Frog Bikes Size Guide
Frog Bikes specialises in high-quality children's bicycles engineered for safety, comfort, and growth. Unlike most children's bike manufacturers, Frog sizes bikes by inside leg measurement rather than age alone, recognising that children develop at different rates. This approach ensures each child receives a bike that provides safe ground clearance with the saddle at its lowest setting, while offering long seat posts that accommodate significant growth. Frog bikes are engineered to be lightweight, use child-specific components (such as appropriately-sized brake and gear levers), and feature adjustable handlebars and saddle rails for a customised riding position.
How to Measure Inside Leg Length
Inside leg measurement is the most reliable way to select the correct Frog Bikes size. Follow these steps for an accurate measurement:
- Ask the child to stand in socks against a wall, standing straight and relaxed.
- Place a small book or spirit level between the child's legs, positioning it as high as is comfortable (roughly at the crotch).
- Ensure the book is flush against the wall.
- Mark the top of the book on the wall or ask the child to hold it steady.
- Remove the book and measure vertically from the mark down to the floor using a tape measure.
- Record the measurement in centimetres. For accuracy, measure twice and use the average.
Frog Bikes Size Chart
| Frame Size | Minimum Inside Leg (cm) | Minimum Inside Leg (inches) | Approximate Age Range | Wheel Size |
|---|---|---|---|---|
| Tadpole Mini | 24 | 9.5 | 1–2 | 10" |
| Tadpole | 31 | 12 | 2–3 | 12" |
| Tadpole Plus | 38 | 15 | 3–4 | 14" |
| Frog 40 | 40 | 16 | 3–4 | 14" |
| Frog 44 | 44 | 17 | 4–5 | 16" |
| Frog 48 | 48 | 19 | 4–5 | 16" |
| Frog 52S | 52 | 20 | 5–6 | 20" |
| Frog 52 | 52 | 20 | 5–6 | 20" |
| Frog 55 | 55 | 22 | 6–7 | 20" |
| Frog Road/Track 58 | 58 | 23 | 6–7 | 20" |
| Frog 62 | 62 | 24 | 8–10 | 24" |
| Frog Road/Track 67 | 67 | 26 | 8–12 | 24" |
| Frog 69 | 69 | 27 | 10–12 | 26" |
| Frog Road/Track 70 | 70 | 27 | 11–14 | 26" |
| Frog 73 | 73 | 29 | 12–14 | 26" |
Product-Specific Guidance
Pedal Bikes (Frog Range)
All Frog pedal bikes are sized exclusively by inside leg measurement. The table above lists the minimum inside leg length with the saddle at its lowest position. At this height, the child will safely reach the ground with their feet. Frog bikes feature long seat posts that allow the saddle to be raised substantially as the rider grows, often accommodating several centimetres of growth before a size upgrade is necessary.
Balance Bikes (Tadpole Range)
The Tadpole Mini, Tadpole, and Tadpole Plus are balance bikes designed for younger riders aged 1–4 years. Balance bikes help children develop co-ordination and confidence before transitioning to pedal bikes. The minimum inside leg measurement ensures the child can place their feet firmly on the ground for safety and control.
Road and Track Bikes (Frog Road/Track Range)
Frog Road and Track bikes follow the same sizing methodology as standard pedal bikes but are optimised for on-road and track cycling. These bikes typically feature drop handlebars and lighter frames. Size selection remains based on inside leg measurement; refer to the Frog Road/Track rows in the size chart above.
Frame and Reach Adjustments
All Frog bikes allow handlebar height and fore/aft saddle position adjustment using an Allen key. If a child's proportions differ significantly (e.g., longer arms or torso relative to leg length), these adjustments can improve comfort and control. Instructions are provided in the bike manual.
Sizing Tips
- Always measure inside leg in socks. Children should wear the socks they will wear when cycling to ensure consistency and accuracy.
- Minimum inside leg is the key metric. Frog provides the minimum inside leg length with the saddle at its lowest setting. A child at exactly this measurement will be able to touch the ground safely; children above this measurement will have even more clearance.
- Account for growth. Frog bikes have long seat posts, so many children can grow 5–10 centimetres before requiring a larger frame. However, always prioritise safety and manoeuvrability over the potential to "grow into" an oversized bike.
- Between-size guidance. If a child's inside leg measurement falls between two sizes, choose the smaller size if the child is less confident; choose the larger size if confident and the standover clearance remains sufficient for safety during sudden stops.
- Standover height matters. Ensure there is adequate clearance between the child's inseam and the bike frame when standing over the saddle. This is critical for safety in emergency situations.
- Age is a guide only. The approximate age ranges in the size chart are indicative only. Children develop at different rates, and inside leg measurement is far more reliable than age alone for selecting the correct bike size.
- Test ride if possible. Many Frog Bikes retailers (such as Wheelbase in the UK and other specialist cycle shops) offer in-store viewing and test rides. A test ride is the best way to confirm a bike is safe and comfortable before purchase.
- Lightweight design matters. Frog bikes are engineered to be significantly lighter than many competitors' children's bikes. A lighter bike is easier and more enjoyable for a child to control and ride.