Introducing the Fly Bikes Proton CST 20 Inch Bike, a sleek red BMX equipped with black handlebars, tires, and pedals. It features a durable CrMo frame and robust tires designed for tricks and stunts. Enjoy its smooth performance thanks to reliable sealed hubs.
The Fly Bikes Proton CST 20 Inch Bike showcases a sleek design when viewed at an angle, featuring a black CrMo frame, high-rise handlebar, large tires, and sealed hubs.
Close-up view of the Fly Bikes Proton CST 20 Inch Bike's wheel, showcasing black pegs attached to the axle, decorative patterns on the fork, and sealed hubs for a smooth ride.
Close-up of the black bicycle seat with stitching and an embossed design, mounted on the CrMo frame of the Fly Bikes Proton CST 20 Inch Bike, perfect for BMX biking enthusiasts.
Close-up of the Fly Bikes Proton CST 20 Inch bike wheel, showcasing black spokes and a silver sealed hub, complete with black axle pegs.
Close-up of the Fly Bikes Proton CST 20 Inch Bike showcasing a black BMX frame with a space-themed design, highlighting the visible chain and tire details. Its durable CrMo frame and sealed hubs provide smooth riding.
Close-up of the front fork and tire of a Fly Bikes Proton CST 20 Inch bike, showcasing a white geometric design on the black CrMo frame's head tube.
Fly Bikes Proton CST 20 Inch Bike in black, showcasing a sleek CrMo frame and large handlebars, set against a dark background.
The Fly Bikes Proton CST 20 Inch Bike, featuring a red frame with black handlebars, sealed hubs, and thick tires, is showcased against a black background.

Description

This sick rig from Fly Bikes is decked with Trebol and Fly Parts to create a shredding machine! This is the Cassette (CST) version. Clickety Clack it pedals when you go back.

PROTON model is the mid-range BMX Bike that performs perfectly on streets but also on ramps. A resistant bike suitable for any purpose a rider could have.

Features
  • Full chromoly frame, fork and bars. Every tube you land on is 4130 CrMo, so the Proton takes street punishment without the weight penalty of Hi-Ten.
  • Cassette rear hub, 9T driver. The sealed bearing Trebol cassette clicks away when you pedal backwards and handles hard cranking out of a roll in.
  • Pegs and hub guards included. A pair of Trebol HS steel pegs and the guards come in the box, so you can grind the day it arrives.
  • 21" top tube, 13.2" chainstay. Street length geometry with a 75° head tube angle: settled enough for ledges, quick enough for ramps.
  • Removable brake mounts. Run the Trebol Springhanger brake or take the mounts off for a clean back end. The bike is 11.9 kg brakeless.

Specifications
  • Size: 20" wheels, 21" top tube
  • Frame: Full 4130 CrMo / removable brake mounts
  • Top tube: 21"
  • Chainstay: 13.2"
  • Head tube angle: 75°
  • Seat tube angle: 71°
  • Standover: 9"
  • Bottom bracket height: 11.75"
  • Fork: Integrated cone shape design / full 4130 CrMo / 1 piece steer tube / 27mm offset
  • Headset: Internal sealed bearing
  • Stem: Trebol top load / forged 6061-T6 aluminium / 50mm
  • Bars: Full 4130 CrMo / 9" rise / 29" wide / 10° backsweep / 2° upsweep
  • Grips: Fly Devon / 160mm long
  • Brakes: Trebol Springhanger / forged 6061-T6 aluminium
  • Brake lever: Generic / forged 6061-T6 aluminium
  • Cranks: Trebol 3 piece / 4130 CrMo / 170mm arm length
  • Bottom bracket: Mid / sealed bearing
  • Sprocket: Trebol / CNC machined / 6061-T6 aluminium / 25T
  • Chain: 510 type / 69 links
  • Pedals: Fly Ruben Graphite / nylon and fibreglass compound
  • Front hub: Trebol male / sealed bearing / 10mm male axle / 36H
  • Rear hub: Trebol male cassette / sealed bearing / 14mm male axle / 36H / 9T
  • Rims: Trebol / semi double walled / 6061-T6 aluminium / 36H
  • Tyres: Fly Fuego 2.30" front and rear / 60 TPI / 120 PSI
  • Seat: Fly Proton Tripod / 100% synthetic leather / 25mm thickness
  • Seat post: Trebol Tripod / forged and CNC machined / 6061-T6 aluminium / 135mm
  • Pegs: Trebol HS steel, 1 pair
  • Weight: 11.9 kg / 26.2 lb (brakeless)
  • Note: Hub guards included. This is the cassette (CST) version.

