How to assemble a kids bike out of the box

Step 4 - Fit the saddle to the bike and tighten into place

First, take a quick look at the seatpost to see if there's a thin smear of grease on the section that will go into the frame. If not, you can apply a little bit as it helps to stop the post seizing into place - you'll thank me when down the line you want to change the saddle height.

Make sure the saddle is straight by aligning the nose of it with the top tube of the frame - it helps to stand at the rear of the bike for this.  If it's not straight it can be uncomfortable and even cause chafing.

We recommend you set the saddle as low as it will go, and then raise it once your child is straddling the bike.  Getting on a bike that is too tall can be quite unsettling.

Note for sizing the bike:  When raising the saddle look for the minimum insertion point on the seatpost as this indicates the minimum amount of seatpost that should be inside the frame to avoid damage. To find it, look towards the bottom of the post for a line that goes around it. This line must not be visible - it must be inside the frame of the bike.  If your child is already at this point on their new bike, then you'll either need to get a longer seat post (if the rest of the bike fits) or more likely the bike is too small for them.

With the saddle aligned correctly, you need to tighten it in place.  This will either be using a quick-release mechanism, or you may need your hex key for this. Don't overtighten - you just need to make sure that the saddle is tight enough so that it won't rotate or slip down when your child is riding the bike.

The seat should be set low enough so the rider can rest their feet flat on the ground when they’re seated on the saddle.

This makes getting on and off the bike much easier and also gives them confidence that they can easily reach the ground if they need to. This is a great technique to use if the child is sizing up to a bigger bike to get them used to the new size.