, Ride Silent, Ride Strong — Your Ultimate Home Spin Upgrade!
The Sunny Health & Fitness SF-B1851 Indoor Cycling Bike combines a robust 40-lb cast-iron flywheel with whisper-quiet belt drive and micro-adjustable magnetic resistance, delivering a smooth, customizable workout experience. Designed for professional-grade performance at home, it features pulse-sensing handles, a clear LCD monitor, and a tablet mount compatible with the SunnyFit app’s 1000+ workouts. Its ergonomic 4-way adjustable seat and 2-way handlebars ensure personalized comfort, while a sturdy alloy steel frame supports users up to 300 lbs. Perfect for millennials seeking an efficient, space-conscious cardio solution that blends tech-savvy tracking with durable design.





















| ASIN | B07Z45R1RT |
| Best Sellers Rank | #130,839 in Sports & Outdoors ( See Top 100 in Sports & Outdoors ) #165 in Exercise Bikes |
| Brand | Sunny Health & Fitness |
| Brand Name | Sunny Health & Fitness |
| Color | Silver |
| Customer Reviews | 4.3 out of 5 stars 2,379 Reviews |
| Drive System | Belt |
| Global Trade Identification Number | 00815749012432 |
| Handle Material | Alloy Steel |
| Included Components | 2 AAA Battery, Assembly Hardware & Tools, Magnetic Exercise Bike, User Manual |
| Item Dimensions D x W x H | 22"D x 49"W x 46.5"H |
| Item Weight | 50 Kilograms |
| Manufacturer | Sunny Health & Fitness |
| Material | Alloy Steel |
| Maximum Height | 84 Inches |
| Maximum Weight Recommendation | 300 Pounds |
| Minimum Height | 152.4 Centimeters |
| Model Name | SF-B1851 |
| Model Number | SF-B1851 |
| Power Source | Battery Powered |
| Recommended Uses For Product | Indoor |
| Resistance Mechanism | Magnetic |
| Special Feature | Adjustable Seat |
| Special Features | Adjustable Seat |
| UPC | 815749012432 |
| Unit Count | 1.00 Pack |
P**P
Excellent Peloton DIY
My local gym was closed for months, was able to open for a short time, and recently closed down again. So during this COVID time, I need something that I can do at home. I live in MN, and exercise outside in the winter is not an option for me. I have not taken a spin class for 15 years, but a spin bike is more in my budget than a treadmill. Plus, treadmills need a lot more space and when they break down the fixing can be pricey. So, spin bike, here we go! Like other reviewers, I wanted a Peloton, however, let's be real if you are looking at this bike, spending $2500 on a bike plus monthly subscription of $40 is probably not in your budget either! You are benefiting from my research! As I looked, there is pretty much a bike for everyone's budget. I am keeping my gym membership, so I did not want to spend an exorbitant amount. I was going to get one with a belt and 45-pound flywheel, but then I stumbled upon this one. The availability, magnetic wheel, price, super fast Amazon Prime shipping, the iPad shelf, and the "computer" are what sold me. I have seen a few reviews with damaged boxes, mine was fine, and I think the great packing job would totally protect the bike. It took about 30 minutes to assemble...thank you for your help, Husband! Once put together, it was easy for him to carry it to the next room (probs about 80 pounds). I have the bike in a carpeted room with a plastic chair mat under it. I will not be rolling it around, but I think it would be pretty easy. I am 140 pounds and am 5'6". The bike is sturdy, I feel totally safe when I am up out of the saddle. Speaking of saddles, I replaced the giant seat right away. I got this one: https://www.amazon.com/gp/product/B0845PGYYZ/ref=ppx_yo_dt_b_asin_title_o05_s02?ie=UTF8&psc=1 I may upgrade again or add a cushion, but I did not want to spend too much without being able to try it out. I have to (or should I say my backside has to) get used to spinning again! I knew the seat the bike comes with would be much too large for my preference. The size I got is more in line with the size of the seat on my road bike. I also upgraded the pedals. I want to use my road bike shoes (way more productive), so I got these pedals in the event my husband gets an inkling to go for a ride. I can clip in on one side, and he can use the cages on the other side. A nice compromise. https://www.amazon.com/gp/product/B081BDDGJ8/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1 If you want to use your road bike shoes exclusively, I'd recommend these: https://www.amazon.com/gp/product/B000KC3Y0G/ref=ppx_yo_dt_b_asin_title_o06_s00?ie=UTF8&psc=1 The bike is silent! I mean silent! I'm pretty sure the magnetic resistance attributes to how quiet it is and, there should not really be any maintenance. The iPad holder and the