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OFF AIR 4 20in Mountain Bike - Kids'
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Built for smooth trail progression, woom OFF AIR 4 adds suspension and control
What Our Gearhead® Experts Are Saying:
" I watched this bike handle rough trails, small roots, and loose gravel, and the suspension really makes a difference in comfort and control. The front fork smooths out bumps so riders stay more confident, while the hydraulic disc brakes keep speed in check on descents. The SRAM shifting is also easy to manage, helping riders stay focused on the trail instead of the controls"
Who It’s For
Progressing riders ready for suspension and more technical trails
This bike is for riders who are confident pedaling and starting to explore rougher terrain where added comfort and control matter. It suits those developing off-road skills like climbing uneven surfaces, descending with control, and navigating small obstacles. Riders looking to go beyond smooth paths into more dynamic trail riding will benefit most
What It’s For
Trail riding with bumps, roots, and varied terrain
The OFF AIR 4 is built for dirt trails, gravel paths, small rocks, and uneven terrain where suspension improves comfort and traction. It performs best on rolling trails and beginner singletrack in dry to mixed conditions, where riders can take advantage of the added control and smoother ride feel
Why We Like It
Suspension comfort with lightweight trail capability
The 6061 T6 aluminum frame keeps the bike light and responsive, while the air-sprung suspension fork adds real trail comfort and control with adjustable settings and lockout for efficiency. The 9-speed SRAM drivetrain delivers a usable range for climbing and flat terrain, and hydraulic disc brakes provide consistent stopping power in all conditions. Wide 2.25in tires improve grip and confidence, making this a capable and comfortable mountain bike for progressing riders
Heads up - We do our best to keep bike specs and images current, but occasional component changes can happen without warning-and sometimes the photos might not show the exact build you'll receive. If you want to double-check the details, our Gearheads are always here to help.
Details
- Fits riders 6 to 8 years and 46 to 51in tall for proper sizing and control
- Air-sprung suspension fork with 60mm travel smooths bumps for better trail comfort
- 6061 T6 aluminum frame keeps weight low for easier handling and climbing
- SRAM X5 9-speed drivetrain delivers wide gearing for varied terrain
- Hydraulic disc brakes provide strong and consistent stopping power
- Schwalbe Rocket Ron 20 x 2.25in tires improve grip on loose and uneven surfaces
- Tubeless-ready Alexrims wheelset supports lower pressures for added traction
- Flip-flop stem allows quick handlebar height adjustment for better fit
- Item #WOO000M
- Frame Material
- 6061 T6 aluminum
- Suspension
- hardtail
- Fork
- RST air-sprung suspension
- Front Travel
- 60mm
- Headset
- integrated 1 1/8 - 1in
- Shifters
- SRAM X5 trigger
- Rear Derailleur
- SRAM X5
- Crankset
- forged aluminum
- Chainring Sizes
- 28t
- Crank Arm Length
- 110mm
- Cassette Range
- 11 - 32t
- Brakeset
- 100 x 15mm thru
- Brake Type
- hydraulic disc
- Rotors
- 160mm/140mm
- Handlebar
- aluminum
- Handlebar Width
- 570mm
- Grips
- silicone lock-on
- Stem
- forged aluminum
- Stem Length
- 50mm
- Saddle
- ergonomic
- Seatpost
- aluminum
- Wheelset
- Alexrims
- Hubs
- aluminum
- Front Axle
- 15 x 100mm thru
- Rear Axle
- 12 x 135mm thru
- Tires
- Schwalbe Rocket Ron, ADDIX SPEED
- Tire Size
- 20 x 2.25in
- Pedals
- platform
- Claimed Weight
- 20.3lb (9.2kg)
- Activity
- trail
- Manufacturer Warranty
- 2 years
Built For Real Terrain Riding
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Built For Confident Riding
Lightweight Trail Frame
A lightweight aluminum frame keeps handling responsive and durable for confident riding on trails
Disc Brakes
Powerful disc brakes with adjustable levers provide consistent stopping power and control in mud, dirt, and wet conditions
9-Speed Drivetrain
A wide-range 9-speed drivetrain delivers smooth, precise shifting and reliable pedaling across climbs and descents
Grippy Trail Tires
Tubeless-ready tires balance low rolling resistance with strong grip for confident riding on loose and uneven terrain
Trail-Tuned Geometry
A low center of gravity and longer wheelbase improve balance and stability on uneven terrain
Choose Your Ride
OFF Carbon Fork — Smooth Trails
A lightweight carbon fork keeps the bike efficient and responsive while reducing vibration on smoother trails
OFF AIR Suspension Fork — Rough Terrain
An adjustable suspension fork absorbs bumps and improves traction for more control on rough terrain
Find The Right Size
Geometry Chart
Size Chart
Complete Your Setup
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Made To Grow With Every Ride
woom started in a Vienna garage when two bike‑obsessed dads reimagined kids’ bikes from the ground up, engineering superlight, child‑specific designs that turned first wobbles into real, joyful riding. Today their award‑winning lineup evolves with kids, moving from tiny first bikes to more advanced models that keep pace as skills, confidence, and ride ambitions grow.