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


Prevelo will be closed from May 24 to 31 as we move to our new location

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

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  • Reviews

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    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
    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

    Derek G.

    Zulu Three purchase at Sea Otter

    This weekend, my 7 year old daughter went to Sea Otter Classic and test rode several bikes in her size range. The Prevelo Zulu Three was the winner by far. On the 4th and final day, we chose to purchase a slightly used Zulu Three from the Prevelo booth. We have done several trail rides since purchasing the bike and my daughter could not be happier. TheMountain Bike geometry and great component package makes for a confidence inspiring bike. Excellent bikes and excellent customer service!

    Derek G. verified customer review of Zulu ThreeDerek G. verified customer review of Zulu ThreeDerek G. verified customer review of Zulu Three
    Aaron M.
    United States

    Zulu 3 is Rad

    I bought the Zulu three for my 6 year old. What a great bike?!?! Out of the box and on the trail in 15 minutes. I’ve been recommending this bike to all my friends. The only downside is my 4 year old wants a Zulu theee now (but he’s not big enough yet!)

    Aaron M. verified customer review of Zulu ThreeAaron M. verified customer review of Zulu Three
    David G.
    United States

    Great Bike

    Purchased the bike for my son's 5th birthday. He is tall for his age but the low standover height makes it manageable for him. Shipping was quick, bike packaged well, and not many adjustments at set up. Also, the fact that they ship direct is a plus in and of itself as many manufacturers will only ship to a bike shop. And if you live in Texas the number of LBS's that carry legit kids bikes are very few and far between. Shifting is smooth and after only a couple of rides, my son has started to figure out how to shift. Now that he can climb, it has become is favorite thing to do which makes me proud, a little perturbed and very winded. Ha! The brakes are definitely an improvement from cable v-brakes. There was enough adjustment in the levers to allow for 1-finger braking by small hands and he's taking to the technique after slapping the binders on a couple of times when grabbing a handful of brakes. All around a great bike that we will get a lot of use out of. Our family rides a lot and if you are looking for a quality bike that will allow your child to progress their skills and confidence on the bike when moving up to 20" look no further.