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GO 4 20in Bike - Kids'
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The woom GO 4 is where kids learn that gears make hills easier and flat ground faster
What Our Gearhead® Experts Are Saying:
"The gear indicator is the detail that makes this work for kids aged 6 to 8. Instead of counting numbers, it shows incline graphics so a child can look down and immediately understand which gear fits the terrain they are on. That's a genuinely smart way to introduce shifting without making it feel complicated."
woom built the GO 4 as the first geared bike in the GO line, and the microSHIFT twist shifter comes paired with a child-friendly gear indicator that uses terrain graphics rather than just numbers. A 6 to 8 year old can glance down and know which gear matches the hill or the flat in front of them without counting or guessing. Seven gears with an 11-28T cassette give enough range for real variation in terrain, and the 110mm child-specific cranks keep the pedaling motion natural for this age group. The quick-release front skewer makes wheel removal fast, and the ABC fit guide on both bars and seatpost keeps sizing dialed as they grow.
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
- Gear indicator uses terrain graphics so kids aged 6 to 8 know which gear to use at a glance
- Seven gears give enough range for flat ground, gradual climbs, and everything between
- microSHIFT twist shifter is intuitive for kids in this age range learning to shift for the first time
- 110mm cranks are sized for the legs of 6 to 8 year olds pedaling through varied terrain
- Quick-release front skewer makes wheel removal fast for parents and kids alike
- ABC fit guide on bars and seatpost keeps sizing correct through the full 6 to 8 range
- Oversized grip ends cushion crashes while confidence at this age is still building
- woom's 10-year frame warranty covers the rides ahead and the next sibling after
- Item #WOO000F
- Frame Material
- aluminum
- Suspension
- hardtail
- Fork
- aluminum unicrown
- Headset
- integrated 1in
- Shifters
- microSHIFT twist
- Rear Derailleur
- microSHIFT M21SS
- Crankset
- aluminum
- Chainring Sizes
- 28t
- Crank Arm Length
- 110mm
- Bottom Bracket
- sealed cartridge
- Cassette Range
- 11-28t
- Brakeset
- Mini V-brakes
- Brake Type
- rim
- Handlebar
- aluminum
- Handlebar Width
- 560mm
- Grips
- ergonomic lock-on
- Stem
- forged aluminum
- Stem Length
- 40mm
- Saddle
- ergonomic
- Seatpost
- aluminum
- Wheelset
- aluminum
- Hubs
- aluminum
- Front Axle
- quick-release
- Rear Axle
- bolt-on
- Tires
- Schwalbe Little Joe
- Tire Size
- 20 x 1.4in
- Pedals
- platform
- Extras
- reflectors
- Claimed Weight
- 17.2lb (7.8kg)
- Activity
- trail, road cycling
- Manufacturer Warranty
- 2 years
The Perfect Bike To Grow With
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Thoughtful Design Details
Lightweight Design
Lightweight construction—around a quarter of a child’s body weight—makes the bike easier to handle, ride, and carry
Child-Specific Geometry
A low-entry frame and kid-specific design support a natural riding position for easier balance, control, and confidence
Protective Grips
Narrow, ergonomic grips sized for small hands improve control while helping reduce impact risk during bumps or falls
Intuitive Shifting
A simple twist shifter and hare-and-tortoise gear indicator help kids understand when to go faster or slower
Adjustable Fit
Seatpost and handlebar markings allow precise adjustments so the bike maintains a proper fit as kids grow
Ergonomic Saddle
An age-specific saddle is shaped to support a child’s anatomy for better comfort, stability, and riding confidence
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.