woom OFF 4 Kids' Mountain Bike
Happy venturing down a gravel path, up a mountain road or on the MTB trail, the 20 in. woom OFF 4 kids' mountain bike can also hold its own on the pavement and is specifically designed for kids.
Key Details
- This bike is stable, responsive and equipped with high-performance components and tubeless-compatible rims and tires
- Ultralight aluminum frame with butted hydroformed tubes has a long wheelbase, sporty geometry and slack steering angle
- Bend in the top tube makes the bike easy to dismount quickly in any situation
- Superlight carbon fork offers maximum stability with minimal weight; multidirectional carbon fibers ensure plenty of torsional strength when steering and braking
- Precise and easy-to-operate SRAM X5 gear system has 9 gears suitable for a wide range of gradients thanks to 28 teeth in the front and an 11-32 cassette in the back
- Easy-to-use SRAM trigger shifter allows riders to shift smoothly and reliably through the gears using their thumb and index finger
- Hydraulic disc brakes improve control on rough terrain and in wet conditions with their excellent modulation and brake levers designed for kids' hands
- Quick-release seatpost clamp allows the saddle to be easily adjusted while remaining secure
- Contact points on the bike are made specifically for kids
- Custom-sized saddle is designed to accommodate the biomechanics of young riders
- Tapered handlebar ends and custom grips are ergonomically designed for kids' small hands, with off-road riding in mind
- Extra rubber on the palm-facing portion of the grips adds comfort; 100% silicone grips provide maximum hand grip
- Pedals are durable and reflective, and they feature slip-resistant pins for extra traction
- Thanks to its flip-flop design, the stem can be turned over and mounted upside down to adjust the handlebar height, helping assure the perfect hand position and fit
- High-quality Schwalbe mountain bike tires with ADDIX Speed rubber compound offer a combo of low rolling resistance, high grip, good shock absorption and excellent durability
- Rims and Schwalbe tires are compatible to be set up as a tubeless system
- Long wheelbase and low center of gravity aid in balancing
- woom-specific molded chainstay protector
- Thru axle provides maximum torsional strength
- Lightweight, forged-aluminum, 4.3 in. (110 mm), kid-specific cranks with narrow tread (Q-factor)
- NOTE: Specs and images are subject to change based on component availability
Imported.
- 1 year of free adjustments (see more below)
- In-store bike assembly
- Pickup in store or curbside
- Bike experts available at 170+ bike shops
- 20% off shop services
- Free tubes with purchase of flat tire repair (Co-op Cycles brand tubes only; tube must be installed at time of purchase)
New bikes go through a normal break-in period, after which they should be readjusted. All bicycles sold at REI include free adjustments for one year after purchase date—as many times as you need. Included: derailleur and brake adjustments, lateral wheel truing, hub and headset bearing adjustments, tire inflation and chain lubrication. Not included: replacement or installation of new components or accessories, any other services. Call your local REI Co-op Bike Shop for more information.
| Best Use | Mountain Biking |
|---|---|
| Frame | 6061 T6 aluminum with butted and hydroformed tubes |
| Mountain Bike Style | Cross-country |
| Bike Suspension | No Suspension |
| Fork | Light carbon fork; 1 to 1-1/8 in. tapered steerer tube; 100 x 15 mm thru axle; post mount for disc brake |
| Crankset | Lightweight, forged aluminum, 4.3 in. (110 mm), kid-specific cranks with narrow tread (Q-factor); narrow-wide chainring with 28 teeth in the front |
| Bottom Bracket | Thun |
| Shifters | SRAM X5 trigger shifter |
| Rear Derailleur | SRAM X5 rear derailleur |
| Rear Cogs | Sunrace 9-speed 11-32T |
| Number of Gears | 9 gear(s) |
| Brake Type | Hydraulic Disc Brake |
| Brakes | Promax Hydraulic disc brakes |
| Brake Levers | Ergonomic brake levers designed for childrens' hands |
| Rims | Tubeless-compatible Alexrims wheelset |
| Front Hub | Front hub for disc brake, 20h, 14 gauge, 100 x 15 mm, 2x bearings without quick release |
| Rear Hub | Rear hub for disc brake, 20h, 14 gauge, 135 x 12 mm, alloy cassette body, 4x sealed bearings; without quick release |
| Wheel Size | 20 inches |
| Tires | Schwalbe Rocket Ron with ADDIX SPEED rubber compound 20 x 2.25 in. |
| Tire Width | 2.25 inches |
| Handlebar Shape | Riser Bar |
| Handlebar | Aluminum; sandblasted; silver anodized; width: 570 mm rise: 20 mm |
| Stem | Forged aluminum; CNC-machined; rise/drop: +/-15 deg. with flip-flop design to adjust the handlebar height; length: 50 mm |
| Seat Post | Anodized aluminum; 27.2 x 250 mm; insertion marks indicate the minimum insertion depth; quick-release seatpost clamp |
| Saddle | Mountain-bike specific saddle with side protection |
| Pedals | Fiber-reinforced nylon; flat; 2 x 6 pins; chromoly axle |
| Headset | Fully integrated 1 to 1-1/8 in. headset; sealed industrial bearings |
| Chain | KMC X9 NPGY 1/2 in. x 11/128 in. |
| Weight | 18 lbs. 8 oz. |
| Bike Weight | Bike weight is based on median size, as sold, or the average of two median sizes. |
| Gender | Kids' |
| 20 IN | |
|---|---|
| Height Range | 46 - 51 |
| Effective Top Tube | 18.1 |
| Head Tube Angle (degrees) | 68 |
| Seat Tube Angle (degrees) | 70 |
| Wheelbase | 33.5 |
Sizing Notes
All measurements are stated in inches unless otherwise indicated.
