How do you set up a child's bike?

Children's bikes are usually designed with easy gearing appropriate to children.
As Chris H said - they are not usually assembled by people who care that a bike is assembled correctly. From the factory it seems like everything is always too tight.

My guess is that there is something that can be adjusted to make things better.
Flip the bike over so it's sitting on it's seat and handlebars.
Pedal the bike and see how it feels. This will give you a baseline to know if you've made improvements as you adjust things.

Things that make a bike hard to pedal:

• You are right to ask about chain tension. If the chain is tight it will be hard to pedal. You may be able to loosen the chain a little and feel an improvement immediately.
• Rear wheel hub adjustment. With the brake disengaged the wheel should spin freely. If it does not you'll need to loosen the bearings on the hub.
• Crank bearings. If the chain tension is OK slip the chain off the chain ring and feel how easy the crank is to move. If the crank is stiff you'll need to loosen the crank bearings.

Edit: Adjusting Chain Tension
(When I started writing this I thought it would be a few steps - but it kept getting longer...)

There is the easier way and the slightly harder way to adjust chain tension.

The Easy Way

1. Remove the nut on the chain side of the wheel that holds the training wheel.
2. With the training wheel off loosen the nut that holds the wheel on.
3. At this point you may be able to squeeze the chain and get a little slack in the chain . Since you are only shifting one side of the wheel adjusting this way can put the wheel off center in the frame. That's OK as long as the tire does not rub on the frame. If you are able to get enough slack in the chain to smooth out pedaling without having a tire rubbing on the frame you are done - go to step 4.
   If the tire is rubbing skip step 4 and to "The Slightly Harder Way" step 1.
   Note: if you wanted to tighten the chain pull the right side (right side of the wheel looking at the wheel from the chain side) of the wheel toward you.
4. Re-assemble in reverse order.

If the tire is too far off center
The Slightly Harder Way (continuing from the previous steps)

1. Get the chain tension where you want it and tighten the nut that holds the wheel. This will set your chain tension.
2. Remove the nut that holds the training wheel on the non-chain side.
3. With the training wheel off loosen the nut that holds the wheel.
4. At this point you may be able to center the wheel and re-tighten the nut. If the wheel won't center - step 5

Picture of the non-chain side and the brake strap after the training wheel is removed. 1. Loosen the screw that holds the brake strap (you may need a wrench to hold the nut on the other side of the screw). 2. Center the wheel
3. Tighten the nut that holds the wheel
4. Tighten the screw that holds the brake strap 5. Put the training wheels back on

Once you’ve bought a kids bike of the correct size, you’ll need to set it up for your child. This is often done in a local bike store (LBS) but if the bike was bought online you’ll need to set it up yourself.

How to set up a child’s bike? There are 3 areas that need to be adjusted;

• saddle / seat
• handlebars
• brakes

This simple article will show you how to do each of these correctly. Depending on the bike, you’ll only need a couple of Allen keys, a Phillips head screw driver (cross), a spanner and about 10-15 minutes.

Table of contents

Why setting up a kids bike correctly is important

There are a few reasons why you’ll want to make sure you’ve set up your child’s bike correctly. The most obvious reason is safety. If your child is riding a bike that’s too big for them then they physically may not be able to operate it.

All of this leads to a lack of confidence, enjoyment and ultimately a child who just doesn’t want to ride. So getting a kids bike to fit is really important for the long-term cycling enjoyment of the child.

Correctly set up a kids bike saddle

There are two parts to setting up the seat on a kids bike; height and angle.

Adjust seat height

To get the height correct you should get the child to sit on the saddle and put their foot flat on the floor. Once they’ve done this raise the saddle about an inch. Now when the child sits on the saddle and touches the floor they’ll be stood with their heel raised.

Doing this will allow the child to easily put their foot down so that they feel safe. They will also be able to go faster with less effort and feel more comfortable while sat on the bike. Specifically, they won’t feel “crunched” up or squashed while riding.

Adjust seat angle

The top of the saddle should be level. You don’t need a spirit level for this — you can just eyeball it. To adjust this you will find either an Allen key (hexagonal hole) or standard nut/bolt on one side of the saddle. Loosen this and then gently ease the front of the saddle either up or down so that it looks level.

Often you’ll see BMX bikes with saddles that point in the air. This is done in conjunction with a very low saddle and is typically done as a fashion statement rather than for function.

