---
product_id: 148969896
title: "Mongoose Legion Kids Freestyle Sidewalk BMX Bike"
brand: "mongoose"
price: "$1380.50"
currency: USD
in_stock: true
reviews_count: 13
category: "Mongoose"
url: https://www.desertcart.us/products/148969896-mongoose-legion-kids-freestyle-sidewalk-bmx-bike
store_origin: US
region: United States of America
---

# 20-inch full-size BMX wheels 2.3-inch wide tires for confident grip 9T alloy rear hub for responsive acceleration Mongoose Legion Kids Freestyle Sidewalk BMX Bike

**Brand:** mongoose
**Price:** $1380.50
**Availability:** ✅ In Stock

## Summary

> 🚀 Own the streets and skateparks with the Mongoose Legion — where every ride is a progression.

## Quick Answers

- **What is this?** Mongoose Legion Kids Freestyle Sidewalk BMX Bike by mongoose
- **How much does it cost?** $1380.50 with free shipping
- **Is it available?** Yes, in stock and ready to ship
- **Where can I buy it?** [www.desertcart.us](https://www.desertcart.us/products/148969896-mongoose-legion-kids-freestyle-sidewalk-bmx-bike)

## Best For

- mongoose enthusiasts

## Why This Product

- Trusted mongoose brand quality
- Free international shipping included
- Worldwide delivery with tracking
- 15-day hassle-free returns

## Key Features

- • **Wide-Grip Tires:** 2.3-inch tires deliver unmatched traction on pavement, dirt, and park surfaces—stay planted while pushing limits.
- • **Durable 1-Piece Crank:** Smooth, reliable pedaling that builds strength and balance through every stage of BMX progression.
- • **Authentic BMX Geometry:** Designed for riders 5'3" to 6'0" to master street and skatepark skills with pro-level control.
- • **Legacy of Limit-Pushing:** From BMX pioneers Mongoose, 50+ years of action sports expertise packed into every ride.
- • **Responsive Alloy U-Brakes:** Dependable stopping power that lets you dial back speed safely without sacrificing style or control.

## Overview

The Mongoose Legion L10 is a youth freestyle BMX bike featuring full-size 20-inch wheels, wide 2.3-inch tires, and authentic BMX geometry tailored for riders between 5'3" and 6'0". Built with a durable 1-piece crank and a 9T alloy rear hub, it offers smooth pedaling and responsive acceleration. Alloy U-brakes provide reliable stopping power, making it perfect for street riding and skatepark sessions. Backed by Mongoose’s 50+ years of BMX heritage, this bike is engineered for confident progression and skill-building.

## Description

The Mongoose Legion L10 is a freestyle BMX bike built for riders ready to take the next step into BMX. Featuring full-size 20-inch wheels, true BMX geometry, and durable components designed for street riding, skatepark sessions, and everyday progression, the L10 delivers the control and responsiveness riders need to build confidence. Wide 2.3-inch BMX tires provide grip on pavement, packed dirt, and skatepark surfaces, while the durable 1-piece crank keeps pedaling smooth and reliable. The 9T alloy rear hub delivers authentic BMX gearing and a responsive ride feel, while the alloy U-brake provides dependable stopping power when it's time to dial things back. As one of the OGs in BMX and action sports, Mongoose has spent more than 50 years helping riders push limits, learn new tricks, and discover what BMX is all about. The Legion Series delivers freestyle BMX bikes for every stage of progression, from first-time riders to dedicated park and street riders. We've always been about epic rides and pushing limits—and we're just getting started.