Assembly information

Your bike ships mostly assembled in the box. Finishing it takes most people 10 to 20 minutes with basic tools, and the video above walks through every step.

  • Fit the handlebars and line them up with the front wheel
  • Fit the front wheel, pedals and seat post
  • Check the brakes and tyre pressure before the first ride

Tools: Allen key set and a 15mm, 17mm or 19mm spanner for the pedals and axle nuts (bikes can vary between these three sizes). A socket is needed if installing pegs.

Rather have it done? Ask us about extra assembly before you order, or any local bike shop can finish the build for a small fee.

Fly Bikes Proton CST 20 Inch Bike

Brand: Fly Bikes SKU:

$1,099.99 AUD

Or 4 payments of $274.99 AUD with

Colour - Flat Red

Top Tube Length - 21

Drive Side - Right Hand Drive

20 inch BMX sizing

A 20 inch bike is the standard adult BMX and suits riders from about 147cm up. At this wheel size the top tube is what changes the fit, so pick that by height.

Rider heightWheel sizeTop tube
60 to 91cm12"12 to 12.5"
81 to 106cm14"14 to 14.5"
96 to 122cm16"16 to 16.5"
122 to 147cm18"18 to 18.5"
147 to 157cm20"19.75 to 20.25"
157 to 168cm20"20 to 20.5"
168 to 175cm20"20.25 to 20.75"
175 to 183cm20"20.5 to 21"
183 to 190cm and up20"20.75 to 21.5"
160cm and up22"21 to 22.25"
160cm and up24"21.75 to 22"
160cm and up26"22 to 23"

Sizes overlap on purpose, so personal preference comes into it. If you land in two bands, riding style breaks the tie: longer for flow, trails and transitions, shorter for technical street and park.

How to measure

Stand your rider against a wall in the shoes they ride in, heels flat, and mark the top of their head. Measure from the floor to the mark.

Top tube is measured from the centre of the seat tube to the centre of the head tube, so it is not the same as the length of the tube you can see.

  • A 20 inch bike is the standard adult BMX and most riders end up there, so do not size a tall child down to a smaller wheel.
  • 22, 24 and 26 inch bikes are adult bikes with a bigger wheel, not bigger frames for taller riders.
  • Size up for stability through trails and transitions. Size down if you want the bike quick and twitchy for spins and grinds.
  • Top tube is fixed, but stem length, fork offset and bar position all shift how roomy the bike feels once you are on it.

Not sure? Send us their height and we will tell you what we would put them on.

Read the full buying guide

20 inch BMX sizing

A 20 inch bike is the standard adult BMX and suits riders from about 147cm up. At this wheel size the top tube is what changes the fit, so pick that by height.

Rider heightWheel sizeTop tube
60 to 91cm12"12 to 12.5"
81 to 106cm14"14 to 14.5"
96 to 122cm16"16 to 16.5"
122 to 147cm18"18 to 18.5"
147 to 157cm20"19.75 to 20.25"
157 to 168cm20"20 to 20.5"
168 to 175cm20"20.25 to 20.75"
175 to 183cm20"20.5 to 21"
183 to 190cm and up20"20.75 to 21.5"
160cm and up22"21 to 22.25"
160cm and up24"21.75 to 22"
160cm and up26"22 to 23"

Sizes overlap on purpose, so personal preference comes into it. If you land in two bands, riding style breaks the tie: longer for flow, trails and transitions, shorter for technical street and park.

How to measure

Stand your rider against a wall in the shoes they ride in, heels flat, and mark the top of their head. Measure from the floor to the mark.

Top tube is measured from the centre of the seat tube to the centre of the head tube, so it is not the same as the length of the tube you can see.

  • A 20 inch bike is the standard adult BMX and most riders end up there, so do not size a tall child down to a smaller wheel.
  • 22, 24 and 26 inch bikes are adult bikes with a bigger wheel, not bigger frames for taller riders.
  • Size up for stability through trails and transitions. Size down if you want the bike quick and twitchy for spins and grinds.
  • Top tube is fixed, but stem length, fork offset and bar position all shift how roomy the bike feels once you are on it.

Not sure? Send us their height and we will tell you what we would put them on.

Read the full buying guide
$1,099.99 AUD

Price match request

Fly Bikes Proton CST 20 Inch Bike - Flat Red / 21 / Right Hand Drive

$12.99 flat-rate shipping Australia-wide

Express from $21.99

Free in-store pickup - Brisbane

Availability

Right Hand DriveLeft Hand Drive
Flat Red
Gloss Black

● In stock at LUXBMX ● With supplier ● Preorder ○ Sold out

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