20" Mongoose Massif Boys' Fat Tire Mountain Bike, Black/Yellow

    • Share this:
    Share with a friend
    Sign into your email account to send this page to a friend:
    Outlook or Apple Mail
    or other default program

    Save $25 when you open a Walmart® Credit Card and spend $75 today.*

    *Offer subject to credit approval
    Learn More
    or Apply Now

    • Browse Related Products

    20" Mongoose Massif Boys' Fat Tire Mountain Bike, Black/Yellow

    Buy from Walmart

    Shipping & Pickup

    In stock for:

    • Also in stores
    In Limited Stores

     Buy from Marketplace

    Shipping & Additional Information

    Item Description

    The Mongoose Massif 20-Inch Boys' Bike has huge four-inch wide tires that let this fun bike roll over all sorts of obstacles. Twist design shifters allow the rider to change gears quickly and easily through seven speeds assisted by a Shimano rear derailleur. The black/yellow boys' bike features disc brakes that can bring the massive tires to a stop quickly and effectively in most any riding conditions. The aluminum steel frame is both strong and durable and allows young boys to explore their surroundings on a true all-terrain bicycle. The bright yellow alloy rims are lightweight and will ensure that the bike and rider can be seen at all times. The Mongoose Massif 20-Inch Boys' Bike also features yellow handle grips and the familiar Mongoose logo in yellow on the front.

    Please note: If you select Site to Store delivery, your bike(s) will not be assembled upon pickup.

    20" Mongoose Massif Boys' Fat Tire Mountain Bike, Black/Yellow:
    • Frame: Aluminum/steel
    • Mongoose boys' bike gearing: 7 speeds with Shimano rear derailleur for all types of riding
    • Brakes: dual disc brakes provide all-condition braking
    • Tires: super-sized 20" x 4" tires
    • Rims: alloy 4" wide rims for lightweight durability
    • Twist shifters change gears easily
    • 3-piece crank provides added durability
    • Some assembly required
    • Dimensions: 56"L x 27"W x 38"H


    Speeds: 7-Speed
    Bike Type: Boys Bike
    Age End: 11 Years
    Age Start: 6 Years
    Battery Type: Does Not Contain a Battery
    Primary Color: Black
    Multi Pack Indicator: No
    Model No.: R1746WM
    Shipping Weight (in pounds): 46.75
    Product in Inches (L x W x H): 56.0 x 27.0 x 38.0
    Walmart No.: 551828635

