Zulu Four

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

Same day shipping on orders placed Mon-Fri by Noon PST.
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Wheel Size
24 inches

Approx. Age Range
8 to 11 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 Four 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. If 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) 25.7 lbs / 11.6 kg
    Minimum Saddle Height 26.0 in / 660 mm
    Maximum Saddle Height 32.6 in / 828 mm
    Bottom Bracket Height 10.8 in / 274 mm
    Gain Ratio 2.0 - 6.3


    A Wheel Size 24"
    B Wheelbase 36.9 in / 939 mm
    C Effective Top Tube Length 19.8 in / 503 mm
    D Head Angle 68.5°
    E Seat Tube Angle 71.0°
    F Chain Stay Length 15.4 in / 391 mm
  • Components

    FRAME 6061 heat treated aluminum alloy custom formed tubing
    FORK Spinner SR/Suntour XCR 24" air fork 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 140MM crank length and ultra narrow 131MM Q-factor
    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 24 × 2.1
    SADDLE Prevelo big kid saddle
    HANDLEBAR Prevelo aluminum big bore - 580mm 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 Four and the Zulu Four? Click here to learn the difference:  Alpha Series vs. Zulu Series
  • 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

two wheeling tots logo


Lightweight with trigger shifters, hydraulic disc brakes and a low cage derailleur, the Zulu is a perfectly packaged bike for young mountain bikers ready for adventure


Kid Centric Features

zulu four crank

Kid Engineered Crank

shimano ZEE derailleur

Shimano ZEE 10-speed drivetrain with Wide Span Gearing

kid mountain bike air fork

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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Kelly Jorgensen
American Fork, Utah

Confidence Inspiring!

This is the best kids hard tail mountain bike I've been able to find for under $1000 for my 9 year old son. The geometry on this bike is dialed for young riders! Low stand over and low bottom bracket equals more confidence and ability to control the bike. Correct width handlebars get your kid in a good riding position and improves handling. My son has been having a blast since throwing a leg over this bike. It's light enough for him to climb on real single track trails and built for shredding back down. Hydraulic disc brakes give him plenty of stopping power and keep his little hands from getting sore and tired. Real air fork, grippy tires, crisp shifting and plenty of gears to keep up with mom and dad. I'd recommend this bike to anyone looking to get their kids out on the trails! Thanks for making a proper mountain bike that works for the groms!

April S.
United States

PreVelo Zulu 4 for a 9 year old boy

We bought the PreVelo Zulu 4 for our nephew's 9th birthday. He loves the bike, and it fits him great. A quote for his first ride: "All Right!!" The Zulu 4 is exactly what we wanted: a high quality mountain bike that fits a 9 year old boy. We are very impressed with the obvious quality of the bicycle and definitely feel we got what we paid for, and are extremely glad we bought the bike for him. The only possible negative comment about the bike is that the front brake hose line appears to stick out forward of the bike a bit. Perhaps the hose is a little too long, or perhaps it is just a routing issue with this one bike. Not a problem at all, but is something we noticed. Thank you, The Stone Family