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Bike Size Guide

Cycle King – Bike Size Guide

Use our quick reference charts to select the correct size bike, then read the hints & tips below to ensure the fit is spot on.

Children’s Bike Size Guide

Use the chart below for a quick match by wheel size, age, inside leg and height. Always check the fit in-store where possible.

Children’s bikes are sized by wheel diameter, not frame size. Choose a size that allows them to ride confidently now – buying a bike that’s too big can compromise safety and deter them from cycling.

Balance Bikes12"14"16"18"20"24"
🚲 Wheel Size
Balance Bike12"14"16"18"20"24"
⏰ Approx Age
0–42–33–44–55–66–78–9
👣 Approx Inside Leg
24–40cm38–44cm43–48cm49–52cm50–54cm52–62cm61–67cm
👤 Approx Height
85–100cm88–100cm95–110cm105–120cm114–124cm120–130cm127–142cm

Top Tips for Choosing a Kids’ Bike

  • Prioritise control over growing room: they should be able to start, stop and steer easily from day one.
  • Check standover: they must stand over the frame with a clear gap – especially for off-road riding.
  • Saddle & feet: New riders feel happier when both feet are flat on the ground. Raise the saddle as confidence grows.
  • Test the brakes: make sure each lever pulls fully with just one or two fingers.
  • Keep it light: a lighter bike is much easier for small riders to handle, push and pick up.
  • Bring their usual shoes: school shoes or trainers can change how they stand over and reach the pedals.

Tip: Use inside leg as your main guide and age/height as a cross-check. When in doubt, pop into the store and we’ll size them up properly.

Adult & Teen Bike Size Guide

For riders around 10/11 years and over, use the chart below to match height, inside leg and frame size.

Adult bikes (and most junior bikes from around age 10 or 11 upwards) are measured by frame size, usually from the centre of the bottom bracket to the top of the seat tube.

4'8"–5'0"
(142–152cm)		5'0"–5'4"
(152–163cm)		5'4"–5'8"
(163–173cm)		5'8"–6'0"
(173–183cm)		6'0"–6'2"
(183–188cm)
👤 Rider Height
4'8"–5'0"5'0"–5'4"5'4"–5'8"5'8"–6'0"6'0"–6'2"
👣 Approx Inside Leg
60–70cm68–76cm74–81cm79–86cm84–91cm
⛰️ MTB Frame Size
12–14"14–16"16–18"18–20"20–22"
🚲 Hybrid Frame Size
13–15"15–17"17–19"19–21"21–23"
🏁 Road Bike Frame Size
46–48cm48–50cm50–52cm52–56cm56–60cm+

Top Tips for Adults & Teens

  • Consider how you ride: off-road and trail riders typically prefer slightly smaller, more agile frames, while commuters and leisure riders often prefer a touch more reach.
  • Don’t size up “just in case”: a bike that’s too big can feel unwieldy, especially when stopping, starting or riding slowly.
  • Check stand-over and reach: you should clear the top tube when standing and be able to reach the bars with a relaxed bend in your elbows.
  • Test saddle height: with your heel on the pedal at the lowest point, your leg should be almost straight. Then ride with the ball of your foot on the pedal.
  • Handlebar comfort: if you feel too stretched or too upright, a different stem length or bar style may help – ask us in-store.
  • Take a short test ride: a quick loop around the car park is the best way to confirm the size feels right.

Note: Different brands and frame designs can fit slightly differently. When in doubt, pop in and we’ll size you up properly.

Detailed Fitting Advice
Measuring Inside Leg Length

Age and height guides help, but inside leg measurement is the most accurate way to size a bike — especially for children who grow at different rates.

Two Simple Ways to Measure Inside Leg

1. Book Against the Wall (Most Accurate)

  • Have the rider stand in socks with their back against a wall.
  • Place a hardback book between their legs and raise it gently until it sits snugly like a saddle.
  • Mark the top of the book on the wall.
  • Measure from that mark straight down to the floor — this is the inside leg length.

2. Sit & Stand Method (Quick Alternative)

  • Measure the rider’s standing height.
  • Measure their seated height (sitting upright with legs straight).
  • Subtract seated height from standing height — the difference is the inside leg.

Using the Measurement
Match your measurement to the inside leg ranges in our charts, and use height/age as a cross-check for the safest and most accurate fit.

Wheel Size — Why It Matters

For Children — Choosing the Right Size
Children’s bikes are sized by wheel diameter, not frame size. As wheel size increases, the bike becomes taller and longer, changing both reach and standover height.

Typical children’s wheel sizes:
12" · 14" · 16" · 18" · 20" · 24" · 26" · 27.5" · 29" · 700C

Always choose the largest wheel size they can comfortably and safely control.
If they can only tiptoe, struggle to reach the handlebars or find the bike hard to balance or stop, the bike is too big.

For Adults — Choosing the Right Size
Adult bikes (and bikes for older children/teens) are sized by frame size, usually measured from the centre of the bottom bracket to the top of the seat tube. Taller frames offer more leg extension but can become harder to handle if oversized.

Wheel size on adult bikes is fairly standard (26", 27.5", 29" or 700C), so focus on:

  • Rider height
  • Inside leg measurement
  • Intended use (e.g., off-road vs commuting)
  • Reach and comfort when sitting on the bike

A correctly sized adult bike allows the rider to place the balls of their feet on the ground while seated, maintain a comfortable elbow bend, and ride confidently without overreaching.
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