How to Fit a Child’s Bike

If you’ve ever ridden your bike for any length of time with the saddle at the wrong height or angle, you’ll know it can be at the very least uncomfortable, and cause longer-term issues if not resolved. Kids are resilient but may just end up not riding their bike if it’s uncomfortable without knowing why.

Before you start on your search for a new bike, there are a couple of measurements that are used to classify children’s bike sizes:

• Wheel size is used by manufacturers but this doesn’t necessarily reflect the size of the bike as these can differ across brands.
• The age of your child can be referenced but isn’t a great indicator as the size of children can vary greatly too.
• Using your child’s inside leg in reference to the bike seat height. This is the most accurate way to get the right-sized bike, regardless of the wheel and frame size.

Measure your child’s inside leg

Note: Inside leg may be called inseam on American bikes

1. Wearing shoes, ask your child to stand against a wall with their feet flat on the ground and hip-width apart.
2. Place a hard-back book between their legs, spine facing upwards.
3. Raise the book until the spine hits their crotch, ensuring the book is parallel with the ground.
4. Measure from the ground up to the spine of the book – this is their inside leg measurement.
5. You could also mark where the spine of the book meets the wall, have the child move away and measure this instead. Wriggly and ticklish children might make the initial task difficult!

 Selecting a bike

Some bike retailers may use the inside leg measurement but you may also be looking at other measurements. You can use the chart below to give you a rough guide of which measurements would fit your child:

Age	Inside leg	Wheel size	Frame size
3+	13 – 16” (34 – 31cm)	12”	8 – 9”
4+	16 – 20” (40 – 51cm)	14”	9 – 10” (22.9 – 25.4cm)
5+	17 – 20” (43 – 52cm)	16”	10 – 11” (25.4 – 28cm)
6+	19 – 22” (49 – 55cm)	18 – 20”	10 – 11” (25.4 – 28cm)
7+	20 – 23” (51 – 58cm)	20”	12” (30.5cm)
7+	21 – 24” (53 – 62cm)	20”	13” (33cm)
8+	22 – 26” (56 – 65cm)	24”	12” (30.5cm)
8+	23 – 26” (58 – 67cm)	24”	13” (33cm)
8+	24 – 27” (60 – 69cm)	24”	14” (35.6cm)
9+	24 – 28” (60 – 72cm)	26”	14” (35.6cm)
Young teens	27 – 31” (68 – 80cm)	26”	17” (43.2cm)

You’re now ready to go and purchase your child’s new bike! Or at least, you’re armed with the knowledge to approach the – usually very helpful – shop assistants.