20" Mongoose Boys' Massif fAT bIKE

Wide-tire bicycles with flotation are great in snow or on sand.
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20" Mongoose Boys' Massif fAT bIKE

Postby desertguns » Sat Mar 01, 2014 5:26 am

http://www.walmart.com/ip/20-Mongoose-B ... w/29741122

So a boys 7 speed fat bike comes out before the long awaited adult version. This is pretty cool for a kid's bike.

Image
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Re: 20" Mongoose Boys' Massif fAT bIKE

Postby Peatbog » Sat Mar 01, 2014 4:21 pm

I have one on order. Today I received an email from Walmart that it is on the way to the local Walmart now. :P
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Re: 20" Mongoose Boys' Massif fAT bIKE

Postby desertguns » Sun Mar 02, 2014 8:25 am

Peatbog wrote:I have one on order. Today I received an email from Walmart that it is on the way to the local Walmart now. :P

Please let us know what you think. Wondering how those 20" lunar lander tires really feel at 10-12 psi. I'd be interested in seat tube to head tube measurement & if you think it could handle 230 lbs. 8-) There might be unique potential for adult uses.
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Re: 20" Mongoose Boys' Massif fAT bIKE

Postby Falkon45 » Sun Mar 02, 2014 2:29 pm

I want this bike!

Actually, I want this for my son, and the larger version for me. But, I'd have to sell one of the others to justify buying it... damnit all! I should just sell my corolla to make up for two more bikes.
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Re: 20" Mongoose Boys' Massif fAT bIKE

Postby 7up » Tue Mar 04, 2014 5:08 am

I can go for one as well. :D
Panasonic DX1000
Nishiki Manitoba (Japan) 1000w48v
Specialized Comp Stump Jumper
Dahon Formula S18
Mongoose Beast * Brutus * Dolonite * Massif ......Like they say "Once You Go Fat........."
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Re: 20" Mongoose Boys' Massif fAT bIKE

Postby 7up » Tue Mar 04, 2014 6:29 pm

I couldn't help it but I bit the bullet and just ordered one for myself.It will be ready for pickup next Thursday.Im 5'8" 227 lbs.I have envisioned a sort of 60-70's look.Hi-rise black bmx handlebars.Black banana seat and long sissy bar in back.Should look good.What do you guys think?
Panasonic DX1000
Nishiki Manitoba (Japan) 1000w48v
Specialized Comp Stump Jumper
Dahon Formula S18
Mongoose Beast * Brutus * Dolonite * Massif ......Like they say "Once You Go Fat........."
7up
 
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Joined: Fri Feb 21, 2014 3:19 pm

Re: 20" Mongoose Boys' Massif fAT bIKE

Postby tigris99 » Tue Mar 04, 2014 11:15 pm

I'm planning on getting one for my son for Xmas provided I can figure out tires that have actual traction. I can shave weight off it easily but he's gonna want to snow ride with me when I get my fatty.

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Re: 20" Mongoose Boys' Massif fAT bIKE

Postby Peatbog » Sun Mar 09, 2014 8:29 am

I bought a Walmart Mongoose Massif 20" for my nine-year-old daughter:

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I picked the bike up yesterday from Walmart and put it together. I had plans to tear it apart, paint it metallic blue, put on a chrome chainwheel, handlebars, stem, sissybar, seatpost, and cranks; add a banana seat and change the black spokes to shiny stainless, but the kid says she likes it as it is, so I will leave it that way for now. I will probably put taller handlebars on it though.

It was an easy assembly out of the box:

1. All the cables were on and the handlebar was in the stem, but the stem needed to be placed in the fork. You need the correct size hex wrench to loosen the "wedge" and then to tighten it again once in the headtube. You also have to adjust the handlebar as it needs rotated in the stem. The brake levers and twist grip need spun around also so as to be at a good angle to fit whoever's hands will be riding the bike. All of these adjustments require correct sized metric hex (Allen) wrenches.

2. The pedals need installed. Each pedal and each crank arm have left/right stickers so it would be hard to be confused as to the right and left hand thread situation. You need the correct size open end wrench or an adjustable wrench to tighten the pedals.

3. The seat is on the seatpost but the seatpost needs put in. The seat post clamp is a quick release so this is easy. The seat clamp is kind of crappy though, but it works. You really have to crank down on the bolts to keep the seat from spinning on the post. To adjust the seat angle, you need a wrench or socket of the correct size, or an adjustment wrench.