Adjust the brakes on a kids bike

This is one of those areas of kids bike set up which gets overlooked. By setting up a child’s bike with brakes that work well and are easy to engage, a child’s confidence grows quickly. They learn to trust themselves and the bike.

“with brakes that work well…kids learn to trust themselves and the bike”

kidsbikeguide.com

Setting up the brakes properly requires attention in two areas;

• the distance of the levers from the handlebars
• the distance of the brake pads from the wheel rims

Adjust brake levers perfectly for a child’s fingers

A child that can comfortably reach and pull on a brake lever is one that will feel more confident riding their bike. Most kids bikes come with brake levers that are not properly adjusted for little hands. Parents don’t know that they can move them closer. Follow these simple steps to do it correctly;

• Loosen the barrel adjuster on the cable where it enters the brake lever.
• Use an Allen key or Philips head screw driver to adjust the ’stopper’ so that the lever is close enough to the bars that the child can grasp it easily.

• With the lever in the correct position, you can now adjust the distance of the pads from the rims by following the steps below.

How to adjust the brakes from the wheel rims

Ideally, we will minimise the distance a child pulls a brake pad through fresh air before it hits the wheel rim. The problem with making this gap too small is that in wet weather any dirt or grime will instantly start to rub/create noise. So a little gap of about 2-3mm on either side of the rim is perfect.

To achieve this there are two places that can be adjusted. Which approach you take depends how big the gap is at the start. If the gap is close to the desired 2-3mm (say 4-5mm) then you can move the pads closer to the rim using a barrel adjuster. This is found near the brake lever, near the calliper or somewhere along the brake cable. This is a small piece of plastic that effectively shortens or lengthens the outer casing of the cable. By lengthening the cable outer the pads will move towards the wheel rim.

Adjust the handlebars

A kids bike with handlebars in the wrong position will cause a few problems. Get it right by following these simple steps and your child will find riding their bike much easier and more rewarding. Start with the handlebars straight up from the stem. If your child is very small for the bike it might be better to adjust the saddle forward on the rails under the saddle rather than tilt the handle bars a long way backwards.

If your child is out-growing the bike then it might be better to fit a stem to move the handlebars away from their body rather than twist them a long way forward.

Ideally, the child is able to sit upright on the saddle with their arms slightly bent. The hand grips should be pretty central over the front wheel. If the grips are too far back the child will have problems steering effectively. If they are too far forward not only will the kid’s ability to steer be compromised but they’ll also risk tipping over the front of the bike (go over the handlebars).

The handlebar height is adjusted by raising/lowering the stem. I’ve often seen kids with their handlebars way too high. This feels uncomfortable — as if the bike is too large and unwieldy. So make sure the handlebars are low down on the headset and that the child isn’t reaching too high up. Their arms should be in a relaxed, slightly downward position.

Other areas to consider when setting up a kids bike

One of the beauties of a child’s bike is that they don’t need too much attention. However, as with anything mechanical a little bit of time spent setting it up properly goes a long way.

Chain adjustment & maintenance

Nearly all kids bikes will have a chain connecting the rear wheel to the pedals. For safety, chains are often enclosed in plastic cases. To see the chain, that plastic cover will need to be removed. Once you can see the chain, you can assess the tension that’s applied.

The chain should be tight enough that it engages properly with the teeth of the gears around the pedal end (chainring) and the wheel hub. However the chain shouldn’t be too tight as that will cause it to wear out too soon. To check how tight it is take hold of the chain at the midpoint between the rear hub and the chainrings and move it up and down. You want to see about 0.7 – 1cm of movement. If there is more than that the chain is too loose, less movement and the chain is too tight.

To solve a loose chain, slacken the nuts on either side of the back wheel. Then gently pull the back wheel backwards so that the chain becomes more taught. This is one of those jobs that’s far better if you have 3 hands so enlist some help if you can. Check that the wheel is square in the bike frame. Look from behind and check the gap between the frame and the tyre is equal on both sides.

If the chain doesn’t go up and down enough when you move it, the chain is too tight. And the back wheel needs moving forward slightly. To do this, just loosen the rear wheel’s nuts a little and the wheel will probably slide forward the right amount. Re-tighten the wheel nuts and re-check the tension. Again, check the wheel is centred in the frame before replacing any chain guard/casing.