    Customer Product Reviews

    Rated 4 out of 5★ by 14reviewers.
    Rated 4 out of 5★ by Needs some adjustments, but good for the cost. I had the bike shipped to my local Walmart where I picked it up. The box was damaged but nothing inside was harmed in any way.Putting it together was easy:I had to put the handlebar assembly into the fork tube. All the cables were on the handlebars and the handlebar was in the stem. You need the proper size hex wrench (allen wrench) to tighten things once installed. I had to rotate the brake levers and shifter around a bit for proper fit. This requires a hex wrench of the proper size.The pedals need to be threaded onto the crank arms. You need the proper size open end wrench or an adjustable wrench to do this. The pedals are clearly labeled as to which goes on the right or left (because of left and right handed threads).The seat and seat post assembly needs slide into the frame, but because the seat post clamp is a quick release, you need no tools to do this. However, the seat pivot nut needs tightened very securely or it will not hold the seat at the angle you set it. Also, a seat frame rod that slides into the back of the plastic seat pan would come out if I picked the bike up by the seat, so I quit picking the bike up by the seat.The front wheel needs put on. The proper sized wrench or an adjustable wrench is required to tighten the axle nuts.At this point the bike was ride-able. However, a couple things needed adjusting. The front brake pads rubbed and made a noise, so I had to adjust the caliper which is easy to do. For more information, check this website on how I set up my bike:http://undergroundvelo.proboards.com/thread/3758/peatbogs-walmart-mongoose-adventurers-wonderlandYou may copy and paste that into your browser if you choose to. I give more information on things than I have space for here.Continuing on, the headset bearings and the bottom bracket bearings were too tight, so I adjusted them. The bike was functional without doing this, but it is better now. It pedals easier and the steering is smoother.Also, I had to adjust the derailleur cable so the the bike would shift through all the gears. This is not unusual with any bike that has to be assembled when you get it. I also needed to use the adjusting screws on the derailleur to keep the chain from falling off the small sprocket as the derailleur moved to far over. These adjustments are relatively easy if you are familiar with them. But if you are not, you may become pretty frustrated trying to get the shifting corrected. If you have problems, find a friendly bike shop (but you will probably have to pay them as they can't stay open working for free) or find a website like the one I listed above where you can ask questions and get the help you need.The seat post is not very long, so if whoever is riding the bike is over about 4'6" or so, you may need a longer seat post. The height I gave there is just a guess. It depends on how you like to have your seat adjusted. However, typical BMX seats are adjusted low, so if you set this up like a BMX bike, it will be fine.This is a cool bike and I am glad I bought it. If you do not know how to adjust the problems I pointed out, you may get aggravated with the bike. But all the parts seems of decent quality and I am very satisfied with the bike for the price I paid. The brakes work well and the gears shifted well once I adjusted things properly. The paint looks good and the bike looks good. The welds on the frame are decent. The decals look to be easily removable if you don't like them.The frame and fork are steel. The Walmart advertising is incorrect in suggesting otherwise. The rims appear to be aluminum, however. Also, there are no training wheels with the bike as suggested in the Walmart advertising.I wish they would have used black hand grips because the orangish-yellow ones will get dirty looking at some point. They do look good now though.Overall, this is a good bike for the money spent. There is nothing else like in a 20" size. If not for the adjustments I needed to make, I would have given the bike a 5-star rating. This bike gets peoples' attention. I hope Walmart makes it in "girl" colors in the future. I like brightly colored bikes for kids as it makes them more visible to those around them. The brightly colored wheels on the present bike are good for that.Presently, I am adding a banana seat and bar, and "apehanger" handlebars to my daughter's Massif. So this is a cool bike for customization also! 03/16/2014
    Rated 5 out of 5★ by Brakes the scale in the "Cool" category This was the center piece at my 10 year old's birthday party. You would have thought that a UFO had just landed in the living room when we revealed it in front of the boys and girls. A stout little bike that glistening with tough attitude. The Caterpillar Yellow rims and accents give it that industrial grade construction site ready feel and the tires look like they were just jacked off a Harley Fat Tail. Everything about this bike says "move over, Boss man is coming through!"Pros: Front and rear disk brakes are awesome once you get them lined up and adjusted (a little tricky for someone who hasn't done it before). Strong construction and heavy duty wheels great for Husky sized young boys. Very smooth and easy to shift gear set. This may be a con for older riders, the twist shiftier has a over sized grip that is great for the little pudgy fingers of the younger kids but hard not to accidentally shift gears (a lot) for larger hands.Cons: Everything about this bike is custom built around the wheel size. The frame, forks and the wheel hubs are non standard in size and may have parts availability issues in the future. Replacement tires are an immediate concern as a fat slick tire and disk brake equal lots of show off power slide to a stop activity in a ten year old.My son wanted a BMX bike, something tough not delicate that he can play rough with. I wanted him to have a geared mountain bike so he could keep up with the rest of the family when we ride. This seems like a good compromise. 06/08/2014
    Rated 5 out of 5★ by The BEST Bike Ever!!! Parents, Grandparents, relatives, etc., if you are thinking about getting your young ones something to have fun with this summer, this is it! I had it delivered to my local Wal-Mart and had it assembled there for free! One note, this bike supposed to come with a training wheels but I never got them when I picked it up the bike after it was put together. Also, the front brake is kinda put together tight because it made a little bit noise (metal rubbing together) but just need to loosen the screw a little. 05/09/2014
    Rated 5 out of 5★ by Fun bike !! Brakes are a little hard to get setup ( nice disk brakes ) , but it's a smooth ride, and great on beach / street terrain. I'm 38 and keep stealing it from my 9 year old / overall 10/10 for price, uniqueness, and functionality. 06/20/2014
    Rated 5 out of 5★ by Fun bike Be sure to understand the disc brake system and how to adjust it! 04/28/2014
    Rated 5 out of 5★ by Fun little bike it gets alot of attention as well Its a bit heavy but i expected that with the fat tires and rims . It shifts well stops well , and is kinda Nimble as i road it around my friends bike shop for fun before going out in the street . For me i added a bigger seat post and may up grade the handle bars later .I already been asked where i have bought it from just with it being in the back of my truck at the convenience store and at a stop light . Over all its a fun and different bike to cruse around with .Id buy another one just because . 03/29/2014
    Rated 5 out of 5★ by coolest bike 8 year old daughter's birthday. De-stickered it. Random compliments everywhere she rides. Easy to assemble and adjust. I went out and got the 'beast' for myself. My 11 year old daughter lowers the seat and rides it. Great cruisers. 06/19/2014
    Rated 4 out of 5★ by Cool bike Cool bike, my 8 year old feels like the coolest kid on the block.Bike seems sturdy made. Easy to put together. Arrived sooner than expected. 07/10/2014
    See All Reviews

    Product Warranty and Service Plan Options

    Product warranty: Limited Lifetime Warranty See details
    Protect it
    Walmart Product Care Plans

    A limited product warranty is included free for most items. With an optional Walmart Care Plan you can enhance the manufacturer's coverage from the date of purchase . Walmart Product Care Plans cover 100% of the cost for repair or replacement, including shipping charges for the exchange.

    We'll show you Care Plan options and pricing at checkout if applicable, or go to www.walmart.com/careplans for more information .

    If you made your purchase in a Walmart store and would like to purchase a warranty Click Here

    Gifting Plans

    Financing Offers

    Make the most of your shopping experience with the Walmart® MasterCard® or Walmart Credit Card.

    Save $25 when you open a Walmart® Credit Card and spend $75 today.*

    *Offer subject to credit approval

    Learn More or Apply Now

    No Payments + No Interest if Paid in Full in 6 Months!
    Enjoy no payments for 6 months. You'll have 6 months with no payments, and no interest if paid in full within 6 months on orders over $250. Otherwise, interest will be charged from the original date of purchase. Bill Me Later is the quick, easy, secure way to buy online without using your credit card. Simply select Bill Me Later at checkout. Subject to credit approval.

    See Terms

    Shipping & Delivery

    Pricing Policy

    About Our Prices

    We strive to provide you with the lowest prices possible on Walmart.com as well as in our stores. However, sometimes a price online does not match the price in a store. Walmart.com's prices may be either higher or lower than local store prices. Prices may also vary between stores. Our local stores do not honor Walmart.com pricing or competitor advertisements from outside of a store's local trade territory.