Bike for a 4 year old: which Biky fits
By the Biky Bikes team. Updated October 28, 2026.
The Biky Air 14 is the bike for a 4 year old moving from a balance bike to pedals: 11.6 lb (5.2 kg) without pedals, 12.0 lb (5.4 kg) with pedals, $399 (was $449), for riders 37 to 44 inches tall with a 15.5 to 19 inch inseam. The seat starts at 15.5 inches, so both feet reach the ground at a stop, and a light frame is easy for a child to push and lift. The two Tektro hand brakes need 1.1 kgf (10.8 N) at the lever to engage, and the short-reach levers are sized for small hands.
If your 4 year old is 40 inches or taller and already rides, take the Biky Air 16: 12.3 lb (5.5 kg) without pedals, 12.7 lb (5.7 kg) with pedals, $399 (was $489), for riders 40 to 46 inches tall with a 16 to 20 inch inseam. The Air 14 is made for 3, 4 and 5 year olds and the Air 16 for 4, 5 and 6 year olds, so between 40 and 44 inches a child fits both. Measure height and inseam, then check the fit with the Biky Finder.
Biky Air 14 and Air 16 for a 4 year old: specifications
| Model | Biky Air 14 | Biky Air 16 | Biky Air 12 (balance bike) |
|---|---|---|---|
| Who it suits | First pedal bike, after a balance bike | Already rides, needs room to grow | Still learning to balance |
| Wheel size | 14 in | 16 in | 12 in |
| Age | 3 to 5 | 4 to 6 | 1.5 to 4 |
| Rider height | 37 to 44 in | 40 to 46 in | 31 to 41 in |
| Rider inseam | 15.5 to 19 in | 16 to 20 in | 13.5 to 17 in |
| Seat height | 15.5 to 19 in | 18 to 23 in | 12.5 to 16 in |
| Weight without pedals | 11.6 lb (5.2 kg) | 12.3 lb (5.5 kg) | 7.2 lb (3.2 kg) |
| Weight with pedals | 12.0 lb (5.4 kg) | 12.7 lb (5.7 kg) | no pedals |
| Brakes | 2 hand brakes, no coaster | 2 hand brakes, no coaster | Rear hand brake |
| Gears | 1 speed, freewheel | 1 speed, freewheel | none |
| Chainguard | Full, Hebie Chainglider | Full, Hebie Chainglider | no chain |
| Max rider weight | 130 lb (59 kg) | 130 lb (59 kg) | 110 lb (50 kg) |
| Price | $399 (was $449) | $399 (was $489) | $229 (was $259) |
| Limited Edition | $449 (was $499) | $449 (was $539) | $249 (was $299) |
Weights measured by Biky on a hanging scale, tires inflated, no kickstand, September 30, 2026. The pedals weigh 0.4 lb. Frame and fork carry a lifetime warranty for the original owner, returns within 90 days of delivery with a prepaid label. Prices in US dollars, October 28, 2026; the price in brackets is our regular price before October 15, 2026.
Every pedal Biky has two Tektro hand brakes, front and rear, on short-reach levers sized for small hands, and no coaster brake. A lever needs 1.1 kgf (10.8 N) to engage the pads and 1.2 kgf (11.8 N) at full squeeze, measured by Biky with a hanging scale at the lever tip, October 2026, one bike each. That is about 60 percent less force than the other kids bike lever in the same test, so a child stops with a light squeeze instead of a stomp backwards on the pedals.
What the tests say
Two Wheeling Tots, The Best 12 and 14 Inch Bikes for 3 Year Olds, March 2026: Biky Air 14, Best Overall, 97.5 out of 100, "the lightest in our comparison". twowheelingtots.com
Good Housekeeping, 2026 Parenting Awards: Biky Air 14, Learn-to-Pedal Master. goodhousekeeping.com
Two Wheeling Tots, The Best 16 Inch Bikes for 4 and 5 Year Olds, updated October 14, 2026: Biky Air 16, "Most Room for Growth", 93.1 out of 100. twowheelingtots.com
Wirecutter (The New York Times), The Best First Pedal Bikes, 2026: Biky Air 16, "the lightest 16-inch bike we've tested". nytimes.com
Some reviews quote earlier prices. The prices on this page are current as of October 28, 2026.
Common questions
What size bike does a 4 year old need?
A 4 year old fits the 14 inch Biky Air 14 or the 16 inch Biky Air 16, and height decides which. The Biky Air 14 fits riders 37 to 44 inches tall with a 15.5 to 19 inch inseam, and the Biky Air 16 fits riders 40 to 46 inches tall with a 16 to 20 inch inseam. A child between 40 and 44 inches fits both: the 14 inch is easier to start on and the 16 inch gives room to grow.
Should my 4 year old get the Biky Air 14 or the Biky Air 16?
Take the Biky Air 14 for a first pedal bike, and the Biky Air 16 for a 4 year old who already rides and is 40 inches or taller. The Air 14 weighs 11.6 lb (5.2 kg) without pedals and 12.0 lb (5.4 kg) with pedals, the Air 16 weighs 12.3 lb (5.5 kg) without pedals and 12.7 lb (5.7 kg) with pedals. Both cost $399, or $449 for the Limited Edition, and both have two hand brakes and a fully covered chain. The Air 16 seat goes up to 23 inches against 19 on the Air 14, so it lasts through age 6.
How do I measure my 4 year old for the Biky Air 14 or Air 16?
Measure the inseam: the Biky Air 14 fits a 15.5 to 19 inch inseam and the Biky Air 16 a 16 to 20 inch inseam. The child stands against a wall without shoes, you put a book between the legs, and you measure from the floor to the top of the book. Start with the seat low enough that both feet sit flat on the ground; the Air 14 seat starts at 15.5 inches and the Air 16 seat at 18 inches. If the child falls between two models, the smaller wheel is easier to start on and the larger one gives room to grow.
My 4 year old cannot balance yet. Which Biky should we start with?
Start with the Biky Air 12 balance bike, made for 2, 3 and 4 year olds who are 31 to 41 inches tall with a 13.5 to 17 inch inseam. The Biky Air 12 weighs 7.2 lb (3.2 kg), has no pedals and costs $229 with a rear hand brake. The child pushes along with both feet on the ground and learns to balance. Once your child glides with both feet up, or grows past 41 inches, move to the Biky Air 14.
How strong are the brakes on the Biky Air 14 and Air 16, and can a 4 year old squeeze the levers?
The Biky Air 14 and Biky Air 16 levers need 1.1 kgf (10.8 N) to engage the pads and 1.2 kgf (11.8 N) at full squeeze, measured by Biky with a hanging scale at the lever tip, October 2026, one bike each, about 60 percent less force than the other kids bike lever in the same test. Both bikes have two Tektro hand brakes, front and rear, with short-reach alloy levers sized for small hands. There is no coaster brake, so the wheel freewheels and the child stops with the hands.
How fast do the Biky Air 14 and Air 16 ship, and what if the bike does not fit?
Orders ship the same or the next business day and usually arrive in 3 to 5 business days, with complimentary standard ground shipping to the 48 contiguous states. The bike arrives partly assembled, and an adult needs about 5 minutes to finish it. You have 90 days from delivery to return the bike: email info@bikybikes.com first for the return address, and return shipping is on us with a prepaid label. The frame and the fork carry a lifetime warranty for the original owner.
See the Biky Air 14 · See the Biky Air 16 · Find the right Biky by age and height
Bikes for other ages: 2 years, 3 years, 5 years, 6 and 7 years, 8 to 10 years, Gift guide.