Zulu Three

Size Guide

Prevelo Bike Sizing

Getting your kids the right size bike is important and, fortunately, also easy. You just need two pieces of information about your little rider:

  • Inseam
  • Rider Experience

Measuring Inseam

  1. Have the rider stand against a wall, hold a book between their legs so that it is firmly against their crotch (the same place their bicycle seat will be).
  2. Measure the distance from the floor to the top of the book.

Rider Experience

Children who are learning are more sensitive to bicycle height than children who already know how to ride a bike. For this reason, our recommendations for bicycle sizing vary slightly based on the experience lever of the rider. The chart below takes into account the fact that experienced riders tend to adapt better to a bike that is slightly larger. For this purpose we categorize young riders as either "Learners" or "Pedalers"

  • Learner: riders who either have not yet learned to ride a pedal bike, or are still frequently putting their feet on the ground while riding.
  • Pedaler: riders who can ride confidently and only put their feet down to stop.
Model Wheel
Approx. Rider Age
Learner Inseam
Pedaler Inseam
Alpha Zero 12" 1½ + 12.5 to 16.5
Alpha One 14" 3 to 5 13.5 to 16.5 13 to 16.5
Alpha Two 16" 4 to 6 16.5 to 22
15 to 22 
Alpha Three 20" 5 to 9 20 to 23 17.5 to 23
Alpha Four 24" 7 to 11 24.5 to 28 23 to 28
Zulu Three 20" 5½ to 9 22 to 26 20 to 25
Zulu Four 24" 8 to 11 25 to 29 23 to 29


Wheel Size
20 inches

Approx. Age Range
5½ to 9 years


Fast and Free Shipping
Orders in by 12 noon PST M-F ship same day.
(except holidays)

Checked and Tuned
Each bike is checked & tuned prior to shipment.

Easy Assembly
Includes all the tools you need & easy instructions.

  • The Prevelo Zulu Three packs high performance mountain bike features into a package for small riders. Every component is the real deal and is carefully chosen to provide the best performance and fit for young riders ready to tear up the trails. It features:
    1. Prevelo confidence inspiring low and narrow geometry. Prevelo geometry keeps the rider low, balanced and in control.
    2. Lightweight 6061 aluminum frame with custom formed tubing.
    3. Air fork with lockout. This is a real air fork. Lightweight. Adjustable. Effective at soaking up harsh terrain.
    4. Hydraulic disc brakes with special short reach levers for little hands.
    5. Quick release front and rear wheels for toolless wheel removal.
    6. Three piece crank with squared taper cartridge bearing bottom bracket and ultra narrow Q factor.
    7. Custom made cranks. All Prevelo cranks are sized specifically for each model bike, down to the millimeter.
    8. Shimano ZEE 10-speed drivetrain. This 10-speed derailleur has a SHIMANO Shadow RD+ Short cage. Because kids’ bikes have small wheel diameters, rear derailleurs on kids’ bikes hang low and close to the ground. The Prevelo Zulu bikes use high performance short cage derailleurs to keep things high and away from the ground. The derailleur also features a clutch that can be turned on with the flip of a switch to eliminate derailleur bounce over hard terrain and reduce chain drops.
    9. Shimano SLX RAPIDFIRE Plus Shift Lever. Reliable silky smooth shifting and easy for small hands to operate.
    10. Replaceable derailleur hanger. If the derailleur takes a hard hit, the hanger can be replaced without repair to the frame.
    11. 11-34T wide span gearing gives riders plenty of range to spin up tough hills.
    12. 95% assembled. Just install the handlebar, seatpost, front wheel and pedals.
    Weight (including pedals) 23.4 lbs / 10.6 kg
    Minimum Saddle Height 22.8 in / 580 mm
    Maximum Saddle Height 28.0 in / 712 mm
    Bottom Bracket Height 9.8 in / 248 mm
    Gain Ratio 2.0 - 6.2


    A Wheel Size 20"
    B Wheelbase 32.6 in / 827 mm
    C Effective Top Tube Length 17.5 in / 445 mm
    D Head Angle 68°
    E Seat Tube Angle 67.5°
    F Chain Stay Length 13.5 in / 342 mm
  • Components

