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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Availability:
In Stock.
Arrives
Sep 5 – Sep 15
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Color: Copper
Size: 20-Inch Wheels/L40
Features
- L40 is a fully park, street or dirt-worthy freestyle BMX bike that offers everything a new rider could need to bust their first tricks on their local ramp! Suggested rider height is 50-56
- Durable bike, built with a Hi-Ten steel frame, removable brake mounts, and a mid BB shell, and has a top tube length of 20.5"
- Equipped with a high-performance drivetrain that includes 175 mm 3-piece tubular chromoly hollow spindle cranks, a 25T steel chainring, and a mid-sealed bearing bottom bracket
- Wheelset featuring 20" x 2.3" tires mounted on 36H aluminum single-wall rims, along with a 3/8" female axle front hub and a 9T cog sealed bearing cassette rear hub
- Aluminum U-brake and brake levers provide precision speed control, while the Hi-Ten steel handlebar and fork are joined by a 50 mm stem and threadless sealed integrated headset for maximum steering performance
Description
For 45 years, Mongoose has been in the dirt, down the trails, and on the ramps. With the Legion Series, Mongoose offers a full line of freestyle BMX bikes for riders of all ages and ability levels. The Legion L20 was designed to be a fully park, street and dirt worthy BMX bike. The Legion L20 features a Hi-Ten steel frame (20.25” top tube), tapered headtube, and removable brake mounts. The L20 Hi-Ten steel 8” rise handlebar and 48mm stem are designed for precision riding, while the wide aluminum single wall 36H rims and 2.3” BMX tires offer grip and durability. The 25x9T gearing with one-piece tubular chromoly 170mm hollow spindle cranks and American loose ball bottom bracket offer a clean, reliable drivetrains. An alloy U-brake with alloy brake levers provide speed control, while the Hi-Ten Steel BMX fork with 1-1/8" threadless steerer and taper leg helps maximize performance. This bike ships ready to be assembled and comes with a 5-year limited warranty on the frame and a 1-year limited warranty on parts.
Bike Type: BMX Bike
Age Range (Description): Big Kid
Brand: Mongoose
Number of Speeds: 1
Color: Copper
Wheel Size: 20 inches
Frame Material: High Tensile Steel
Suspension Type: Rigid
Special Feature: Aluminum Frame, BMX, freestyle
Included Components: Mongoose Legion L40 Freestyle BMX Bike
Bike Type: BMX Bike
Number Of Speeds: 1
Suspension Type: Rigid
Additional Features: Aluminum Frame, BMX, freestyle
Brake Style: U Brake
Specific Uses For Product: Trail
Power Source: Pedal power
Skill Level: Intermediate
Gear Type: cassette
Intended Riding Terrain: BMX Terrain
Bicycle Drivetrain Type: Single-speed
Number of Handles: 2
Color: Copper
Theme: BMX
Style Name: Bmx
Wheel Size: 20 inches
Size: 20-Inch Wheels/L40
Item Weight: 12 kg
Warranty Type: Limited
Minimum User Height: 60 inches
Age Range Description: Big Kid
Brand Name: Mongoose
Included Components: Mongoose Legion L40 Freestyle BMX Bike
Model Number: M41500U20OS-PC
Model Name: Legion Intermediate
Model Year: 2020
Global Trade Identification Number: 46
UPC: 038675187146
Manufacturer: Pacific Cycle, Inc.
Unit Count: 1 Count
Item Type Name: BMX Freestyle Bike
Warranty Description: 5-year limited warranty on the frame and a 1-year limited warranty on parts.
Frame Material Type: High Tensile Steel
Wheel Material: Aluminum
Seat Material: Nylon
Frequently asked questions
If you place your order now, the estimated arrival date for this product is:
Sep 5 – Sep 15
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.
To initiate a return, please visit our Returns Center.
View our full returns policy here.
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Top Amazon Reviews
Color: Orange
Size: 20-Inch Wheels/MAG
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.
