Proper bicycle fitting for kids
Children are normally very flexible, hence there is plenty of optional configurations that will work well. For example short or long stems will work on most kids. First let's make sure there are no problems with the seating position. The below are dangerous, make sure your kids bikes never allow these improper configurations. Then we will go into proper configurations.
Dangerous seating positions:
1. The knee is completely straight when pedaling ( this could cause meniscus tear )
2. An over exaggerated knee bend ( this is bad for the joints )
3. Leaning too far forward to hold the handlebar ( this will force them to sit on soft tissue instead of their sit bones which will cause pain behind their private parts.
Proper seating positions:
It is easiest to fit a bicycle to a child if it is adjustable. An angle adjustable stem, rise handlebars, and a saddle with super long rails should give parents the adjustability to make a bike fit for many years.
1. Have the child sit on the bike in a relaxed posture. Make certain they are sitting on their sit bones ( back of their rear end ). If they are leaning too far forward you will need to move the handlebars back. This can be done by rotating the rise bars or bringing the angle adjustable stem towards the back of the bike.
2. Make sure their wrists are straight when the engaging the brake levers. If they are not straight please rotate the levers until the child's wrists is straight on a ray from the shoulders.
3. When the crank is at the furthest point from their hip, they should have a slight knee bend. If the saddle is too low it will be hard to pedal, so make it easier for your child by lifting the saddle. Please make sure their knee is never straight ( if it locks out it could cause an injury ).
4. Make sure the ball of their foot is in the middle of the pedal. If not move the saddle forward or backward as necessary to accommodate. Once this is adjusted their power transfer will increase making riding easier and more fun. Additionally the bike will fit better, hence making it more comfortable.