Kids’ bike fit (in cm) — and why adults learning to ride should start low, then raise the seat
At Pedal Set Go, we want everybody to enjoy riding from the very first roll. A well-fitted bike is the difference between “this is scary” and “I’ve got this.” The most reliable path is to size by inseam (leg length) and seat height, not just age or wheel size. That holds for kids starting out — and for adults learning to ride who need stability first, then efficient pedalling as confidence builds. If you’re brand new, our Learn to Ride resources and lessons will set you up well.
Step 1: Measure inseam (quickly and accurately)
Pop on the shoes you’ll ride in. Stand against a wall, place a hard-back book snugly “saddle-style” between the legs (spine horizontal). Mark the top of the spine on the wall and measure to the floor — that number (in centimetres) is your inseam. Repeat once to double-check.
Step 2: Use inseam to shortlist wheel sizes (cm conversions)
Wheel sizes are still labelled in inches, but the inseam and height ranges below are a practical starting point. Treat them as guides — brands and frames differ, and two bikes with the same wheel size can feel very different due to geometry.
12" wheels: inseam 38–46 cm, height 91–99 cm
14" wheels: inseam 38–51 cm, height 94–112 cm
16" wheels: inseam 41–56 cm, height 104–122 cm
20" wheels: inseam 48–64 cm, height 114–137 cm
24" wheels: inseam 58–71 cm, height 124–150 cm
26" wheels: inseam 64 cm+, height 142 cm+
Parent/carer tip: Don’t buy a bike for kids to “grow into.” Oversized bikes are harder to control, lead to more falls, and can dent confidence that carries into adult years. Choose a bike that fits now, then raise the seat as they progress.
Step 3: Set seat height by skill (in cm relative to inseam)
Seat height for kids and adult-first learners is best chosen relative to inseam. Start stable; raise as skills grow.
Balance bike: seat 1–4 cm below inseam (feet flat, slight knee bend to “run” the bike).
First pedal bike (no trainers): seat ≈ equal to inseam (full foot can reach ground while learning smooth starts/stops).
Experienced pedaller: seat 5–10 cm above inseam (toes down at stops; better leg extension).
Tripod stance (best for learners): when stopping or getting ready to start, keep both feet flat on the ground, legs slightly separated, handlebars straight, and a light squeeze on the brakes. It’s a stable “three-point” base — two feet plus the bike.
Handy reference table (offsets in cm)
Riding stageSeat height relative to inseamBalance/gliding (no pedals)Inseam – 1 to – 4 cmFirst pedal starts/stopsInseam ± 0 cmConfident pedallingInseam + 5 to + 10 cm
Safety note: Never raise the seatpost past the minimum insertion mark. If you need more height, the frame is too small or you’ll need a longer post.
Adults learning to ride: control first, then comfort and efficiency
Adult first-timers benefit from stability first. Begin a touch lower so you can confidently put a foot down during start/stop drills, then raise the seat in small steps (5–10 mm at a time) as balance and braking improve.
Quick baseline: the heel check — sit on the saddle, place the heel on the pedal at the bottom (6 o’clock). Adjust so the knee just straightens. When you swap to pedalling on the ball of your foot, you’ll have a slight, safe knee bend.
Comfort/efficiency target (once confident): with the ball of your foot on the pedal at the bottom of the stroke, aim for a slight knee bend ~25–35° — easy on knees and great for longer rides.
Progress your skills: when you’re ready for real-world streets, our Confident City Rider sessions focus on road positioning on bike-friendly streets.
Why seat height matters at any level — from first rides to Olympians
If you’re chasing maximum power and efficiency (think elite performance or long days in the saddle), correct seat height is critical: it reduces knee strain, improves muscle engagement, and helps you pedal smoothly. For new riders the priority flips — set the seat lower for confidence and control, then bring it up gradually toward that efficient height as skills and comfort grow. Same rider, different goals; seat height adapts to the moment.
When we deliberately lower a confident rider’s seat
Our instructors sometimes drop the saddle a little even for confident riders when the context demands more stability than speed:
Stop-start city traffic with frequent lights and give-way lines
Carrying a child seat, panniers, or a heavy front basket
New to clip-in pedals or testing a different bike set-up
Once the route opens up — fewer stops, longer stretches, or a weekend ride — we raise the seat again for comfort and efficiency. For longer, steadier rides, consider our relaxed guided rides to practise smooth pedalling on bike-friendly routes.
Friendly myth-busting
“Your seat is too low — raise it!”
Don’t let well-meaning but non-educator advice pressure you into a change that trades away control. If you’re learning, carrying a load, or stopping often, a slightly lower seat is a perfectly valid, safer choice. We’ll raise it when the context changes.“Bigger bike is better — they’ll grow into it.”
For learners, slightly too small beats too big. You can always remove pedals and lower the seat to practise gliding and balance. Too big means poor control and avoidable spills.
Why wheel size alone doesn’t guarantee fit
Two bikes with the same wheel size can ride very differently. Frame geometry (standover, reach, seat-tube angle), crank length, and even tyre width affect fit and control. That’s why we prioritise inseam + published seat-height ranges for kids’ bikes, and measured seat height/knee angle for adults — they cut through brand differences.
How this aligns with Pedal Set Go’s approach
Our lessons prioritise confidence first — low-risk drills where you learn smooth starts, controlled stops, and predictable line-holding. As skills click, we raise the seat toward an efficient height so pedalling becomes easier and more comfortable for longer rides on bike-friendly streets. Ready to build those skills with a professional? Book a Learn to Ride lesson (great for beginners and returners), try Back On Your Bike for a friendly refresher, or step up with Confident City Rider. Or just get in touch — we’re happy to help you choose the best next step.
Mini FAQ
Is a lower seat OK if I’m confident but riding in city traffic?
Yes. Lowering the seat slightly improves stability for frequent start/stop or when carrying a load. Raise it again for fewer stops and longer rides.
What if somebody tells me my seat is “too low”?
Unless you’re comfortable and the context suits a higher setting, don’t rush it. If you’re learning, carrying a heavy load, or stopping often, a lower seat is appropriate. Raise it gradually as control improves.
For kids, is “room to grow” a good idea?
No. Oversized bikes harm control and confidence. Fit by inseam in centimetres, then raise the seat as they grow.
Is a bike that’s a bit small OK when starting with pedals off?
Yes. When learning balance (no pedals), a bike that’s slightly too small is better than too big. It keeps the rider closer to the ground and makes starts/stops calmer.
Do I need a specific wheel size to “fit right”?
Wheel size is only part of the picture. Geometry varies across bikes, so always check inseam against the brand’s minimum/maximum seat height and adjust the saddle for the rider’s current skill.