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Reviewed in the United States on December 30, 2020 by Dave
Color: Silver/L18
Size: 18-Inch Wheels/L18
My son, absolutely loved this bike when he received it, and it was put together, the bike was perfect for his size. It rode very smooth and I feel like I got what I paid for unfortunately after moving into our new place, the bike was stolen from our backyard
Reviewed in the United States on May 29, 2026 by Latisha
Color: Red
Size: 20-Inch Wheels/L20
All you need are some tools, a brain, some patience and reasonable expectations for this to be put together and on the road. If you have half a brain and basic tools, you’re going to be able to put this together without even looking at the instructions. This will come in a box, front tire packaged off. It comes with no tools, everything zip tied so it could remain intact on the long trip from CHIIIINA to the US. Packaging is solid. There are several thick zip ties to cut to break everything loose. You’re going to need: Metric hex tools A 15 and 18 mm socket for axels 15mm wrench or socket to tighten handlebar alignment Scissors or utility knife for zip ties Phillips screwdriver (for the reflectors only) You’ll need an extension bar to remove the nuts from the axels to install the pegs on front and back. Will take you about 60 seconds to do this. Front handlebars install with hex keys. Honestly not sure how anybody could have problems with this. It’s four bolts. Secure them, and you’re good. But man, some reviewers couldn’t figure this out. Install the seat with another hex socket. Put on the reflectors, hook up the brake, fill the tires with air, and you’re riding. Btw, the factory purposefully ships tires with less air than you’ll need for your benefit. Any tire sitting for an extended period will last longer if not fully inflated. Hooking up the brake is a bit of a pain in the A, as you won’t have enough slack in the front to properly attach the cable unless you briefly disconnect the rear brakes. Once you pull the cable through in the front to attach, reattach the rear. Took me a minute to figure this out. The front break setup is such that you can spin the handlebars around to 1) look cool, and 2) not have the brake line get wound around the front of the bike. The bike is good, solid and worth the money. Assembly, with any mechanical skill (even entry level mechanical skill) will take 20 minutes. Also, warning: you’re buying a $200 bike. It will last like a $200 bike. Many people on here complain about the quality. This isn’t a $1000 bike. Don’t pretend it is. Take care of it, don’t beat it to death and you’ll be good. If this was at all helpful, please hit the button.
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Reviewed in the United States on December 21, 2020 by HolyShoot
Color: Red
Size: 20-Inch Wheels/L20
< Overall > So first off, this is a decent bike. Having twin boys this has all the cool features that they didn't even know they looking for (that's because these were features I was looking for at their age); free wheel, spinny handlebars, foot pegs, and a cool color scheme. I've read some reviews of this bike on other, bike-oriented sites that pick apart certain mechanical aspects of this bike and I must say people sure seem to expect a lot for this price point. From my perspective--and having grown up with a Huffy--this is about the nicest bike I could imagine having as a kid. < Assembly > Having twin boys meant that I got to experience assembly twice. Which is the reason I deducted a star from the bike, the assembly manual is generic and meant to cover several versions of these bikes. As such it does every version of the bike a disservice by not actually explaining things very well or at all in the case of the brake cable installation for the L20. There isn't a lot to the assembly. The main frame and all the components are already installed. You just have to put on the front wheel, mount the handlebars to the stem, install the seat, pedals, foot pegs (if you even want them), and finally attach the brake cable to the brake lever. Having a metric socket set and Allen key set are essential. < ASSEMBLY NOTE: Attaching the Brake Cable > I've seen more than a few reviews here decrying the assembly of the brake cable with folks going so far as to return the bike, buy additional parts, or dump it off at the bike shop. Let me say I understand your struggle. However, I did figure out how to install the cable without needing to go that route and it was actually pretty easy. The cable, as it turns out, is the right length, but I found it necessary to disassemble the brake lever and remove it in order to make it work. I takes the 4mm allen key to remove the screw. The lever components include two plastic bushings on either side of the lever and a spring. Pay careful attention to how these parts come out, because reassembly is the same. Once the lever is off and the brake cable is fed through the lever mount, you can line up the cable and the barrel in the hole on the lever and rotate it into place. Now you'll actually have enough leverage to easily re-seat the lever arm although it will require a modicum of coordination to make sure all the parts stay on the arm until you can get them back into the handle-bar mount. I don't know if I explained that well, I'm not even sure if that was the easiest way to do this, but it worked reliably for me. < FINAL NOTE: Test! > Once everything is assembled, test the bike. I cannot stress this enough. Don't assume that because it's all been assembled it's ready to go. The manual itself makes a big point of this as well.
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Reviewed in the United States on October 6, 2020 by Ajax
Color: Orange
Size: 20-Inch Wheels/MAG
Great Bike for a beginner and a leap above Huffy and Walmart bikes. I remember Mongoose being a Good recognizable brand decades ago. This bike was easy to assemble. I think it took an hour to unbox and put together. Box was damaged heavily, but bike was packed so well with foam and wrapping that there wasn't a single scratch. The most important part is the kid is happily surprised and liked the color.
