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Diamondback El Oso Niño - 20" Fat Tire Kids Mountain Bike

El Oso Niño - 20" Fat Tire Kids Mountain Bike

38% OFF
Regular price $399.00
Regular price $650.00 Sale price $399.00
Sale Sold out


One Size 3'11" to 4'7"


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Shipped Free Direct to Your Door

This bike does not arrive Ready to Ride. Diamondback bikes require final building and tune to get ready to ride. We suggest taking this bike to a local mechanic for final assembly and adjustments.

 Diamondback Assembly Instructions

Shipped Free Direct to Your Home

Our Platinum Pro Assembly fee of only $39 (reg. $75) will be added at checkout. Your Diamondback kids bike will be built, fine-tuned and expertly packaged by our certified team of bike techs. Your new bike comes 90% built, reassembly is quick and easy with our video guides. Your new bike ships within 3-5 business days.

Pick Up at Bicycle Warehouse

$25 Ready to Ride

Bikes comes 100% built and ready to ride. This fee includes professional assembly & setup, one basic Master Service and free warranty processing. Shipped bikes are not charged this fee.


At Bicycle Warehouse your satisfaction is our top priority. We understand the importance of your happiness with every purchase, which is why we proudly offer our 30 Day Love It Guarantee for your unused gear and 14 days on all bikes. Our exchange and returns process is quick and easy.

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El Oso Nino is the world's smallest fat bike, made for kids who want to monster-truck over everything in their path. Four-inch wide tires sit atop 20"-inch wheels, making for a unique style and ride. Low tire pressure allows the bike to grab every bit of traction available, with extra float for soft surfaces and sand. This little bear’s frame and fork are made from high-tensile steel, tough enough for prowling the neighborhood and the woods. It’s got a seven-speed Shimano grip shifter to charge up hills, and powerful disc brakes for control, allowing riders to go wherever the trail or their imagination takes them — maybe even to the moon! This model fits riders 44”-54” tall, aged approximately 4-9 years old.


  • BIKE FRAME: 20" Hi-Ten Steel Junior Fat Bike, for Disc Brake Only
  • BIKE FORK: 20" Hi-Ten Steel Junior Rigid, w/ Disc Tabs
  • BIKE HEADSET: Threadless
  • BIKE CRANKS: 152mm Steel w/ 40T Single Ring
  • BIKE BOTTOM BRACKET: Square Taper - 5pc
  • BIKE REAR DERAILLEUR: Shimano Tourney FT35, 7 Speed
  • BIKE SHIFTER: Shimano Tourney RS35 Grip Shift, 7 Speed
  • BIKE COGSET: Shimano Tourney TZ21 7 Speed Freewheel,14-28T
  • BIKE CHAIN: KMC 7 Speed
  • BIKE FRONT HUB: Steel 32h Disc, 3/8" Nutted, 135mm OLD
  • BIKE REAR HUB: Steel 32h Disc, Freewheel, 3/8" Nutted, 180mm OLD
  • BIKE SPOKES: 14g Steel
  • BIKE RIMS: 32h Jr Fatty Alloy
  • BIKE TIRES: Chaoyang 20x4.0"
  • BIKE BRAKE LEVERS: Alloy Lever
  • BIKE PEDALS: 9/16" Resin
  • BIKE HANDLEBAR: Alloy, 560mm Wide, 22.2mm Bar Bore
  • BIKE GRIPS: DB Kraton
  • BIKE STEM: Promax 90mm
  • BIKE SEAT: Padded Jr. Diamondback
  • BIKE SEATPOST: Steel 27.2mm
  • BIKE EXTRAS: Tool Kit
  • BIKE BRAKES: Apex Mechanical Disc, w/ 160mm Front /160mm Rear Rotor


Rider Height 44"-55"
Bike Stand Over Height 576.0 mm
Bike Seat Tube Length 272.0 mm
Bike Top Tube Length 508.0 mm
Bike Head Tube Length 115.0 mm
Bike Head Angle 71.0 °
Bike Seat Angle 70.0 °
Bike Wheel Base 927.0 mm
Bike Chain Stay Length 380.0 mm
Bike Fork Offset 45.0 mm
Bike Stem Length 90.0 mm
Bike Handlebar Width 560.0 mm
Bike Crank Length 152.0 mm
Bike Seat Post Length 260.0 mm