Mongoose Boy’s Legion L40 BMX Bike Review

Mongoose Boys Legion L40 BMX Bike Review

The combination of components and design make this bike a great entry for kids who we are serious about BMX freestyle, and want to do more than just ride around.

Pros Gearing setup, U-Brakes, rotating hub
Cons Weight
Summary The combination of components and design make this bike a great entry for kids who we are serious about BMX freestyle, and want to do more than just ride around.
Our Rating 92/100
Manufacturer Mongoose

In many cases, it will cost a hefty amount of money to get a true freestyle BMX bike that has everything needed to immediately hit the vert, park course, or streets. If you’re buying a bike for a young boy, it can be a little hard convincing yourself to put money into a bike he may not be able to ride in a year or two.

The Mongoose Boy’s Legion L40 BMX Bike makes it easy and affordable to purchase a legit boy’s freestyle bike that goes beyond the gimmicks and aggressive appearance, and delivers a quality level of riding that is suitable for kids who are just getting into freestyle, or have already gotten started.

The Legion L40 not only includes the necessary components for freestyle riding, it combines quality parts and detailed engineering that delivers a riding experience that is on par with adult-sized freestyle BMX bikes.

If you’re thinking that this is going to cost you more than it should, we’ve got good news. The Legion L40 is available for under $200, making it one of the best BMX values out there in terms of real freestyle bikes for kids.

Introducing the Mongoose Boy’s Legion L40

FRAME: Steel

BREAKSET: Full Alloy 2-finger

SHIFTERS: 21-speed SRAM grip shifters

MEASUREMENTS: 22.83 x 7.87 x 48.42 inches

TIRES: 36 spoke black alloy wheels

EXTRA FEATURES: 4 axle pegs

Like we said earlier, it can sometimes be hard to differentiate between phony freestyle BMX bikes for kids, and legitimate ones that can actually be used for the demanding conditions of true freestyle riding.

This is especially true for big box stores that push cheaper bikes that have all the right looks, but lack any actual substance, quality parts, or craftsmanship. While most people aren’t going to go out and buy some expensive BMX bike for their kid, they at least want one that’s actually more than just a novelty bike.

Legion L40 review

The Legion L40 fills that niche, giving parents a very affordable option that utilizes true freestyle engineering and parts, resulting in a bike that can ensure years of riding in a variety of freestyle formats, or just casual riding around the driveway and neighborhood.

The Legion L40’s foundation is its steel frame. The frame isn’t the lightest you’ll see, but it isn’t overly heavy either. When the bike is fully assembled, the total weight sits around 37 lbs. While some may think that’s too heavy, we don’t think so.

It may be too heavy for adult riders, but younger boys who are still getting the hang of true freestyle will be just fine from the weight, and enjoy an added sense of stability as well, which is actually more beneficial.

The drivetrain of the Legion L40 shows that it means business. The 25/9 cassette setup with smaller sprocket provides an ideal gear ratio for freestyle riding, focusing on short bursts of speed needed when trying to get sufficient air in limited space.

The smaller sprocket ensures a higher ground clearance as well. A 3-piece tubular pair of crank tubes is used on the Legion L40, alongside alloy pedals that offer a better sense of durability, especially in the event of crashes.

Like most quality freestyle bikes, the Legion L40 has front and rear U-brakes, along with a rotating hub in the front to prevent tangled cables, while allowing worry-free handlebar spins.

The wheelset features an all-black look, which we’re always in favor of. 36 spoke alloy wheels are included, along with smooth freestyle-oriented tires that utilize a tread for pavement riding. Pegs are installed on the front and rear hubs, making the Legion L40 ready for grinds, stalls, and more.

In terms of a freestyle bike, it’s hard to think of anything that’s been left off, regardless of age level.

What We Like

The Legion L40 has a lot of aspects that caught our attention.

The gearing setup is perfect for freestyle riding, which includes both the actual ratio, and the ground clearance provided by the smaller sprocket. You don’t always get that with boy’s BMX bikes, especially for this price.

The rotating hub is never a guarantee either for entry-level BMX bikes. Handlebar spins are now largely considered a basic trick, so it’s helpful to have a bike that can easily handle that.

U-brakes are always preferred over linear brakes on a freestyle bike, so we are glad to see them used on the Legion L40. The alloy pedals are a nice touch as well, and a solid upgrade over the usual plastic ones.

What We Don’t Like

While we don’t think the weight of the bike is a huge issue, it wouldn’t hurt if if it was a few lbs lighter. Boys who are just starting out may have a hard time getting air when they are first learning how to jump.

Buying Advice

Amazon almost always has the lowest price on Mongoose BMX bikes, so it’s best to order from them. Do realize that the bike does not come fully assembled by default, but you will receive instructions on how to finish the assembly once it arrives.

For those who are willing to pay the extra price, you can elect to have the bike fully assembled before it’s shipped, saving you some time and hassle in the process, and ensuring a BMX bike that is ready to ride the moment it arrives at your home.

Mongoose Legion L40 review


The Legion L40 is a very impressive bike through and through, and not just because it’s an above-average boy’s BMX bike. The combination of components and design make this bike a great entry for kids who we are serious about BMX freestyle, and want to do more than just ride around.

The Legion L40 is built to take the same punishment doled out to adult freestyle bikes, and comes with all the necessary features that are conducive to true street and park riding.

From its gearing, to its pegs, to its wheelset, the Legion L40 holds its own in the freestyle world, and is the most economical way to ensure a suitable BMX bike for jumps, grinds, spins, and also casual rides.

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