The Stay Strong V5.1 Junior Race Bike is an orange and black BMX race bike with a straight top tube, black handlebars, and thin tires, featuring a lightweight aluminium frame, photographed on a white background.
The Stay Strong V5.1 Junior Race Bike features a lightweight aluminium junior disc frame in white and orange, complemented by black wheels, flat pedals, and straight handlebars, and is displayed against a white background.
Close-up of the Stay Strong V5.1 Junior Race Bike's black front fork with "S2X" logo, highlighting the spokes and a section of a CYCLOPRANE tire against a white background. The lightweight aluminium construction reflects its purpose-built design for speed and agility in BMX racing.
Close-up view of a lightweight aluminium wheel on the Stay Strong V5.1 Junior Race Bike, featuring black spokes, a hub with "SD" branding, and part of a black fork—details that highlight the bike’s precision engineering designed for BMX racing.
Close-up of the Stay Strong V5.1 Junior Race Bike rear wheel hub, highlighting the disc brake rotor, caliper, spokes, and chain on its lightweight red and white aluminium frame.
Close-up of the black handlebars of the Stay Strong V5.1 Junior Race Bike, featuring a "STAY STRONG" logo, visible handle grips, brake lever, and a section of the aluminium frame against a white background.
Close-up of the Stay Strong V5.1 Junior Race Bike handlebar featuring a gray textured grip and black brake lever against a white background, highlighting the lightweight aluminium construction.
Close-up of a black handlebar and stem with bold white "STAY STRONG" branding, crafted from lightweight aluminium, featured on the Stay Strong V5.1 Junior Race Bike against a plain white background. Perfect for upgrading any BMX race bike or junior disc frame.
Close-up of the Stay Strong V5.1 Junior Race Bike's black BMX handlebar featuring a textured grip and Tektro brake lever, set against a white background to highlight its lightweight aluminium construction, ideal for junior disc frame setups.
Close-up of the Stay Strong V5.1 Junior Race Bike’s rear wheel featuring the disc brake, black caliper, chain, and part of its red and white aluminium frame.
Close-up of a Stay Strong V5.1 Junior Race Bike, featuring an aluminium frame with orange and white graphics, partially displaying the text "STI BIKE" and "FOR LIFE," as well as showcasing the tire, chain, and disc brake in the background.
The Stay Strong V5.1 Junior Race Bike, featuring a white and orange aluminium frame, black handlebars, black tires, and a single gear, is shown on a white background.

Description

From the hundreds of conversations, and all the custom bike builds we've done over the years, there's one thing we've learned, and that's the confusion that parents encounter when deciding on the spec of a build for their young rider. This Stay Strong is what we would build if our junior rider was moving up from a off-the-foor race bike onto something more highly tuned, a little lighter and more responsive than a entry level race rig.

We ain't busting the budget neither with this one and keeping it sensible with a aluminium frame as opposed to a carbon frame. Let little Johnny prove his chops a little more before throwing him into the deep end with a carbon build, he's still probably in sprockets after all on this sized bike.

What little Johnny will love though is the dual character pain scheme of the Stay Strong V5.1 frame. Mum and dad won't miss him either on the bright orange and white bike, a real standout. 

We haven't scrimped on the spec though, with a whole bunch of Stay Strong and SD components bolted to the frame to produce a real weapon of a junior race bike. Touches like the SD B-85 cranks and SD CNC'd chainring means that this bike is well elevated above a stock floor bike. 

Like we mentioned, we've had plenty of experience building custom race bikes and with this junior Stay Strong we've done all the heavy lifting for you, and saved the confusion of deciding how to spec out a bike. Add it to the cart, this bike is built ready to ship or pick up in store. 

Features
  • Aluminium frame, sensible money. The Stay Strong V5.1 Junior disc frame sits well above an off-the-floor race bike without pushing you into a carbon build.
  • SD carbon fork up front. An SD Expert 20 inch 10mm carbon fork takes weight off the front end of the bike.
  • SD B-85 cranks and CNC chainring. 145mm cranks with a CNC'd 6061 40T chainring on an SD Euro bottom bracket, geared 40 x 16 for 50.98".
  • Bengal disc brake kit. Stay Strong's Bengal disc setup on an SD Ace 2 disc rear hub gives a junior rider consistent stopping power.
  • 7.86 kg, built and ready. Reactiv-2 rims, Tioga Powerblock tyres and a dual character orange and white paint scheme, ready to ship or pick up in store.