Review: Extremely Easy to Assemble. Bike Looks Amazing. M8x1.25 Tap May be Needed. - The bike from the pictures looked pretty cool. I didn't realize how beautiful this bike would be until it came in the mail. I purchased the Legion Mag in orange for my 8 year old. It was great to see his reaction on Christmas when receiving this bike. He was so excited. I read some other reviews from reviewers who had complaints on the difficulty of assembling the bike and in my opinion the people having trouble assembling the bike must be blatantly ignorant or illiterate. The instructions for assembly are written so a teenager could assemble this bike, with clearly labeled diagrams and more in depth explanations than what is necessary for assembly. The instructions on assembly are excellent and I had almost no trouble assembling the bike without them until it came to adjusting the brakes. I assembled the entire bike without instructions except for the brakes because it is just self explanatory. I was also able to assemble the brakes without any trouble or needing the instructions although I did refer to them for proper adjustment and alignment protocols. The only issue I had when assembling the bike is when I got to the point of attaching the handlebars to the handlebar binder assembly attached to the stem. The four socket cap screws that tighten down on the handlebar binder bracket would not thread easily. I felt as though I would break the screws or destroy the threads if I attempted to tighten them down far enough to grip the handlebars. There was too much paint in the threaded holes and also the tolerances on the machining of the threads was not great. I have included some pictures showing just how much paint was removed from tapping and also chips from burs in the threaded holes from poor tolerance drilling and tapping at the factory. In order to fix this problem I grabbed a tap handle and a M8x1.25 normal thread tap and tapped the holes. I would give this bike a 4.9 out of 5 if I could just because I needed to tap these holes and a tap was not listed as a required tool. I don't think many people will have problems assembling the bike even if they have this issue and need to tap the four holes as these are the only holes that need anything to be screwed into. Honestly if you don't at the very least know how to use a tap and die set you probably shouldn't be assembling a bike as it's not safe to do so if you're not familiar with basic tools. You could wind up hurting your child from pure negligence if you don't know how to use basic hand tools to assemble this bike properly. My suggestion is that you take it to a local bike shop and pay $30-$40 to have them assemble the bike and adjust the brakes if you don't know what you are doing. I assume some people who buy this bike will do just that with the majority of people knowing how basic hand tools work and them being able to assemble it themselves. Overall the bike is amazing, my son loves it, it was extremely easy to assemble, and I recommend you tap the holes on the handlebar binder even if it doesn't need it as it will allow you to make a more secure connection. Please don't listen to people complaining about difficult assembly as it was extremely easy even the detangler brakes something of which I've never seen or dealt with on a bike before. The instructions are very clear on how to hook the brakes up and how to adjust them properly and I was actually surprised how easy it was to assemble the brakes because I was expecting something very difficult based on the reviews but it turns out these brakes are easier to assemble than normal brakes.
Review: GREAT BIKE! HIGHLY RECOMMEND. - I assembled it today and it took 20 minutes tops. If you have ever assembled anything before then it should be fairly easy. I didn't open the manual for instructions besides confirming my suspicion of which direction the large washers with the raised ridge were orientated. The raised edge goes inwards towards the forks FYI. The brakes were very easy to adjust, I seen reviews stating how difficult they were to adjust or setup. Not sure why but they couldn't be a more basic setup. I also recommend making sure the bearings in the fork tube are not to tight. The ones on the bike I received were WAY to tight and you could physically feel individual bearings moving when you turned the handlebars. After adjusting accordingly it moves nice and smooth. I saw a review that their stalk broke and this could be why it broke. If they are to tight you can damage them and eventually the stalk as well. I definitely recommend this kids freestyle bike. Brings back memories of my bmx bikes back in the 80's. The orange color is awesome as well. Especially since my grandson is a big Oregon State beavers fan.

## Features

- FIRST REAL BMX: Designed for riders 5'3" to 6'0" tall, this freestyle bike combines full-size 20-inch wheels and authentic BMX geometry for progression on the street and at the skatepark.
- CONFIDENT GRIP: Wide 2.3-inch tires provide confident traction on pavement, park surfaces, and packed dirt. Built to help riders stay planted while building skills and trying something new.
- BUILT FOR PROGRESSION: A durable 1-piece crank helps keep pedaling smooth and reliable while developing strength, balance, and bike control through every stage of learning.
- TRUE BMX FEEL: A 9T alloy rear hub pairs with BMX-specific gearing for responsive acceleration and a ride feel that's right at home on jumps, transitions, and neighborhood sessions. Alloy U-brakes provide dependable stopping power.
- KNOW YOUR ROOTS: As one of the OGs in action sports, Mongoose has helped bring the BMX movement to the world. For over 50 years, we've been all about epic rides and pushing limits – and we're just getting started.