How we measure bikes
- Standover Height Standover Height is a measurement from the ground to the top of the top tube, measured at the midpoint of the top tube.
- Reach Reach is the horizontal distance from the center of the cranks to the center of the head tube, measured at head tube level.
- Stack Stack is the vertical distance from the center of the cranks to the center of the head tube, measured to the top of the head tube.
- Effective Top Tube Effective top tube is the distance from the center of the head tube to the center of the seat tube/seat post, measured parallel to the ground.
- Seat Tube Center to Top Seat Tube length is the measurement of the seat tube, from the center of the cranks to the top of the seat tube.
- Head Tube Length Head Tube Length is measured from the bottom to the top of the head tube.
- Head Tube Angle Head Tube Angle is the acute angle between the head tube and the ground (measured towards the rear of the bike)
- Seat Tube Angle Seat Tube Angle is the acute angle between the seat tube and the ground (measured towards the rear of the bike).
- Bottom Bracket Height Bottom Bracket Height is a measurement taken vertically from the ground up to the center of the cranks.
- Wheelbase Wheelbase is the measurement from the center of the front axle to the center of the rear axle.
- Chainstay Length Chainstay Length is the measurement from the center of the cranks to the center of the rear axle.
- Fork Offset Fork Offset, or rake, is the distance from the front axle to a line drawn parallel to the center of the head tube or steering axis.
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Customer Images
Build quality excellent, lightweight fun first MTB
The woom air is a fantastic first entry into mountain bike for a younger kid. This model doesn’t have suspension, so if your kid is already hucking off jumps you would probably want that model. But the amazing thing is you can always upgrade the fork! The build quality is fantastic. We had woom 1&2s and the thing we loved still holds true with this modem, it’s super lightweight which is key for a kid who is starting out with a bit of “hike a bike”. The kid wanted me to mention that the seat is comfy, and the shifting is easy, and he loves how lightweight it is. If you have a smaller child, this might not fit until they are 6+. Our son is 44” and he is on top toes as the lowest seat post, so any shorter and you’ll want to wait or look at the woom 3. Love the bike and happy it provides the ability to introduce my fomo son to MTB!!!
Amazing bike
My son LOVES this bike. He started with riding with a guardian when he was 4, and he outgrew it very quickly. He could only go about 3-4 miles on it because of the weight and the fact that it was a single gear bike. With the Woom 4, he is able to ride 6-7 miles at least, and has a blast. The bike is extremely light weight, and having front and rear brakes, and a cassette in the rear makes a huge difference. This bike is definitely a step up. The bike is extremely well made - it looks and feels like a premium bike. It is geared towards mountain biking but it does not have a suspension. The bike came mostly assembled in the box, and the instructions to finish setting it up were extremely easy to follow. The tools needed to put it together are included with the bike. My only disappointment is that it is still too small to fit in my bike carrier. I have a Thule Apex XT 4-Bike Hitch Rack, and the bike does not fit on it.
Good bike, but …
… not for the price. For starters I needed to buy a kickstand separately. The purists will say “but it’s a mountain bike” … yeah, but it’s a kids bike! And for the price, provide the kickstand and let me decide whether to keep it on or not. Additionally, and this will vary from kid to kid … the shifters take a little getting used to, so it’s not really kid friendly from the start. And the gear ratios should include one higher gear. Otherwise solid color and good build.
Awesome kids mountain bike!
This is an awesome kids bike , my 7 year old grand daughter loves it. I had the REI bike shop convert it to tubeless before it left the store. And the 18 lb. range makes it one of the lightest on the market, do a comparison and you see.