How To Build A Complete Bike
How To Build Your BMX Bike
Most of our complete bikes arrive around 90% built to keep the box small and shipping safe. Here's exactly how to finish the job yourself in well under half an hour, tools included.
Shop Complete Bikes Jump To The StepsWhat You'll Need
Nothing specialist — if you've got a basic toolkit at home you're probably already sorted.
Tools Checklist
- Track pump
- 17mm socket or spanner
- 5mm Allen key
- 6mm Allen key
- Pedal spanner (15mm)
- 10mm spanner
- Grease
- A clean cloth
Missing anything? Browse our tools range.
9 Steps To Your First Ride
Work through these in order and take your time — there's no rush, and a properly tightened bike is a safer one.
Unbox Carefully
Lift the bike out of the box and free any parts that are cable-tied to the frame for transit. Cut away only the packaging covering bolts and fixing points — it's worth leaving the rest wrapped around the frame and forks until you're finished, since it's free protection against scuffs while you're working on it.
Fit The Front Wheel
Complete bikes ship with the front wheel off to keep the box smaller. Check which way the tread on the rear tyre points, then fit the front wheel so it's spinning in the same direction, and tighten both axle nuts securely with your 17mm socket or spanner.
Fit The Seat & Post
Slide the seatpost into the frame and set a height and angle you're happy with for now — you can always fine-tune it once you're riding. The one thing that matters here: the post needs to be inserted at least as far as the minimum-insertion line marked on it. Ride with it above that line and you risk cracking the frame.
Straighten & Set The Stem
Loosen the stem's rear bolts with your 6mm Allen key and twist the stem until it's square with the front wheel. Tighten the headset top cap just until any slack disappears but the forks still spin freely, then tighten the stem's rear bolts to lock everything in place.
Fit The Bars
Remove the front plate from the stem, drop the bars into place, and refit the plate — just tight enough to hold the bars without you needing to hold them yourself. Before going any further, check the plate sits level and the knurled (roughened) section in the middle of the bars is centred in the stem.
Tighten The Bars Evenly
Once the bars are angled where you want them, work around the four stem bolts a little at a time in a criss-cross pattern rather than fully tightening one before moving to the next. This spreads the clamping force evenly across all four bolts instead of loading up just one.
Fit The Pedals
Lightly grease the threads, then fit the pedals into the crank arms. Pedals and cranks are marked L and R and only go one way — if a pedal won't thread in by hand, stop; it's either on the wrong side or cross-threaded. Only reach for your pedal spanner once it's already done up finger-tight.
Inflate The Tyres
Pump both tyres up to a pressure you're comfortable with, without going over the maximum PSI printed on the tyre's sidewall.
Final Check
Peel off the rest of the packaging, then go over every bolt and nut on the bike before your first ride — wheels, stem, bars, seat clamp and pedals. Give everything a firm tug; if nothing moves, you're ready to go.
A Few Extra Tips
Do I need to torque everything to a specific number?
Most home mechanics get by on feel rather than a torque wrench — tight enough that nothing shifts when you push or twist it by hand, without forcing it. If you do have a torque wrench, the settings are usually printed in the manual that comes with the bike.
What if a bolt won't tighten properly?
Stop and don't force it — a stripped thread is much harder to fix than a five-minute phone call. Get in touch and we'll talk you through it or sort a replacement part.
How often should I recheck the bolts once I'm riding?
Give the whole bike a quick once-over after your first few rides, since a brand-new bike can settle slightly as everything beds in. After that, a monthly check is a good habit — especially the headset, stem and seat clamp.
Would you rather just build it for us?
Of course — get in touch and we can talk through build options.
Ready To Ride?
New to BMX altogether? Our buyer's guide covers riding styles, sizing and what to look for before you buy.