## Technical Specifications

| Specification | Value |
|---------------|-------|
| ASIN | B0H7TBHHR8 |
| Additional Features | Adjustable Seat |
| Age Range (Description) | Youth |
| Age Range Description | Youth |
| Best Sellers Rank | #43,923 in Sports & Outdoors ( See Top 100 in Sports & Outdoors ) #67 in Kids' Bicycles |
| Bicycle Drivetrain Type | Chain Drive |
| Bike Type | BMX Bike, Kids Bike |
| Brake Style | U Brake |
| Brand | Mongoose |
| Brand Name | Mongoose |
| Color | Grey |
| Customer Reviews | 4.4 out of 5 stars 4,024 Reviews |
| Derailleur Configuration | Rear |
| Frame Material Type | High Tensile Steel |
| Included Components | Reflectors, User Manual |
| Intended Riding Terrain | BMX Terrain, Paved Roads, Urban Terrain |
| Item Type Name | BMX Bicycle |
| Item Weight | 28.6 pounds |
| Manufacturer | Mongoose |
| Maximum Weight Recommendation | 200 pounds |
| Minimum User Height | 48 inches |
| Model Name | Legion L10 |
| Model Number | M4136G27U2OS11 |
| Model Year | 2026 |
| Number Of Speeds | 1 |
| Number of Speeds | 1 |
| Power Source | Manual |
| Seat Material | Polyvinyl Chloride (PVC) |
| Size | 20-Inch Wheels/L10 |
| Specific Uses For Product | Freestyle |
| Suspension Type | Rigid |
| UPC | 038675293724 |
| Unit Count | 1 Count |
| Warranty Description | Limited lifetime warranty on frame. 1 year limited warranty on parts. 30 day limited warranty on wearable parts. |
| Warranty Type | Limited |
| Wheel Material | Aluminum |
| Wheel Size | 20 inches |
| Wheel Width | 2.35 inches |

## Product Details

- **Age Range (Description):** Youth
- **Bike Type:** BMX Bike, Kids Bike
- **Brand:** Mongoose
- **Color:** Gray
- **Frame Material:** High Tensile Steel
- **Included Components:** Reflectors, User Manual
- **Number of Speeds:** 1
- **Special Feature:** Adjustable Seat
- **Suspension Type:** Rigid
- **Wheel Size:** 20 inches

## Images

![Mongoose Legion Kids Freestyle Sidewalk BMX Bike - Image 1](https://m.media-amazon.com/images/I/81YSsVr4GEL.jpg)
![Mongoose Legion Kids Freestyle Sidewalk BMX Bike - Image 2](https://m.media-amazon.com/images/I/71LjXh2QacL.jpg)
![Mongoose Legion Kids Freestyle Sidewalk BMX Bike - Image 3](https://m.media-amazon.com/images/I/71fjk5CvXKL.jpg)
![Mongoose Legion Kids Freestyle Sidewalk BMX Bike - Image 4](https://m.media-amazon.com/images/I/81wzxI7bQmL.jpg)
![Mongoose Legion Kids Freestyle Sidewalk BMX Bike - Image 5](https://m.media-amazon.com/images/I/81nkhYBZlCL.jpg)

## Available Options

This product comes in different **Color, Size** options.