Specifications
  • Size: 20" wheels, 18.5" top tube
  • Frame: Stay Strong V5.1 Junior Disc, aluminium
  • Top tube: 18.5"
  • Fork: SD Expert 20 Inch 10mm carbon, black
  • Headset: Stay Strong Icon
  • Stem: Stay Strong Top Line V2 Race, 45mm
  • Bars: Stay Strong 4.5 Inch alloy
  • Grips: ODI x Stay Strong Reactiv V2.1, grey
  • Brakes: Stay Strong Bengal disc brake kit
  • Cranks: SD B-85, matt black, 145mm
  • Bottom bracket: SD Euro BB
  • Chainring: SD CNC 6061, 40T, with alloy chainring bolts
  • Chain: KMC K1 SL Race
  • Pedals: Stay Strong Pivot Junior platform
  • Front hub: SD Ace 2, 10mm
  • Rear hub: SD Ace 2 Disc, 10mm
  • Rear cog: 16T alloy
  • Spokes: Spectre T302 SB Sandvik 14G, black
  • Rims: Stay Strong Reactiv-2, 28 hole, front and rear
  • Tyres: Tioga Powerblock 20 x 1-1/8
  • Seat: Stay Strong Fast Chevron plastic Pivotal
  • Seat post: 22.2mm Pivotal alloy
  • Seat clamp: SD 25.4mm alloy
  • Gearing: 40 x 16, 50.98"
  • Weight: 7.86 kg
  • Colour: Bright orange and white

Assembly information

Your race 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
  • Spin the rear wheel and check the rotor runs clear of the calliper
  • Check the brake and tyre pressure before the first ride

Disc brakes: keep your fingers off the rotor and pads, because oil from your skin contaminates the braking surface and takes the bite away. If the rotor rubs, loosen the two calliper bolts, squeeze the lever, then tighten them again with the lever held on. Bed the brake in with a few firm stops before you race it.

Tools: Allen key set and a 15mm spanner for the pedals. Check your axle hardware, since race bikes vary between bolt-on nuts and a thru-axle.

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.

Stay Strong V5.1 Junior Race Bike

Brand: Stay Strong SKU:

$4,499.99 AUD

Or 4 payments of $1,124.99 AUD with

Colour - Orange/ Black

Top Tube Length - 18.5

BMX race bike sizing

Race frames are sized by class, and the class you ride is set by rider height rather than age.

SizeRider heightTop tube
Micro (18" wheels)Under 120cm16.25"
Mini (20" wheels)110 to 140cm17 to 18"
Junior120 to 150cm18.25 to 18.75"
Expert130 to 170cm19.5 to 19.75"
Expert XL145 to 170cm20 to 20.75"
Pro150 to 175cm20.25 to 20.75"
Pro XL165 to 180cm21 to 21.25"
Pro XXL170 to 185cm and up21.5 to 21.85"
Pro XXXL175cm and up22"
Pro XXXXL180cm and up22.5"
Cruiser (24" wheels)175cm and up21.5" and up

Heights overlap between classes on purpose. Where you land in two, a growing rider is usually better on the larger, and a rider who wants the bike to turn faster on the smaller. Some brands label the Pro size Pro L, with the same fit.

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.

  • Between two sizes and still growing? Take the larger size.
  • Racing gates and wanting the bike to turn faster? Take the smaller size.
  • Top tube is the number that actually changes the fit, so compare it against the bike they ride now.

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

Read the full buying guide

BMX race bike sizing

Race frames are sized by class, and the class you ride is set by rider height rather than age.

SizeRider heightTop tube
Micro (18" wheels)Under 120cm16.25"
Mini (20" wheels)110 to 140cm17 to 18"
Junior120 to 150cm18.25 to 18.75"
Expert130 to 170cm19.5 to 19.75"
Expert XL145 to 170cm20 to 20.75"
Pro150 to 175cm20.25 to 20.75"
Pro XL165 to 180cm21 to 21.25"
Pro XXL170 to 185cm and up21.5 to 21.85"
Pro XXXL175cm and up22"
Pro XXXXL180cm and up22.5"
Cruiser (24" wheels)175cm and up21.5" and up

Heights overlap between classes on purpose. Where you land in two, a growing rider is usually better on the larger, and a rider who wants the bike to turn faster on the smaller. Some brands label the Pro size Pro L, with the same fit.

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.

  • Between two sizes and still growing? Take the larger size.
  • Racing gates and wanting the bike to turn faster? Take the smaller size.
  • Top tube is the number that actually changes the fit, so compare it against the bike they ride now.

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

Read the full buying guide
$4,499.99 AUD

Price match request

Stay Strong V5.1 Junior Race Bike - Orange/ Black / 18.5

Metro bike shipping from $59.99

Regional and remote rates may differ

Free in-store pickup - Brisbane

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