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

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.

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 .

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-wonderland You 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!

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.

The rear derailleur ended up in the spokes shortly after just a couple rides and bent the frame. After sending pictures of the issue to the manufacturer, they kindly replaced the bike. The exact same 2nd bike arrived in a box and was assembled once again. Then on a 2nd ride, and a new bike, the rear derailleur ended up in the spokes again, but this time it didn't bend the frame. I took both bikes to my local bike shop for inspection and discovered that the rear derailleurs were bent. However, after attempting to replace on derailleur and then doing a test ride, the front fork broke! The bike mechanic looked at the 2nd bike and discovered that the fork on this was bent as well. So, two bikes with the exact same issue and risk. After contacting the manufacturer, they have offered to replace once again with a different model. So, I have to say that they are trying to make amends for what seems to be a poor product. However, I'm really concerned that these bikes could have quality issues that could be a safety risk.