A step by step method of building a child's bike safely.
I was passing a bike shop and I saw this clever piece of advertising pointing out how difficult it is to assemble a bike ordered online.
I see internet bikes like this in public bike racks ; the parents have assembled them incorrectly.
I've seen forks put on backwards, pedals forced into the wrong crank, pads rubbing the tyres and many other things that make a bike dangerous.
Mostly, cheap children's bikes are atrociously made and that in conjunction with bad assembly makes a child's first riding experience a bit less enjoyable than it should be.
It's not hard to assemble them correctly but if you are not a cyclist yourself, it can be confusing.
Sometimes a friend will ask me to build up a bike for them or rebuild one that they have tried to -assemble . . . here is such a case.
In this Instructable I will try show step by step the process of building a bike safely for your children.
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Step 1: Tools
By law , tools have to be supplied.
This is what you get.
Take the supplied spanner and walk to your re-cycling bin and return it to it's maker; it will only cause you pain and frustration.
The Allen key supplied will usually do the job.
You will need a:
6mm Allen key
5mm Allen key
Big screwdriver ( old one) and a hammer
Headset spanner or adjustable wrench.
Step 2: Freeing the Beast.
Pull the top opening apart ( watch out , there are sharp staples ).
Pull the bike out.
Cut all the zipties off.
Pull the front wheel gently away from the bike; it will have the crank pushed through its spokes so slide it off this.
Pull all the packing off ( this can be recycled.)
Step 3: The Saddle.
The saddle is usually on its own in the box.
Undo the saddle clamp bolts a touch and pull the seat post into an upright position and re-tighten the bolts.
Fit this into the bike and tighten the seat post bolt.
I am using a bike stand so I have temporarily left the seat very high.
On the seat post there will be a serrated marking telling you that the post should not go any higher; this is for safety reasons but very easy to miss the marking.
Step 4: The Tyres.
The tyres will have a pressure rating on the side.
Pump your tyres up to this pressure using the gauge on your pump ( if you have no pump them just do it hard enough so that your determined thumb will not compress the tyre)
Step 5: The Handlebars
It's best to get the handlebars in now.
Important- On the handlebar stem there will be a serrated marking telling you that the stem should not go any higher; this is for safety reasons; it's very easy to miss the marking if you don't know about it.
At the top is an Allen key bolt that goes along down through the handlebar stem to a wedge at the bottom.
This is to enable you to slide it down into the headset of the bike; when you have done this, position them in straight and tighten the bolt until the handlebars stem is tight.
You can check that it is tight by standing in front of the bike and holding the wheel with your legs and at the same time twisting the handlebars with your hands; they should not move.
Tighten the handle bars with the nut at the front ( see photo).
At this point it will be prudent to tighten the Allen key bolts that hold the brake levers and gear changer on ( although these are usually already tight already).
Important- check that the grips cannot slide off; if they do either glue them on or buy better ones ( slippy grips can kill).
Step 6: The Pedals.
The pedals confuse a lot of people; that is because one of them has a left hand thread.
If you look carefully you can see that each pedal is marked L or R.
The left pedal goes onto the crank without a chainring and is threaded on anti-clockwise.
The right pedal goes onto the crank that has a chainring and is threaded on clock-wise.
These are tightened with a 15mm spanner.
Step 7: Wheels and Brakes.
The back wheel will already be fitted; just make sure that the wheel nuts are tight ( 15mm spanner).
The front wheel will need putting into position, nice and straight with the same amount of gap on each side of the fork.
There will be tab washers; the tab goes into a little hole on the fork and then you can tighten the wheel nuts.
The brake pads will usually need to be lined up with the rim.
As you can see in the photos, the front pads were too high and were rubbing against the tyre.
Using a 5mm Allen key, undo the pad bolts so that they are parallel to the rim and that the bottom of the pad is level with the inner circumference of the rim( hard to explain but easy to see in the photos) and tighten.
Try the brake just to make sure that the pad does not hit the tyre.