stat reader are great. I only look at the rpm's (same as Peloton's "cadence") when I ride. The tracker goes between time, speed, distance, calorie, odometer, RPM, and Pulse. It is important to know that this device will not give you the most accurate readings of your performance because it has no way of knowing your body size and conditioning level. So expect them to be relatively generic. I use my own heart rate monitor and I still have to get an iPhone holder that I can attach to the bike, so I can see my heart rate app on my phone easier. I bought the Peloton app for $12/month (I did the 30-day free trial first) and watch it on my iPad. The iPad is quite secure in the holder. If you have a ROKU, you can watch the Peloton classes on your tv! The bike does not come with weight holders, and it is kind of annoying that you cannot buy the ones Sunny puts on the higher price point bikes a la carte. So, I am going to pay about $45 to get them on Etsy. I think the reason the other Sunny bikes are more money is that you would not have to "DIY" them. They come with weight holders and such.... I am COMPLETELY satisfied with my purchase! I think spinning would suck without the Peleton app (or another app or YouTube videos)...I mean it is pretty boring to just sit and pedal. Ride on, people. EDIT: A few people asked for some pics of the seat installation (I changed out the seat), and the tablet holder.
M**N
Fantastic Stationary Bike - Perfect for Great Cardio Workouts
I spent several hours reading the reviews of all stationary bikes that met my criteria: 1. In stock w/free shipping; 2. Priced in the $300 - $400 range; 3. Four or more stars average review; 4. Newer model (not older than 2019); and 5. Magnetic resistance. There were a few that met all or most of these criteria, but this Sunny model had the overall best reviews and shipped the quickest (4 days from date of purchase), so I went with it. I'm really glad I did and I couldn't be happier. The bike was extremely well packed with plenty of protective wrap - in fact, it took about 20 minutes, give or take, just to get everything out of the box and unwrapped. It took another 35 minutes or so to assemble, and it was very easy to follow the directions. All of the necessary tools were included, which was nice if not completely necessary for me. I assembled it myself, which was no problem whatsoever. All parts were very well marked and the directions were clear. I've had the bike for 2 weeks now and have used it every other day. It operates as close to silently as any stationary bike I've ever used - it's really super quiet with no chance of it disturbing anyone. The resistance knob works smoothly, and with a couple full twists you will really feel the burn. A few people have asked if you can ride standing up, and yes, with the tension high enough, that was possible for me. I've never taken a spin class, so I don't know how this compares with what you'd use in a gym, but this really is just perfect for my needs. If it helps: I am in my mid-50's, 5 foot 11, and have about 20 - 25 pounds of winter/COVID weight I'd like to shed by Spring. This bike will definitely help me get there. The ride is comfortable and so smooth that I really enjoy working out on it. I signed up for a trial of the Peloton app and was able to do a couple HIIT workouts on this bike. Great workout, but I'll probably cancel the subscription once the trial ends, as I don't really need the encouragement or the routines provided by paid online classes. The only two slightly negative things I'll share are really just ideas for improvement: a. I wish the monitor that it comes with had a backlight , as I tend to work out with the lights out so I can better see my tv. This is a very specific wish list item, but it would definitely be useful to me, as I cannot see the monitor at all in the dark. Hardly a design flaw - I can't see most things in the dark! b. I wish the wheels that make it portable were a little larger and that I didn't have to tilt the bike quite so much to be able to access the wheels. In a large room with little furniture, this wouldn't be an issue at all, but in a confined space, it can be tricky to maneuver the bike and access the wheels for easy transport. I do, however, believe that this is a pretty standard design for this class of bike, and I doubt that other models implement this feature in a materially different way. Bottom line: the excellent reviews for this bike are definitely warranted. Workouts are fun, comfortable, efficient, and injury-free! I love this bike and would definitely recommend to anyone in the market with criteria similar to mine.
