2021 Fly Neutron Review,

Overview

The Neutron features a lot of upgrades from our Electron model to offer the most complete range possible.

The frame is Trimoly, with 100% CrMo bars and forks that feature the new Volcano inspired design that we are really psyched on.

The tires really stand out on this bike, so we are now including Ruben 2.35” tires and the new Ruben 2 grips to really dial this bike in.

The 2021 Neutron is available in Sierra Forest Green with flat black parts, and Flat Black with the Brown seat that looks great.

RHD: Right Drive Side (Sprocket on the right side)
LHD: Left Drive Side (Sprocket on the left side)

from: fly

Highlights

• ⛔️ - Full Chromoly
• ⛔️ - Under $500
• ✅ - Double Wall Rims - (Double side wall) Not as strong as double wall
• ⛔️ - Pegs
• ✅ - Fully Sealed Bearings
• ✅ - 3 pc. Cranks
• ⛔️ - Freecoaster - What is a freecoaster?
• ✅ - Brakes
• ⛔️ - Gyro tabs
• ⛔️ - 4 pc bars

Key Features

Key Features
Trimoly frame (not full chromoly)
25 lbs
Trebol top load stem
Fly Ruben 2.35" tires

Specs

Price: $540

Colors

• Flat Black
• Flat Forest Green

Specs

FRAME 4130 CRMO DT, TT & CS / 1020 HITEN / 20.75" / REMOVABLE BRAKE MOUNTS

FORK INTEGRATED CONE SHAPE DESIGN / FULL 4130 CRMO / 1 PIECE STEER TUBE / 32MM OFFSET

BARS FULL 4130 CRMO / 9"

GRIPS FLY RUBEN 2 / 160 MM LONG

STEM TREBOL TOP LOAD / FORGED / 6061-T6 ALUMINUM / 50MM

HEADSET TREBOL INTERNAL SEALED BEARING

LEVER TREBOL RIGHT / FORGED / 6061 T-6 ALUMINUM

BRAKE TREBOL SPRINGHANGER / FORGED / 6061 T-6 ALUMINUM

CRANKS TREBOL 3PC / 4130 CRMO / 170MM ARM LENGTH

BOTTOM BRACKET MID / SEALED BEARING

SPROCKET TREBOL / 6061 T-6 ALUMINUM CNC MACHINED / 28T

PEDALS FLY RUBEN GRAPHITE / NYLON - FIBERGLASS COMPOUND

CHAIN 510 TYPE / 74 LINKS

RIMS TREBOL / DOUBLE SIDE WALLED / 6061-T6 ALUMINUM / 36H

FRONT HUB TREBOL BUENO / SEALED BEARING / 3/8” FEMALE AXLE / 36H

REAR HUB TREBOL / SEALED BEARING / 14MM MALE AXLE / 36H / 9T

TIRES FLY RUBEN 2.35 FRONT & REAR / 60 TPI / 110 PSI

SEAT FLY NEUTRON TRIPOD/ 100% SYNTHETIC LEATHER / 7 MM THICKNESS

POST TREBOL TRIPOD / FORGED & CNC MACHINED / 6061-T6 ALUMINUM / 135 MM

WEIGHT 11.35 KG / 25 LB

Frame Geometry

A: Top Tube Length: 20.75″ – Learn what size is right for you here.

This is a medium toptube.

Perfect for riders that are between 5’6″ to 6'3"

Getting a top tube that is taller than suggested will make the bike feel more controlled and less responsive

Getting a top tube size that is smaller than normal will make the bike feel a lot more snappy and responsive.

B: Chain Stay Length: 13.5" – Learn About Chain Stays Here

This is a long chainstay.

A long chain stay will make the bike feel controlled.

A short chain stay makes the bike feel twitchy. Spins will be easy, but airing and jumping might feel hard to control.

A long chain stay will make the bike feel really controlled. Spins will feel sluggish, but manuals and air tricks will feel nice because it will be more stable.

C: Head Tube Angle: 75° – Learn About Head Tube Angles Here

Steep head tube angles make the bike “snappy” meaning more responsive to fast turns.

A less steep head tube gives you more control.

D: Seat Tube Angle: 71°

E: Bottom Bracket Height: 11.75″

F: Stand over height: 9.25″

This is a tall standover.

A tall standover gives the bike a responsive and snappy feeling. Good for barspins and controlled riding.

Bar Geometry - Learn more here

G: Rise: 9″

Riding a tall rise, will give you more leverage on the bike. Making it easier to pull back and lift the front wheel up.

H: Width: 29″

This is a medium width.

Narrow bars make barspins easier.

Wide bars give you more control and stability when steering.

I: Backsweep: 10º

What does backsweep do?

As far as I know, there is a sweet spot for backsweep. Too much will make the bike feel weird, and too little will make the bike unstable. It seems like the sweet spot is around 11º to 12º. If you need something a little more aggressive and straight feeling, go for 10º, but only do this if 11º is uncomfortable.

J: Upsweep: 2º

This is a normal upsweep!

What does upsweep do?

There is a lot of discussion about 1º upsweep vs. 4º upsweep. Some people are running experiments and testing if the greater upsweep will make drops feel better. It seems like a lot of street riders run 4º to 5º upsweep. This helps for wrist pain and lessens the impact of big drops.

Price

So I actually don't really recommend this bike. But it isn't because it is low quality, it's actually decent quality for a beginner bike. The thing is, that the bike is overpriced.

You can get a comparable quality bike like the Kink Gap for much less than $540.

Quality

The 2021 Neutron will last good for a beginner rider. But for a mid to high-level rider, you will be breaking parts left and right.

The biggest thing that concerns me is the trimoly frame. One time, I had a trimoly frame, and as I was learning 360's the back end of my frame started to bend from constant impact.

Buy if you are learning:

• no-handers
• 360 taps
• bar spins
• small grinds
• Tire-taps
• turndowns

Don't buy if you are learning:

• Big drops
• big spins
• back flips
• grinding hand rails

Conclusion

The Neutron is best for a beginner rider. It has enough quality to last while you learn some beginner tricks, but not while you do big tricks. I would recommend looking at other beginner or mid-level bikes to ensure you make the right purchase.

With that being said, Fly is a really good brand who has a lot of support. and if you love Fly and are riding at a beginner level, the Neutron will fit good for you. Just make sure you have enough money.

Common Questions

• Where can I buy this bike? As an affiliate for sourcebmx.com, I always recommend them. They have a warehouse in the USA so shipping is pretty fast and they do so much to support bmx. Buy it here
• Is this bike for park, dirt, or street? It is a well-rounded bike that will do good on all park, street, and dirt.
• How much does it weigh? 25 lbs