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Reviewed in the United States on March 2, 2026 by The Real Hughleys
This Legion L20 is the third Mongoose BMX bike I've purchased over the last year, and I've been very happy with all three (Legion LSX, Title Pro, and L20). Assembly was very easy on all three bikes; just need to attach the front wheel, handle bars, and pedals. Took only about 15 mins. You just need to pay attention to the direction of the forks and remember the left pedal will be left-hand threaded. The forks and pedals have stickers denoting front/rear, left/right. Besides adjusting for height and putting air in the tires, there really wasn't any need for fine adjustments (chain tension, brakes, misc. nuts, etc.), as these things are being adjusted correctly from the factory (nice surprise). After reading the negative reviews on this bike and the others mentioned, it seems many of them are related to incorrect user assembly. If you put the forks on backwards or don't put air in the tire, you're going to have problems. The Legion L20 is reasonably light at roughly 25 lbs., easy to ride, and looks great. Note, however, that this is a freestyle bike, and probably not the best choice if you're just looking for a neighborhood cruiser. The crank bracket sits about 1" higher than on a race type BMX bike, making the apex pedal feel too high when in a sitting position. This may not bother some people. If it does, you could buy shorter cranks, but with the money you'd spend, it would be more logical to just go with a race style bike with the lower bracket (and larger front sprocket). The Title series with a lengthened seat post makes for a great lightweight cruiser. Not much to complain about on this bike. Excellent quality for the money. If you're looking for a reasonably priced freestyle bike with good quality, at $156, this is a great choice.
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Reviewed in the United States on October 24, 2020 by Anonymous
Color: Orange
Size: 20-Inch Wheels/MAG
With all of the four and five star ratings, I must be the problem, right? The bike came partially dissembled for shipping purposes. I expected that. What I did not expect was: 1. Missing parts. One of the nuts and both of the washers were missing from the front wheel. Ok. A shipping problem. But what kind of washers do I need to go find? Should be simple. Just read the instructions. 2. Horrible Instructions: For example, to attach the front wheel, I need to follow the appropriate set of instructions depending if my bike's wheel is, "nutted with step retaining washer, nutted with clip retaining washer or quick release". But I don't know which one my bike is; the nut and both washers are missing. Every section is just like this; follow the set of instructions that pertain to your bike. But where does it say if the bike I purchased has a quill stem, a threadless stem, a front load stem or a top load stem? I have no idea. Mongoose has been around for a while. So there are plenty of videos on YouTube. But there are so many configurations for Mongoose bikes, good luck finding the right one. I watched a bunch of videos, went to Wal-Mart (twice) and got $30 worth of nuts, washers, hex drivers and, no I didn't go out and buy the lithium gel they recommended! Then I paid a bike shop $45 to put the thing together because I still couldn't figure it out. The bike shop wouldn't do the brakes because of liability purposes. But they showed me that I needed to loosen a nut and put the brake cable out some. Should be easy, except... 3. CHEAP parts!: I stripped a nut and two screws trying to tighten the brakes just enough to barely work. It's Christmas Eve and I'm soooo frustrated. Should I be worried? Every single step in the instruction book says that if I don't do this step correctly, someone could get seriously injured or killed. Here ya' go son. Have fun! Merry Christmas. I could call Mongoose Customer Support. They are open Monday through Friday 8 to 5; because that's when dads assemble bikes right? Sorry for all of the venting. I've had the bike for a week and I have to say, I have NEVER had this much trouble assembling something that came in a box. I've got $250 invested into a $170 bike and I don't feel safe letting my son ride it. I am not a happy customer.
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Reviewed in the United States on December 25, 2020 by Jared D.
Color: Red
Size: 20-Inch Wheels/L20
Received the bike within a week. Assembly difficulty was medium-low. The instruction manual was more general for all Mongoose BMX bikes. The simple order of assembly was: handlebars, brake, seat, wheel, pedals, pegs, (F&R) reflectors. Previous reviews claimed the brake line was a pain to install. Found out the hard way was to install the line into the handbrake right before mounting the handlebar. After everything was installed, i inspected the bike and tightened as necessary. The axel nuts were different sizes in the front and rear and pegs were properly sized for each. The brakes did require adjusting. I used a Park Tool 4th Hand. The tires needed a little bit of air for the recommend 40 psi. Both tires out of box were in the 30s. My son had no problem with this bike. He is 10yo and about 4’9”. This was not his first hand brake so no issues there. His previous bike was an 18” with coasters and hand brakes. He said this bike seems heavy but rides very smoothly. His only complaint is the whistling from the hollow stem bolt while he rides. I have even taken his bike for a few spins and it’s the perfect size and weight for your basic tricks and jumps. I did add a children’s Bell adjustable kickstand but doesn’t appear to last much longer. We want the kickstand because he’s always parking in the garage by the cars and doesn’t like the bike just laying on its pegs. Any questions, please feel free.
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Reviewed in the United States on May 31, 2020 by Amazon Customer