G**D
Solid, Silent, Smooth, Needs a Little Work
This bike is gym-quality. Solid, silent, smooth. Easy to assemble. I’d give it five stars except the dumbbell holder, which was a major selling point, feels like an afterthought. The weights keep falling off. A little more engineering could have solved this. And the seat is uncomfortable. I shouldn’t have to buy an additional seat pad.
E**A
Great Entry Level Bike
As someone who is totally new to spinning, I am very, very happy with this bike. Assembly was easy, as the frame of the bike ships in one large piece and you just have to attach the peripherals (handlebars, seat, pedals, computer, etc). I took my time at each step, and felt the process was pretty easy. Just be particularly careful when attaching the pedals. I think because the crank arms are attached to the main frame when the bike ships, if you were to strip the threads in a crank arm while assembling the pedals, you might need to replace the entire frame. The components of the bike feel pretty high quality, the only shoddy component I noticed was a kind of weird, messily superglued wire with slightly exposed insulation running to my pedals (pictures attached). I am guessing this is the RPM sensor? Kind of not great, but I have a wahoo cadence sensor anyway, so I'm not worried about the RPM monitor being a bit questionably installed. The RPM monitor still seems to work perfectly at the moment, and the messy glue isn't noticeable as it's fairly small/unobtrusive (and on the left side of the bike, which currently faces my wall). It is nice having the RPM monitor installed with the bike, as it does sense changes in my cadence just a *bit* faster than my wahoo cadence sensor, though I still like having the wahoo cadence monitor connected to my iPad so I can see a summary of my cadence throughout my workout, once I'm done. The bike seat is fine, though I got a gel seat cushion to help improve comfort. The handlebars are also fine. I thought the placement of the device stand might interfere with hand placement, but I actually don't find that to be the case. The best thing about this bike is that it is that the magnetic resistance allows it to be *silent.* I can crank the resistance up, stand out of the saddle, and still it makes no sound. It feels sturdy, both for me and my boyfriend, and the resistance is good enough for us. Though admittedly we are new to spinning, and don't really need heavy resistance yet. As a fairly small, 5'4" new spinner, I don't even get (anywhere) close to full resistance when working out, in the saddle or out of it. Maybe one day down the line we will upgrade to something with a heavier flywheel, but this is absolutely perfect for us for now (and hopefully the next few years). I'm very satisfied with this purchase, and (when combined with the peloton app), I'm loving being able to access spin classes from the comfort of my living room! UPDATE AFTER OVER A YEAR: I love this thing so much. I have had to do nothing in terms of maintaining the bike, the magnetic belt drive is so convenient. I ride 2-4 times per week, and it's so nice to have access to an easy workout in my living room. I still find that it has plenty of resistance to make my legs jelly. RPM monitor is still working perfectly. I love to putting my tablet on the tablet stand and doing a Peloton workout, but cannot imagine ever buying their bike. There is no way that the cost of their bike reflects a commensurate improvement in user experience (especially when you buy cheap a cadence sensor and heart rate monitor, and can see those on your tablet screen while you workout). I feel like I'm getting 90% of the peloton experience at a fraction of the cost. 5/5 love this bike
A**H
EXTREMELY Happy Customer
I purchased this bike to help me with my blood sugar control as I am pre-diabetic and doing my best to stay off any medication. Because of this I find it necessary to be able to exercise everyday, no matter what kind of weather. Thankfully, I live in Florida which makes it very easy to vary my exercise regimen. However, there are those occasional rainy days and hot summers make it difficult. Let me begin by saying my fiance is a very experienced road rider and mountain biker. He also taught indoor spin classes for several years, so he has been on a lot of stationary bikes. Lucky for me, he is the one who assembled bike! LOL He was able to put it together in about 20 minutes. It would definitely have taken me a LOT longer, but I probably could have accomplished it by following the directions. Once assembled, it took a few minor tweaks to the pedals but it was relatively easy and straightforward. I have had the bike for several months now, and I have to say