    FRAME 6061 heat treated aluminum alloy custom formed tubing
    FORK Spinner 300 AIR 20” with adjustable air pressure and lockout
    SEAT CLAMP Aluminum alloy with toolless adjustment
    FRONT BRAKE Promax hydraulic with 160mm rotor
    REAR BRAKE Promax hydraulic with 160mm rotor
    FRONT BRAKE LEVER Promax short reach hydraulic
    REAR BRAKE LEVER Promax short reach hydraulic
    REAR DERAILLEUR Shimano ZEE Shadow RD+ 10-speed with ON/OFF Clutch
    CRANK SET Prevelo anodized alloy 3-piece square taper with 120MM crank length.
    SPROCKET 32T narrow wide with alloy chainring guard
    BB SET Sealed cartridge
    HEAD SET 1 1/8" threadless
    RIM Aluminum doublewall
    FRONT HUB Lightweight alloy 1-piece forged CNC with quick release
    REAR HUB Lightweight alloy 1-piece forged CNC with quick release
    TIRE & TUBE Kenda Small Block Eight Pro 20 × 2.1
    SADDLE Prevelo big kid saddle
    HANDLEBAR Prevelo aluminum big bore - 560mm width x 40mm rise with 31.8mm to 22mm taper
    HANDLEBAR STEM Aluminum 60mm extension
    GRIP Kraton rubber
    PEDAL Alloy pedal with 9/16 chromoly axle and bearings
  • Trying to decide between the Alpha Three and the Zulu Three? Click here to learn the difference:  Alpha Series vs. Zulu Series
  • Kickstand

    • Custom sized for the Prevelo Alpha Three
    • If you order a kickstand with a bike, it will come installed on the bike
    • Lightweight aluminium alloy
    • Non-corrosive, solid non-porous casting
    • Dual spring pressure plate and snap action mechanism with hardened steel pivot pin
    • Non-slip clamping surface
    • Made in USA


    Custom Color Grips

    Customize your new Prevelo with grips in the rider's favorite color. Made for Prevelo out of 100% silicone by ESI in Southern California.  We will install the grips on your Alpha Three before shipping.

    custom grip colorsprevelo custom colored grips


    Rider Name Lettering

    • Custom cut out of 2.5 mil vinyl right here at Prevelo HQ in California and applied to BOTH seatstays before shipment.
    • With a bit of work the decal can be removed when it comes time to hand the bike down.



What the bicycle media is saying

bike radar logo

Prevelo's claims of making a better kids' bike were legit.

two wheeling tots logo

The gateway drug of mountain bikes.

bike dads logo

In the sub $1000 price point, this is the best geared front suspension 20 inch bike we have seen.


Kid Centric Features

Kid Engineered Crank

shimano ZEE derailleur

Shimano ZEE 10-speed drivetrain with Wide Span Gearing

Air Fork with Lockout and Adjustable Compression

kids size bicycle hydraulic brake lever

Small Reach Hydraulic Brake Levers and Shimano SLX RAPIDFIRE+ Shifter



Sealed Bearings

prevelo hydraulic disc brakes

Hydraulic Disc Brakes with 160mm Rotors

Built Kid Tough

1⅛ Inch Headset and 31.8mm bar bore



Customer Reviews

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  • Reviews (2)

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United States

Awesome bike at a good price point

I am very impressed with the quality of the Prevelo Zulu Three and the attention to order detail that Jacob provided. I ordered a short stem at the same time as the bike for my 5y/o son. Jacob saw that and offered to install the short stem and still provided the standard stem in the box so there was one less thing for me to do when the bike arrive and still left me the larger stem for room to grow. The bike shipped extremely fast, the packaging was good, setup required was minimal and my son loves the bike. His riding and confidence have improved substantially in the past few weeks since delivery and the gearing, 20" wheels/tires, have allowed us to ride trails he was not able to ride before. We are both having more fun as a result. There is no other bike on the market at this price point that includes a real air sprung fork & hydraulic brakes. This is a quality bike that will hold its resale value much better than a lesser quality bike when my son outgrows it in a few years. Very happy with my purchase!

Zulu ThreeZulu Three
Mark S.
United States

Fantastic Bike

This is truly a fantastic bike. By using all 'adult' bike parts you end up with a quality bike that can be ridden and maintained. No riveted chainrings and awkward chain guides here. Instead a narrow wide chainring and 10spd, 11-34T cassette will leave your kid climbing like a mountain goat. I was truly shocked by how much terrain my 5 year old could suddenly climb now that he has good gear ratios. Then when we pop out to a road section I just say 'four clicks with your finger' and he's ready to go.

Zulu Three