Mongoose Legion L40

Mongoose’s Legion L40 is the sweet-spot BMX in the range. It’s extremely good value for riders - especially for teens and pre-teens - who are often searching for their first proper BMX.

Mongoose has used a high-tensile (or Hi-Ten) steel for the main frame and fork. A high-tensile steel is used for the Legion L40 because it’s part of a group of performance steels. This means better corrosion resistance, lighter and can handle way more stress.

The Legion L40 frame has a 20.5-inch top tube.

It’s worth noting that all Legion BMX’s (except for the L16 and L18) have 20-inch wheels. It’s the OG wheel size; present since Day 0.

The models differ in the components - and the top tube length.

And the top tube length is (one of) the things that matter. It’s how long or short a BMX is. 20.5-inches is a good “average” size. As a rough estimate, we’d recommend the 20.5” top tube for riders between 152cm to 168cm.

Yes, BMX’s are simple (especially compared to a mountain bike) but parts for key areas still needs to be thought about.

One area is the bottom bracket.

It’s under tremendous load - always. It’s where you apply pressure to the pedal and where you apply power.

The Legion L40’s mid-sealed bottom bracket features sealed bearings. These are going to be resistant to the elements and therefore last longer, especially compared to the bottom brackets on the Legion L10 and Legion L20.

Rims tend to be the other area.

The L40 build uses a 36-hole wheel for extra strength. Plus the rim’s 24mm width paired to 2.30-inch wide tyres means it can handle impacts and has less chance of pinch flatting. The wide rim also adds extra strength.

Upgrade from Legion L20

0.25-inch longer in the top tube (20.5” top tube).
Better Mid-sealed bottom bracket (details below).

Key Features

20.5” top tube length. Suggested rider height is 152cm-168cm.
Hi-Ten steel frame and mid BB shell.
Drivetrain features 175 mm 3-piece tubular chromoly hollow spindle cranks with a 25T steel chainring and mid sealed bearing bottom bracket.
20” x 2.3” tyres mounted on aluminium single wall 36H rims with 3/8” in axle front hub and 9T cog sealed bearing cassette rear hub.
Hi-Ten steel handlebar and fork, 50 mm stem, standard 1-1/8” headset, and aluminium U-brake and brake levers.

SPECIFICATIONS

Size	20.50-inch Top Tube
Frame	Hi-Ten steel, BMX freestyle geometry, mid BB shell
Fork	Hi-Ten steel steerer and fork
Crank	3-piece, tubular chromoly, 25T steel chainring
Chain	KMC S1
Bottom Bracket	Mid sealed bearing, 8-spline spindle
Cassette	Single-speed, 9T cassette driver
Rims	Aluminium single wall, 24mm ID, 36H
Hubs	[F] Steel, ball bearing, 3/8" axle, 36H [R] Steel, sealed-bearing cassette, 14mm axle, 36H
Spokes	14G, steel, black
Tyres	20"x2.30", wire bead
Pedals	Mongoose, nylons
Brakes	U-brake, aluminium
Handlebar	Hi-Ten steel, 28" width, 8" rise
Stem	Mongoose, threadless top load, 50mm
Headset	Threadless, integrated 1-1/8”, cartridge bearing
Seat Post	Steel, 250mm, 25.4mm
Saddle	Mongoose Unifier
Grips	Mongoose Mush XL, 160mm

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