we are BOTH extremely pleased with the product! I rely a great deal on my fiance's input because he has ridden so many different bikes. He is very impressed with the quality and strength of the bike, considering its price! I am 5'6,150 lbs, and he is 6'3", 180 lbs, and we both are comfortable on it. The handlebar height is adjustable, and the seat is adjustable in both height and distance to the handlebars. The bike is VERY quiet, with only a slight creak when I cycle standing up, which is really nice to be able to give my bum a break! Fiance says he will make an adjustment to tighten things up a bit to eliminate that issue. The saddle is a pro riding saddle, and therefore will require cycling shorts and a period of breaking in, but after about a month of riding 3-4 times a week, I am able to ride for an hour pretty comfortably. As I said, the bike is VERY sturdy and well-built, and my fiance says it measures up quite well against many of the bikes he has used as a spin class instructor, just without the bells and whistles. It does have a pretty nice on board computer which tracks multiple types of stats. The heart rate monitor is spot on when compared to my Polar, and the stats will either scroll through or remain on one stat (like time elapsed), with a 2 second hold of the button. The handlebars are very comfortable, and there are several places to hold on or to use for your phone or tablet. It doesn't have a bottle holder, but there is a holder for 2 dumbbells, which I don't really use. One of the only slight drawbacks for this bike is the way to increase or decrease resistance. Like some of the older spin bikes, it has a knob that you turn, and is therefore quite unscientific. However, for my purposes it is sufficient as I simply turn it 1 to 1 1/2 times to increase or decrease. The magnetic resistance is very powerful, and my fiance likes that the resistance is smooth and doesn't cause any friction on any other parts. To us, it's definitely worth spending the extra money on the magnetic resistance. Overall, this is a FANTASTIC bike for the money, and my VERY perfectionist (when it comes to riding) fiance is extremely impressed! I wouldn't think of spending thousands on a Peloton just to get a few more tricks and the "luxury" of paying for a gym membership on top of that! Just put on YouTube and find any one of the numerous videos with cycling instructors or a loverly ride through the Italian alps (we have a 4K projector, so our screen is a whopping 10 feet across, and you feel like you are THERE!!). I feel that if you choose to buy this bike, you won't be disappointed. We haven't had any problems that require a call to customer support, so I can't speak to that issue. But we are extremely satisfied customers, and would recommend this bike to anyone looking to get or stay healthy when working out is so difficult during Covid. And in conclusion, I would like to say I have not been compensated in ANY way for this review. I haven't received any discounts or free products for writing it. I just hope to help others trying to make a sound decision on spending a significant amount of money on a product that would be difficult to return!! HAPPY CYCLING!!
J**D
Great first impressions
I'll update this in the future but I just wanted to give my first impressions. First impressions are this is a great deal. It was on sale for 50% off with a total $189. I've been waiting for a couple of years before buying this bike. The packing was a little beat up at on the bottom side. When taking it out of the box there were several zip ties and such that fell out. Luckily there didn't seem to be any damage to the bike. It took about an hour to set up. Not to difficult but I did take my time. The foot print is small which is nice. I immediately rode it for about 25 minutes. Going to have to adjust a little more but overall it's a solid bike and it'll give me an opportunity to burn some calories when it's to cold or to hot outside. The ride was smooth. I'm not sure the resistance but I kept moving it up and down a few times. No reason than to mess it it. I ride my bike to work on the regular and as I rode to work this morning I certainly want to try to set it up as close to that feel if possible. On the fly and first time it's pretty easy to adjust as you need. Overall I'm pretty happy with this purchase. I didn't want to pay a super high price but I didn't want to skimp. I'm not sure it's worth the $380 or so MSRP but something that's going to give you a decent work out it's well worth 50% of that and you know they are still making money. So keep an eye out and hit those sales and enjoy the ride inside!
S**S
It works great... until you need to replace parts!
