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

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Speed Silver: Sold Out - Next ETA July 2020 - $499
Power Purple: Sold Out - Next ETA July 2020 - $499
Braap Blue: Sold Out - Next ETA July 2020 - $499

Wheel Size
24 inches

Approx. Age Range
7 to 11 years


Easy Shifting
RAPIDFIRE+ shifter &
Smart Cage Derailleur

$15 Shipping
in 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.

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. Lightweight Allen head front and rear wheel skewers for secure wheel installation.
  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
4.9 Based on 91 Reviews
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    Paul T.
    United States United States
    Top Notch

    Bought this as a birthday present for my 8 year old daughter. She is thrilled with her first geared bike, and couldn't be happier. The bike build and components are very high quality and dealing with customer service was a pleasure.

    Heather S.
    United States United States

    At 7.5 yrs old our son decided he was open to learning how to ride a bike. After a lot of research, we wanted to buy a bike that was designed for kids, light weight, and could last for the next few yrs of growth. Couldn't be happier with the purchase, delivery, and design of his bike. Followed the "pedals off first" approach to learning and in one week he's confident and riding along side kids that learned at much younger ages. Thanks so much! Great product. Wish we had done the personalized name inscription.

    Prevelo Bikes Alpha Four Review
    United States United States
    Such great bikes for kids

    I made the decision to get the alpha 3 a few years ago and never regretted it. One son is now older, the younger one inherited the alpha 3, and I had no questions about getting the alpha 4. The build quality is great, with details such as the kid-centric geometry and internal cable routing. The blue color looks fabulous. I made very few adjustments as I assembled the bike. The alpha 3 required some tweaking, but this one was great. My son was very happy on his 8th birthday. Now both boys can chase their mama while she runs. We have recommended prevelo bikes to many of our friends. Thanks for another great bike.

    Prevelo Bikes Alpha Four ReviewPrevelo Bikes Alpha Four Review
    Jon M.
    United States United States
    Best kids bike

    These bikes are so much easier for kids to ride than the standard Walmart or even adult name brand kids versions. My two daughters, 5 & 7 went from riding 12” & 20” bikes to the prevelo 3 & 4 - 20” & 24” bikes within minutes. My 5 yr old had barely learned to ride without training wheels a week prior and was hitting trails within a few days of getting her prevelo. The kid focused geometry, lightweight frame, and hand brakes are so important in giving your kid the ability to ride to their potential. Adding the gears is a huge bonus for taking on hills and speed. So glad we’ve got these bikes, thank you prevelo

    Brock B.
    United States
    Light weight bike is way to go!

    I purchased this bike last spring for my sons 9th birthday. Light weight with a good gear ratio was my goal for a new bike. I had bought him a Trek for his 7th birthday, but he would never rode it because he couldn’t ride up the smallest of hills in our neighborhood. I finally weighed it one day and realized that it weighed more than my XL 29er full suspension mtn bike...How could that be? So that little Trek was 28.5 pounds, my son weighed 75, thats over a third of his body weight. If that ratio were applied to my bike, my bike would weigh in at 58 pounds?In reality, though it weighs more like 25 lbs and i weigh 170.. so no wonder my son hated riding his bike. If my bike were 58 pounds, it wouldn’t be any fun and would wear me out. After researching most of the big name brands such as Trek Specialized and Cannondale, i realized that they all were excessively too heavy. Front shocks, big knobby tires, look really neat, but those extra items all add dead weight that is absolutely unnesassary for a rider in the 70-100 lb range. Fast forward to today, my son now never hesitates to ride his bike. All the neighbor kids have the “other” heavy bikes, but none of them ride them-ever! My son rides the Alpha Four, all the time. He actually asks me now if i want togo bike riding, that never happened before. We even ride to his school which is 2.8 miles away and mostly up hill. He prides him self on being able to effortlessly ride up the steepest of driveways and those little hills in our subdivision? He flys up them like their not even there. This is what you want, a bike that gets ridden.