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
Speed Silver
Power Purple
Braap Blue

Speed Silver: ETA Late April 2019
Power Purple: ETA Late April 2019
Braap Blue: ETA Late April 2019

Wheel Size
24 inches

Approx. Age Range
7 to 11 years


Easy Shifting
RAPIDFIRE+ shifter &
Smart Cage Derailleur

Fast and Free Shipping

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.

The 24" Alpha Four offers an 8-speed Shimano drive train. The 11-34T wide range gearing is the real deal and gives growing riders truly usable gear range. 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. Lightweight aluminum alloy fork with chromoly steerer.
  4. Tektro front and rear v-brakes.
  5. Quick release front and rear wheels for toolless wheel removal.
  6. Three piece crank with squared taper bottom 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 ALTUS 8-speed drivetrain. This 8-speed derailleur has a SHIMANO Smart cage. This unique pulley cage permits the use of a shorter pulley cage without comprising gear ratio width. Because kids’ bikes have small wheel diameters, rear derailleurs on kids bikes hang low and close to the ground. The Prevelo Alpha bikes use Smart cage derailleurs to keep things high and away from the ground.
  9. Shimano ACERA RAPIDFIRE Plus Shift Lever. Small hands have a hard time using twist shifters. We use reliable silky smooth thumb shifters. They are easy for small hands to operate, have an indicator display, and operate just like shifters on high performance bikes.
  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.


What the bicycle media is saying

two wheeling tots logo

The perfect mix of road warrior and basic all-terrain cruiser, the Alpha Four is built with kid-specific geometry for a precise, comfortable fit.

The Prevelo Alpha series is an exceptional line of bikes for eager young riders. Lightweight with a low-center-of-gravity, the Alphas are fun and easy to ride.


Kid Centric Features

kids sized bicycle crank

Kid Engineered Crank

prevelo alpha four kids bike gears

8 Speed Shimano Drivetrain with Wide Span Gearing

prevelo internally routed cables

Internally Routed Cables

prevelo kid size brake and shift levers

Kid Size Hand Brakes and Easy to Use Shimano Rapidfire Shifters



Sealed Bearings

Quick Adjust Seat Height

Built Kid Tough

Confidence Inspiring Geometry


Prevelo Alpha Four Lifestyle



Customer Reviews

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Finnegan W.
United States

Best. Bike. Ever.

My son has struggled to feel comfortable on a gear shift bike for the last several years. Taking him on a ride was always a struggle with lots of complaining that his legs were tired. He LOVES this bike. He asks to go for rides now. He asks, “can we keep going?” And the only complaints I get now are that the rides are too short!

United States

Our SECOND Prevelo Bike!

I thought I'd get a Alpha Four bike for myself, so that my 3 Year old (on an Alpha Two) and I could ride together like "twins". The Alpha Four is only a 24-inch and most adult bikes are 28 inch. My wife laughs at me for riding a kids bike, but my son loves it! Both bikes are fantastic build quality. So easy to assemble - within just minutes. Jacob and his team are amazing. Little items that my son breaks, Jacob replaces them at no charge! BUY a Prevelo Bike. Don't even research anywhere else. This is the best family owned bike company around!

Scott B.
United States

Great bike

My daughter loves her new Alpha 4 and her bike geek Dad does too. For not that much more than a "standard" kids bike by the major brands Prevelo gets you a well put together machine that's lightweight and well spec'd. I've built many bikes myself over the years and I've found nothing to nitpick. Hats off to team Prevelo!

Scott B. verified customer review of Alpha Four
Shanti A.

This is the bike for us

Hi all, I have been riding bikes for thirty+ years - across a variety of disciplines as well - road, mountain, triathlon... this, along with various sizes of hand-me downs from her older brother, make for a busy garage. When it came time to upgrade my 7yo daughter’s bike, a quick web search brought me to Prevelo Bicycles. Seeing the Alpha Four in person at the Westlake Village showroom sealed the deal. After quickly setting the seat height on the demo bike, my daughter simply climbed aboard and rode away. There really is something to be said about a longish wheelbase, low bottom bracket, low Q-factor (narrow) and shorter crankarms. Jacob let me ride the bike around the parking lot; these bikes are both lightweight and sturdy! Solid frame design coupled with quality components make for a bike she’ll be able to grow with for several years. Yes, these bikes are somewhat more expensive than those you’d find at a big box or dedicated bike shop, but I see it as an investment in my daughter’s riding. She will ride longer and more frequently if the bike is enjoyable. There were some nice touches available to customize the bike, such as handlebar grips and name stickers (both pink) for the seat stays. A third party water bottle and cage round out her new bike. Two thumbs way up for Prevelo!

John A.

Prevelo Alpha Four

We are so happy with our purchase. We were looking for a bike that was made specifically for children. We researched other companies that claimed to make bicycles engineered specifically for children but ultimately decided to go with Prevelo, and we couldn’t be happier. One of the reasons we chose Prevelo is because of their esthetic appeal. The bike is beautiful. Our son loves it! We purchased directly from the owner who was kind enough to help our son on his first test ride. As a father himself, he apparently created this company with a self interest. And that interest is a shared interest for all parents looking to invest in a beautiful well made bike geared specifically for kids.

John A. verified customer review of Alpha Four