The Fit Bike Co PRK 20 Inch Bike, a maroon BMX park bike with a short top tube, black tires, black seat, and handlebars, is displayed on a white background.

The Fit Bike Co PRK 20 Inch Bike is a blue BMX park bike featuring a short top tube, black tires, silver spokes, black handlebars, and red brake cables, shown on a white background.

Close-up of the Fit Bike Co PRK 20 Inch Bike, highlighting its maroon frame, headset, stem, brake cables with gyro for barspins, and part of the handlebar.

Close-up of the Fit Bike Co PRK 20 Inch Bike’s blue handlebars, headset, and stem with red cables, a gyro for barspins, and a geometric red decal on the short top tube.

Close-up of a crankset, chainring, and black pedal on a blue Fit Bike Co PRK 20 Inch BMX with "FITBIKECO" text and a short top tube.

Description

The PRK starts with a frame and fork built specifically for transition park riding. It runs a slightly shorter 12.6" rear end, a low 7.25" standover and a more relaxed 75.3 degree head angle than FIT's all-round S1 geometry, which adds up to more control and flow on ramps.

The custom PRK fork has a responsive 25mm offset, peg clearance cutouts and a longer 172mm steerer tube so a gyro can go on for barspins. Two top tube lengths are offered, 20" and 20.5", each paired with 8.7" bars and its own crank length, and the build includes a Pivotal seat, an alloy sprocket and a double wall rear wheel.

Features

Park geometry for shorter riders. A low 7.25" standover and a short top tube let smaller riders move around the bike in transition.
12.6" rear end, 75.3° head angle. Shorter and more relaxed than FIT's all-round S1 geometry, which gives you more control and flow in the park.
Gyro ready 172mm steerer tube. The longer steerer and gyro holes in the head tube mean you can run a detangler for barspins.
Fork with 25mm offset, peg cuts. Responsive up front, with clearance cut into the legs for when you want to put pegs on.
Two sizes with matched parts. Pick a 20" or 20.5" top tube: each comes with 8.7" bars and cranks to suit, 160mm or 165mm.

Specifications

Size: 20"
Frame: Cro-Mo front triangle, park geometry
Top tube: 20" or 20.5"
Chainstay: 12.6"
Head tube angle: 75.3°
Standover: 7.25"
Fork: Cro-Mo steerer, tapered legs with peg cuts, 25mm offset, 172mm steerer, welded insert
Headset: Integrated with gyro holes
Stem: FIT top load
Bars: 2-piece, 8.7" x 29"
Brakes: U-brake with low tension springs, linear cable
Brake lever: Two finger
Cranks: Tubular Cro-Mo, 160mm on 20" top tube, 165mm on 20.5"
Bottom bracket: Sealed mid
Sprocket: FIT alloy Key 25T
Pedals: FIT PC
Front hub: Sealed
Rear hub: Sealed 9T cassette
Rims: FIT S1W front, double wall rear
Seat: FIT Pivotal
Seat post: 200mm

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.

Fit Bike Co PRK 20 Inch Bike

Name: Fit Bike Co PRK 20 Inch Bike
Brand: Fit Bike Co
SKU: FTBK113-26-PLM
Price: 1099.99 AUD
Availability: InStock

Brand: Fit Bike Co SKU: Click to copy the SKU and show the pick location

$1,099.99 AUD

Or 4 payments of $274.99 AUD with

Colour - Plum

Top Tube Length - 20

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 height	Wheel size	Top tube
60 to 91cm	12"	12 to 12.5"
81 to 106cm	14"	14 to 14.5"
96 to 122cm	16"	16 to 16.5"
122 to 147cm	18"	18 to 18.5"
147 to 157cm	20"	19.75 to 20.25"
157 to 168cm	20"	20 to 20.5"
168 to 175cm	20"	20.25 to 20.75"
175 to 183cm	20"	20.5 to 21"
183 to 190cm and up	20"	20.75 to 21.5"
160cm and up	22"	21 to 22.25"
160cm and up	24"	21.75 to 22"
160cm and up	26"	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