How to build an adult bike

Here at Halfords we wanted to show you How to build your boxed bike, our expert will talk you through the tools you will need and the steps you need to follow.

What you’ll need

Before you get started, make sure you’ve got all the right tools, you will need:

  • Small phillips and flat head screwdrivers
  • Bike Grease
  • Allen keys
  • Wire cutters
  • Spanners and sockets 9-15mm
  • Spanners and sockets 9-15mm
  • You can build a bike without a bike stand but if you like the look of the one on screen you’ll find it here Bikehut repair stand

If you’re missing anything, you can easily order everything on this list.

Shop Bike Building Tools

Step by step guide

Get the bike out of the box

Be careful of the staples they can be very sharp! Remove the loose parts, the saddle and the peddle box, put these to one side until you need them. 

Top Tip Take a note of your frame number after you have moved the bike in the box, it is usually 2 letters followed by a series of numbers underneath the bike where the pedal arms come into the centre of the frame.  This number is unique to your bike so a great way for it be traced.

Remove all the packaging

Carefully cut all the cable ties and remove all the packaging, remember to recycle all you can.  Be careful not to scratch the paintwork or nick the tyres.

Fitting the saddle

Start by greasing the seat post and slide it into place in the seat tube. Don't worry about getting the height right just yet; you can set it later. At this stage, you just need to have it fitted.

Fitting the handlebars

Remove the face plate, lift the handlebars into place making sure you don’t twist the cables, check the logos on the brakes and gears are facing up, a good sign you have them on the right way!  Reattach the face plate. Check the handlebars are nice and central.

Check controls

Tighten the brakes and the gear levers. Make sure the bell and reflector and in place and tighten so they don’t move.

Top Tip Be careful not to over tighten and crack the plastic.

Tighten Headset

Tighten the top headset so the handlebars still move freely without any rocking movement. Lock this all place with the bolts of the side of the stem.

Fitting the front wheel

First use the pump to inflate the tyres. Check the sidewall of the tyre for a guideline on the right air pressure. It's important not to under- or over-inflate the tyres. Grease the axle making sure you don’t get anything on the disc, fit the axle following the instructions and attach the wheel to the bike, this is easiest with the bike upside down.

Fit the pedals

Install each pedal on the correct side of the bike, pedals are marked L for left and R for right. We recommend using a 15mm pedal spanner to tighten them thoroughly. Note: Left hand pedals have a reverse screw thread, to tighten turn the pedal anti-clockwise.

Check the crank bolts

Tighten them on both sides to ensure the pedals stay connected to the bike. Ideally you should use a torque wrench to set these bolts to 40-45nm

Check the gears

Tighten the top headset so the handlebars still move freely without any rocking movement. Lock this all place with the bolts of the side of the stem.

Read our detailed guide and watch a video on how to adjust gears on a mountain bike.

Final safety checks

Check there are no kinks in the cables and that the cable is sat in the cable guides.

Ensure that front-wheel turn freely by lifting it off the ground and giving it a few spins.

Press and release the brake levers to check they're working making sure to squeeze them sharply to check the cables don’t slip.

Watch a video guide on how to adjust mechanical disc brakes.

If you need any additional help, specifically with brakes and gears, check out our Cycling Help & Advice for a wealth of information.