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

Zulu Three: Sold Out
Zulu Three HEIR: Ships in 7 to 10 Days

Wheel Size
20 inches

Approx. Age Range
5½ to 9 years


Trail Optimized

$15 ShippingIn the Continental USA

Shipping Terms

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

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

1% for the Planet
Prevelo donates 1% of sales to planet worthy causes.

Note: Final component spec is slightly different from the image above. See the "Components" section below for a detailed break down of the components included.
The Prevelo Zulu Three packs high performance mountain bike features into a 20-inch wheel size package. 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. Zulu specific slack head tube angle keeps the bike controlled over rough terrain.
  3. Lightweight aluminum frame with custom formed 6061 triple- butted tubing and TRAPT™ downtube profile.
  4. Available with a lightweight 80mm travel airfork with HM Carbon Fiber / AL6061 lowers & AL7050 hard anodized 30mm stanchions and adjustable rebound, lockout and compression and 15mm Thru-Axle
  5. Rear hub with 12mm Thru-Axle
  6. Flat mount rear brake caliper keeps the rear brake caliper tucked away and protected between the rear chain stays.
  7. Tektro front and rear hydraulic disc brakes.
  8. Shimano ZEE 10-speed drivetrain. This 10-speed derailleur has a SHIMANO Shadow RD+ Short cage. Because of the small wheel diameter on 20-in bikes, rear derailleurs on 20-inch bikes hang low and close to the ground. The Prevelo Zulu Three uses a 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. 11-36T wide span gearing gives riders plenty of range to spin up tough hills.
  10. Kid engineered direct mount cranks. All Prevelo cranks are sized specifically for each model bike, down to the millimeter.
  11. 95% assembled. Just install the handlebar, seatpost, frontwheel, and pedals.


Kid Centric Features

prevelo bikes kids mountain bike crank

Kid Engineered Crank

prevelo zulu kids mountain bike disc brake

Tektro Hydraulic Disc Brakes with Flat Mount Rear Caliper

prevelo zulu three kids mountain bike internal cable routing

Internal Cable Routing

Prevelo Confidence Inspiring Geometry
Slack, Long and Low



prevelo kids mountain bike 20 boost rear hub

Rear Hub with 12mm Thru-Axle

prevelo 20 kids mountain bike carbon air fork

Available Carbon Lower Airfork with Adjustable Rebound

zee derailleur

Shimano Zee Drivetrain with 10-speed 11-36T Cassette

kid jumping mountain bike

0% Digital
100% Real


prevelo zulu three 20 kids mountain bike


Customer Reviews

5 Based on 11 reviews
5 ★
4 ★
3 ★
2 ★
1 ★
Customer Photos
Write a Review

Thank you for submitting a review!

Your input is very much appreciated. Share it with your friends so they can enjoy it too!

    Kerstin K.
    United States

    Excellent Bike - worth the investment

    My son loves this bike! At first he wasn't convinced because it was not his favorite color (red), but after riding a few times on the trails he realized how awesome this bike is. His riding has gotten so much better over the last 2 months. He is finally able to shift gears (his old bike had the revo twist shifters and he could not shift those) and climbing hills without moaning! Major win! Yesterday we took it to a new pump track and he was riding for 3.5 hours straight. This high quality bike is an investment in your little rider, but if you are an avid biker and are taking the kid out on the trail it is a bike that can make them a much stronger rider! If you're thinking about it, take into account how much awesome riding time you'll get with your little shredder and those memories created, not how many years they can ride that size. I absolutely would recommend buying this bike to anyone who is trying to get their kid interested in mountain biking.

    Kerstin K. verified customer review of Zulu ThreeKerstin K. verified customer review of Zulu ThreeKerstin K. verified customer review of Zulu Three
    Matt W.
    United States

    Stop thinking about it just do it!

    This bike is great. Only down side is my kids are now fighting over it. Time for the z4 too.

    Sherene K.
    United States

    Prevelo 3 Zulu incredible

    Absolutely incredible! Our 6 yo son and 8 yo daughter love this bike and have been riding the trails with ease. No surprise they fight over it on occasion :). It has an ideal balance of quality and price point while providing confidence for young riders. Thank you for building awesome bikes for children! Joshua and Sherene

    Steve G.
    United States

    Zulu three heir!!

    I bought this bike for my sons 4th bday. I took him out the next day helped him start “since he is a little short “ he loved it!! Rode next to him and helped him shift . Very happy with the bike. Very well balanced like his Alpha two bike . Steve gilmore

    Steve G. verified customer review of Zulu ThreeSteve G. verified customer review of Zulu ThreeSteve G. verified customer review of Zulu Three
    Jeffrey H.
    United States

    Prevelo Shines for Kids Wanting to Mountain Bike

    Prevelo products and attention to detail is really impressive. Sales and support service has been amazing and responsive. Trade-up program makes it a no-brainer. revelo has thought about this product line very thoroughly. The Zulu Three has the right geometry and perfect components. Don’t hesitate… just buy. - Happy Dad