## Customer Reviews

### ⭐⭐⭐⭐⭐ Extremely Easy to Assemble. Bike Looks Amazing. M8x1.25 Tap May be Needed.
*by D***E on December 30, 2020*

The bike from the pictures looked pretty cool. I didn't realize how beautiful this bike would be until it came in the mail. I purchased the Legion Mag in orange for my 8 year old. It was great to see his reaction on Christmas when receiving this bike. He was so excited. I read some other reviews from reviewers who had complaints on the difficulty of assembling the bike and in my opinion the people having trouble assembling the bike must be blatantly ignorant or illiterate. The instructions for assembly are written so a teenager could assemble this bike, with clearly labeled diagrams and more in depth explanations than what is necessary for assembly. The instructions on assembly are excellent and I had almost no trouble assembling the bike without them until it came to adjusting the brakes. I assembled the entire bike without instructions except for the brakes because it is just self explanatory. I was also able to assemble the brakes without any trouble or needing the instructions although I did refer to them for proper adjustment and alignment protocols. The only issue I had when assembling the bike is when I got to the point of attaching the handlebars to the handlebar binder assembly attached to the stem. The four socket cap screws that tighten down on the handlebar binder bracket would not thread easily. I felt as though I would break the screws or destroy the threads if I attempted to tighten them down far enough to grip the handlebars. There was too much paint in the threaded holes and also the tolerances on the machining of the threads was not great. I have included some pictures showing just how much paint was removed from tapping and also chips from burs in the threaded holes from poor tolerance drilling and tapping at the factory. In order to fix this problem I grabbed a tap handle and a M8x1.25 normal thread tap and tapped the holes. I would give this bike a 4.9 out of 5 if I could just because I needed to tap these holes and a tap was not listed as a required tool. I don't think many people will have problems assembling the bike even if they have this issue and need to tap the four holes as these are the only holes that need anything to be screwed into. Honestly if you don't at the very least know how to use a tap and die set you probably shouldn't be assembling a bike as it's not safe to do so if you're not familiar with basic tools. You could wind up hurting your child from pure negligence if you don't know how to use basic hand tools to assemble this bike properly. My suggestion is that you take it to a local bike shop and pay $30-$40 to have them assemble the bike and adjust the brakes if you don't know what you are doing. I assume some people who buy this bike will do just that with the majority of people knowing how basic hand tools work and them being able to assemble it themselves. Overall the bike is amazing, my son loves it, it was extremely easy to assemble, and I recommend you tap the holes on the handlebar binder even if it doesn't need it as it will allow you to make a more secure connection. Please don't listen to people complaining about difficult assembly as it was extremely easy even the detangler brakes something of which I've never seen or dealt with on a bike before. The instructions are very clear on how to hook the brakes up and how to adjust them properly and I was actually surprised how easy it was to assemble the brakes because I was expecting something very difficult based on the reviews but it turns out these brakes are easier to assemble than normal brakes.

### ⭐⭐⭐⭐⭐ GREAT BIKE! HIGHLY RECOMMEND.
*by B***Y on September 1, 2026*

I assembled it today and it took 20 minutes tops. If you have ever assembled anything before then it should be fairly easy. I didn't open the manual for instructions besides confirming my suspicion of which direction the large washers with the raised ridge were orientated. The raised edge goes inwards towards the forks FYI. The brakes were very easy to adjust, I seen reviews stating how difficult they were to adjust or setup. Not sure why but they couldn't be a more basic setup. I also recommend making sure the bearings in the fork tube are not to tight. The ones on the bike I received were WAY to tight and you could physically feel individual bearings moving when you turned the handlebars. After adjusting accordingly it moves nice and smooth. I saw a review that their stalk broke and this could be why it broke. If they are to tight you can damage them and eventually the stalk as well. I definitely recommend this kids freestyle bike. Brings back memories of my bmx bikes back in the 80's. The orange color is awesome as well. Especially since my grandson is a big Oregon State beavers fan.

### ⭐⭐⭐⭐⭐ Amazing Color!!!
*by B***S on September 1, 2026*

Great product, my son is happy. It just remains to try it on the street.

## Frequently Bought Together

- Mongoose Legion Kids Freestyle Sidewalk BMX Bike, Beginner Riders, Boys and Girls, 16-20-inch Wheels, Hi-Ten Steel Frame, Micro Drive BMX Gearing
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- Mongoose Legion Kids Freestyle BMX Bike, Intermediate Rider, Boys and Girls Bikes, 20-Inch Wheels, Hi-Ten Steel Frame, Micro Drive 25x9T BMX Gearing

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*Product available on Desertcart United States of America*
*Store origin: US*
*Last updated: 2026-09-15*