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Mongoose

Mongoose Flatrock Mountain Bike, 24, 26 or 29 Inch Bike for Youth and Adults, 7 or 21 Speed, Aluminum Frame, Suspension Fork, Twist Shifters, Linear Pull Brakes, for Adults, Boys and Girls

Based on 386 reviews
Condition: New
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$509.99

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At a glance

Condition
New
Color
Purple
Size
16-in Frame/26-in Wheels
Model
R5837
Material
Aluminum
Bike Type
Mountain Bike
Wheel Size
26 in
In the box
Flatrock Bike
Warranty
Limited Lifetime

Features 5

  • Hardtail MTB with a lightweight 6061 aluminum frame and 26-inch wheels is perfect for all terrain adventures, best fit to riders 5'4" to 6'2" tall
  • Element suspension fork improves performance and control while providing a smoother ride
  • 21-speed twist shifters and rear derailleur provide effortless gear changes when riding up an incline or speeding down a decline
  • Reliably stop with confidence using the front and rear alloy v-brakes, delivering dependable stopping power

Description

Adventure starts where the pavement ends with the Mongoose Flatrock, an adults or kids mountain bike built for all-terrain fun. With 24, 26 or 29-inch wheels, this adults and boys and girls mountain bike is ideal for riders between 4'4"" - 6'0"", perfect for bringing explorers into the action. Its knobby mountain tires with an improved tread pattern provide superior traction and stability. The aluminum mountain frame is easy to handle while offering a clean look with its sloping top tube. Equipped with twist shifters, this 21 or 7-speed bike ensures smooth shifting and the right gear for tackling hills and descents. Linear pull brakes provide reliable stopping power, keeping riders in control on paved, dirt and crushed gravel terrain. Whether taking on the trail or cruising the neighborhood, the Flatrock is ready for the adventure. Assembly is easy with a few common household tools and the included instruction guide. At Mongoose, we know our roots – as pioneers in BMX and action sports for over 50 years, we're dedicated to delivering an epic ride every time. Get ready to push the limits

Specs 30

Bike Type Mountain Bike
Age Range (Description) Adult
Brand Mongoose
Number of Speeds 21
Color Purple
Wheel Size 26 Inches
Frame Material Aluminum
Suspension Type Front

Frequently asked questions

This product is currently out of stock. Please check back later for shipping info.

Yes, absolutely! You may return this product for a full refund within 30 days of receiving it.

To initiate a return, please visit our Returns Center.

View our full returns policy here.

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Top Amazon Reviews

My Go-To for Fun and Adventure!
If you're looking for a bike that's ready for anything, whether it's cruising around the neighborhood or hitting some easy trails, the Mongoose Flatrock is an awesome choice. I've been riding mine, and it's just a fantastic, reliable bike that makes getting out and about a joy. First off, it's really comfortable to ride. The front suspension (that's the "hardtail" part, meaning suspension in the front fork) does a great job soaking up bumps and uneven paths, so your arms and body don't take a beating. This makes longer rides or slightly rougher terrain much more enjoyable. Changing gears is super easy with the 21-speed twist shifters. Whether you're going uphill and need a lower gear, or flying downhill and want to pick up speed, a simple twist of the wrist gets you where you need to be. It shifts smoothly, so you're never struggling to find the right gear. I also really appreciate how lightweight yet sturdy it feels. It's easy to maneuver, which is great for weaving through paths or even just getting it on and off a bike rack. And when you need to stop, the brakes are reliable and give you plenty of stopping power. Overall, the Mongoose Flatrock is a fantastic bike for anyone who wants to enjoy the outdoors. It's built tough, rides smoothly, and is just a lot of fun. Whether you're a casual rider or looking to explore a bit more, this bike is a great companion! ... show more
Reviewed in the United States on May 22, 2025 by Burning Man
Doesn’t come with tools
Color: Grey Size: 17-Inch Frame/26-Inch Wheels
Hard to assemble really good quality delayed 2 times size is good good for its money does not come with tools to assemble the bike.
Reviewed in the United States on June 11, 2025 by Syed Abbas
Easy to Assemble and Meets My Needs
Color: Purple Size: 16-Inch Frame/26-Inch Wheels
I live in a medium-sized neighborhood; I bought this bike to more easily travel within my neighborhood without having to use my car for very short trips. I have never assembled a bike before, but I was able to assemble this one quite easily. The instructions were a bit confusing, because instructions are included for several different versions of the bike, but once I acclimated to which instructions were applicable to me, it wasn't very hard. I did have to purchase a few items for assembly, but they were not very costly, and they will be useful additions to my toolbox. Assembly really only entailed attaching the handlebars, seat and pedals. All of the gear mechanism was already assembled. The bike is easy to ride and operate. So far, I'm completely satisfied with this purchase! ... show more
Reviewed in the United States on October 20, 2022 by Wendi McDaniel
Mongoose bike
My grandson was delighted !!
Reviewed in the United States on December 14, 2024 by Kindle Customer
Not well made, parts already braking, no customer support
Color: Red Size: 18-Inch Frame/29-Inch Wheels
My husband and I recently bought the above bike on Amazon for our son for his birthday. We studied reviews and felt good about this being a good bike for a big kid--he's almost 6' and a stout guy. He loved the look of the bike; however, after a couple weeks of use, we've been very disappointed in the quality and functions of the bike. Here are several items of note: 1) The handle bar--this bar, although sleek looking, does not offer much room for adjustment and it is very uncomfortable, even painful, to ride for our son, me (5'8") and my husband (6'1"). We all experienced pinched shoulders and neck even after riding it just around the block. A neighbor helped us put a different handlebar in to raise the grip a bit, and although it helps, it's not quite the right size for the bike, the overall grip is still pretty narrow. Which means we will have to keep shopping around to make adjustments. 2) The handle grips and gear shift--these are entirely too small and spaced too close together! My son's hand, if he grips with a standard 4 finger grip, overlaps with the gear shift, so gears are shifting when he's just holding on to the handlebars and not meaning to shift gears. 3) The pedal/crank set--there is a decent amount of wiggle room in this. As I understand, this should be a pretty sturdy feel, but it jiggles. It doesn't appear that this is anything we can adjust, it is as it came. We had the bike professionally put together, and the mechanic noted this right away. 4) The kickstand--it has already bent and bends forward with the weight of the bike and no longer works. Overall, we are extremely disappointed in this bike. We feel that for the money, we shouldn't be having all these issues right away with it. We reached out to the manufacturer, and have not heard any response back. I'd shop for a different bike! ... show more
Reviewed in the United States on August 2, 2023 by Joe Wilkins
Puede mejorar la calidad
Color: Red Size: 18-Inch Frame/29-Inch Wheels
Par de rasguños y las gráficas como mal pegadas con bolsitas en algunas partes . 👍🏼
Reviewed in the United States on May 20, 2025 by Edgar Ortiz
Mongoose Bikes At Their Best!!
Color: Red Size: 18-Inch Frame/29-Inch Wheels
Legendary reliability and development on full display with this large, capable, and comfortable Mongoose mountain bike!
Reviewed in the United States on September 5, 2024 by Carlos Ubirlea
Beautiful bike.
Beautiful bike. Had to get the tool separate to set it up. The set up was a bit more difficult than I anticipated, but defiantly worth it for the finished product. It had a quality frame and beautiful tires, as well as the beautiful blue color through out. Would recommend for an overall quality bike for anyone looking to purchase. Thanks to the seller. ... show more
Reviewed in the United States on January 17, 2025 by Amazon Customer
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