TL;DR: Unless you love a good DIY project you might want to order a better quality product. **Second edit - Trying to get this bike apart has been the bane of my existence. It's involved two of us using a pipe wrench, as this thing is so tightly wedged together nothing budges. It took full hours of trying to get the crank off. Now, the axel won't budge. The videos they send you show all the parts sliding out with ease. It took a total of six days - approximately 8 hours total - to get the bike apart and reassembled. Since some of the parts were absolutely destroyed in the process I spent my own money at a bike shop to get this thing cobbled back together. The good news is the fix worked, and now I know exactly how much force this bike is going to take to get it apart. As I mentioned below, this bike was great. Unfortunately, the way it comes from the factory this thing is practically welded together and it will take you HOURS to make that first repair. Hopefully, since we put it back together ourselves, the next repair won't be as difficult. ***Edit after only 3 months: This bike developed a very, VERY terrible "clunking" sound when the pedal was in a particular position. After doing some googling, it seemed a bearing needed replaced. Sunny confirmed this and let me know they'd send the bearings. However, I went ahead and ordered the bearing and a crank puller myself. Despite customer service telling me what size puller to get, the size of the crank bolts, and the bearing model, it has quickly turned into a nightmare. The nuts stripped when trying to remove them (both crank nuts), the size crank puller they told me to get had to be man-handled with a PIPE WRENCH to even get them to thread, and the stripped nuts now have to be replaced as well. A 20-minute job turned into a four hour ordeal and my bike is now in pieces. I have had the bike for less than three months and it has less than 700 miles on it. ***Original review: I am the kind of person who researches the heck out of something before I buy it. TL;DR this bike is perfect for someone getting into cycling who is under 265 lb (the weight limit) and doesn't mind a machine that doesn't make the adjustments for them. Longer review below: I bought this bike to use with iFit. I have a treadmill from a compatible iFit brand and the customer service and quality of the machine made me dread buying a bike from them. I love the features of iFit and I love that it offers so much more than the traditional studio class, so I knew I would have to buy a bike that was incompatible. I also wanted to avoid buying another brand, like Bowflex or Peloton or any of the other name brand bikes, mostly because I don't want ANOTHER fitness app. I'm happy with mine and honestly don't want to pay for a gym membership and two fitness apps every single month. After a lot of research and looking at several other brands, I came to this one. What drew me is what probably drew you - the person who "hacked" their bike into a Peloton. I knew I personally wanted a silent, magnetic bike with interchangeable parts - like pedals and seat. So far I have not changed those yet, but I plan to in the future. Things other people will say in negative reviews you might worry about (like I did): "This seat is uncomfortable" - that's biking y'all. Buy yourself a pair of $10 biking shorts on here when you buy this bike. After a few weeks you won't need them anymore. This seat for a spin bike is a cushy, comfortable seat that is incredible padded. "It makes a knocking noise when I pedal" - sure does... when your pedal cage fastener hits the pedal it will indeed make a knocking noise. Move the metal fastener and it won't do it again. "It's unstable when I stand up" - There are four adjustable feet on this thing. Make some micro adjustments and it will be still and sturdy. "The pedals don't assemble right/fall off/strip when I try to use them" - Sunny has a 45 second video to demonstrate how to put these pedals on - just google Sunny Bike Pedal Installation and you'll find it. "The seat won't tighten and falls everywhere" - It honestly will with the tools provided. You're gonna have to adjust it a few times the first few times you ride the bike. So, if you're still reading I assembled this bike by myself in approximately half an hour. I watched the above-mentioned video to install the pedals because I was terrified I would screw them up because the directions are SO DANG SPECIFIC so you don't install them wrong. Thirty minutes and I was on and riding. All the little things above I experienced myself with the bike... and they were all super easy fixes. I had to make a few adjustments the first few times I rode, including with the seat several times before I got it locked in just right. Using this with iFit has been super simple once I figured out the whole RPM/RPE thing and the simple computer console on this bike let's me do everything I could on a fancier bike. For those who want to use iFit, when you use incompatible equipment you'll see a resistance level broadcast on your screen. From what I've seen so far it only goes to 5. I turn the resistance wheel two full times to get it at the "level" broadcast on the screen. I start at zero and in the warm up cycle I turn it two full times to be at a 1 level. Two more full turns for each level of resistance up to 5. If it looks like we're going up a hill, I do one full turn to add some more and move it back down when it levels out. I've found with this little system of mine I can keep the RPMs they call for while still getting a workout. I've ridden over 120 miles on this bike in the 3 weeks since I've bought it and I couldn't be happier with this purchase. I manually upload my ride to keep track of the mileage weekly on Strava, but honestly the Wahoo Cadence Sensor may be my next purchase since I love this bike so much. It's absolutely silent, easy to assemble, solid, and simple to use. If you're looking for a cheap beginner's alternative to an expensive "smart bike" and app service, this is absolutely it. You won't be disappointed with this bike.
A**H
Amazing value for the price. Solid bike.
Great value. Bought it for the wife. She says she enjoys using it and is very sturdy. Great buy.
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1 month ago
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