4. The front wheel needs put on. Again, easy enough with a wrench, socket or adjustable wrench.

5. The front and rear reflectors needs adjusted to face correctly. This is done with a Phillips-head screwdriver. I moved the front reflector from the right to left hand side of the handlebars where it did not interfere with the cables as much. There are two reflectors on the rear--one on each side that clamp to the seat stays. On the brake side, the reflector interferes with the brake cable and so just does not really fit right, so I took that one off. The wheel reflectors have the most elaborate mountings I have ever seen on wheel reflectors. If you want to take them off, you need a Phillips-head screwdriver.

Things I needed to adjust (headset bearing adjustment, derailleur adjustment, front brake adjustment):

1. The headset bearings were too tight. It wasn't terrible, but it was tight enough to be a bit notchy. This was easy to fix by loosening the lock nut and the adjustment nut and tightening the lock nut back down. You need the correct sized open end wrench or a large adjustable wrench to do this. I didn't check how much grease was in the bearings because I wanted to just get the thing together.

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Loosen top nut and adjust knurled nut below.

2. The derailleur would not shift the chain to the big gear. This is because the cable needed tightened as it was too slack to have enough pull to move the derailleur in far enough. There is an adjuster on the twist grip and at the derailleur, but I adjusted the cable at the derailleur by loosening the cable clamp and pulling it through a bit more. You need the correct wrench, socket, or an adjustable wrench to do this. You can probably tighten the cable plenty by just using the two adjustment screws available. Then I used the adjuster at the twist grip for fine tuning.

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Loosen cable clamp nut, pull cable through a bit more to adjust derailleur.
You can see the cable adjustment screw here also.


Image
Tapered cylinder is the derailleur cable adjustment nut.

3. The front brake was dragging. This was an easy enough fix also. There are two socket head cap screws facing rearward on the brake caliper. Loosen them with a hex wrench and move the brake caliper in or out (toward or away from the wheel) until the brake pads have clearance on either side of the brake disc. The holes are slotted to allow for this side to side movement. I don't really know anything about disc brakes, but just looking at the set-up, a person should be able to figure this out if not afraid to just try something. Heck, if something isn't working correctly, you can't screw it up because it already is, so try something. It appears there is an adjustment on the back of the brake caliper to tighten the clearance between the brake pads too, but I didn't need to do that, so I did not try. Both of these adjustments take the appropriate sized metric hex wrench.

Image
Mongoose Massif front disc brake adjustment.
Brake adjustment screws allow brake caliper to slide side to side to eliminate brake drag.
This is the rear brake, but the front is the same.


The adjustment of the bottom bracket bearings seemed fine. I did not take it apart to check for grease. The rear brake was adjusted fine. Both brakes work well. Shifting seems to work well also. However, this is all without actually riding the bike, as I put it together in my living room as ice pelts down outside. I have no intention of freezing my kid for a test run.

Oh, the wording in the Walmart ad may lead some to believe training wheels come with the bike. They don't. The Walmart website also states: "Frame: aluminum/steel". However, the frame is steel as is the fork, stem, handlebars, and seatpost. I am not sure where the aluminum is lurking. The wheels appear to be aluminum however.

This is a small bike. The top tube length is short. From the center of the top of the head tube in a horizontal line back to the center of the seat post is about 18-1/2". I really doubt it would work well for anyone much larger than my nine-year-old. If you look at it like a BMX bike instead of a mountain bike, the size won't seem as small. However, a banana seat would help because it would move the seating position back to give more room. The seat post is extended about as far as it can be in the picture above, so if you need it longer, you will need to buy a different seat post.

Overall, I would say this is a pretty decent bike for the price. I am happy with it. The components seem adequate, and the build quality is decent. The only thing that would worry me would be a strong or heavy rider possibly bending the long crank shaft. But for my daughter, this thing should work fine for a very long time. Here is the biggest problem with this mini-fat bike: It is cute so other, larger children in your family will think they need a fat bike too, but the fat bike they need will need to be bigger and so cost you more money. So at the onset of fat bikedom, you must set a limit to how many fat bikes are allowed in your household.
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Re: 20" Mongoose Boys' Massif fAT bIKE

Postby desertguns » Sun Mar 09, 2014 9:27 am

Excellent write-up, Mr. Bog! Yeah, the Wally description of the Massif & Dolomite lead you to believe you'll get an aluminum frame & steel fork. Or at least that's what I gathered from, "Frame: Aluminum/Steel".

Wondering if 20 x 4 tires really have much flotation & do you run them at 8-10 psi like the 26" counterparts?
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Re: 20" Mongoose Boys' Massif fAT bIKE

Postby Peatbog » Mon Mar 10, 2014 6:22 pm

Got a torch and a vise, starting a sissy bar. Gonna need it if I'm putting a banana seat on it.

Image
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