If the pads on one side rub then turn the adjusting screw in, a quarter turn, on the side that is rubbing, ( see photo.).
If this fails try the advanced tips step.
Step 8: The Gears
The rear de-railer ( the thing that moves the chain onto different sprockets) should be nice and straight when on the smallest sprocket; sometimes these get squashed in the box so that they are pointing at the spokes.
Next, put the bike in its highest gear and turn the pedals; if the chain comes off then look for the the little screws on the de-railer
( see photo).
Turn the screw marked H ( aitch stands for high) in a quarter turn and turn the pedals again; repeat until the chain does not come off.
Now put the bike into the highest gear and turn the pedals; if the chain tries to go beyond the biggest sprocket then look for the little screws on the de-railer
( see photo).
Turn the screw marked L ( el stands for low) in a quarter turn and turn the pedals again; repeat until the chain does not come off.
Next, if the chain makes a ticking noise as you travel from the high gears to the low gears, as if it is struggling to climb onto the next sprocket, then locate the de-railer adjuster ( see photo).
Give it a quarter turn and try the gears again; repeat until the gears work smoothly.
Sometimes the gears are badly made ( especially non Shimano types and will tick whatever you try; there is not much that you can do about that ).
Step 9: The Bottom Bracket.
Hold a crank in each hand and try to detect any lateral movement or clicking in the bottom bracket.
If there is none, then fine, go on to the next step.
If there is movement then undo the big nut ( pictured); turn clockwise to undo.
With a screwdriver and hammer, gently tap the cone anti-clockwise ( to tighten).
When there is no movement but the cranks still turn freely then lock this off with the big lock nut ( anti-clockwise).
Step 10: The Headset.
The headset holds the forks on and determines how stiff the steering is.
Sometimes this is loose; if you hold the front brake on and push the bike backwards and forwards ; if it is loose you will see the headset slightly move and feel it clicking.
A lot of the time they will be too tight, making the riding experience less fun.
The remedy the ailments:
Undo the big locknut and adjust the knurled cone tighter or looser until the steering feels nice but there is no clicky movement ( as previously described above).
Once you are satisfied lock it off with the big locknut.
Step 11: Reflectors and Bell.
The bell usually clamps onto the left side of the bar; use a small headed screwdriver.
The rear reflector usually clamps onto the seatpost; use a small headed screwdriver.
The front reflector will fit onto the fork; use two 10mm spanners.
The front reflector will clamp onto the handlebar; use a small headed screwdriver.
Step 12: Advanced Techniques.
You can skip this step if the thought of using a spoke key is not for you.
Sometimes the bike will not respond the some of these steps; most people don't care if the brakes rub a little or if it's a little stiff to pedal.
One reason is that they think it doesn't matter because it's just a kid's bike but I like to make a child's first riding experience as nice as possible and in that way they may continue to cycle throughout their life.
The bottom bracket usually comes with no grease.
To remedy this fully undo the locknut and cone in a continuation of the process shown in step 9.
Put in some grease and re-assemble.
Sometimes the wheel has a buckle in it and this will rub on the brake.
If the rim rubs in a particular spot then with a spoke key undo the spoke on that side a half turn; the two spokes on the opposite side should be tightened a quarter turn each.
Repeat until the rubbing stops.
Sometimes the adjusters on the brakes just are too badly made to work; in this case if the brake rubs very hard on one side and you just cannot adjust it then locate the spring that lies vertically along the brake arm.
Pull this out and then bend this out ( as shown ) and put it back into the brake arm.
By doing this you are increasing the tension and that will pull the brake arm away from the rim ( so don't over do it, small steps at a time.)
Step 13: Quick Summary.
Make sure that the brake pads are tight and that the pads do not not rub on the tyre.
Make sure that the bolt that holds each brake cable is tight.
Make sure that the seat post and Handlebar stem are not raised higher than the safety marking.
Make sure that the wheel nuts are tight.
Make sure that handlebar bolt and handlebar stem bolt are tight.
Make sure that the saddle bolts are tight.
Make sure that the grips are tight.
And relax . . .
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