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

Speed Silver: In Stock
Power Purple: In Stock

Wheel Size
16 inches

Approx. Age Range
4 to 6 years


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.

  • The 16" Alpha Two is the perfect bike for 4 to 6 year olds whether they are just learning to ride or are mastering the trails. It features:
    1. Ships with a bonus short seat post for additional height adjustment.  A short seat post and the tool required to change seat post are included!
    2. Prevelo confidence inspiring low and narrow geometry. Prevelo geometry keeps the rider low, balanced and in control
    3. Lightweight 6061 aluminum frame with custom formed tubing.
    4. Lightweight aluminum alloy fork with chromoly steerer.
    5. Tektro front and rear v-brakes with small reach brake levers.
    6. Front and rear hubs with low profile rounded hex bolts and no harsh edged nuts for little legs to knock against.
    7. Three piece crank with squared taper cartridge bearing bottom bracket and ultra narrow Q factor.
    8. Double chain wheel guard.
    9. Custom made cranks. All Prevelo cranks are sized specifically for each model bike, down to the millimeter.
    10. 95% assembled. Just install the handlebar, seatpost and pedals.
  • Specifications

    Weight (including pedals) 14.5 lbs / 6.6 kg
    Minimum Saddle Height 17.7 in / 450 mm*
    Maximum Saddle Height 25.0 in / 635 mm
    Bottom Bracket Height 7.2 in / 182 mm
    Gain Ratio 3.8
    *The Alpha Two includes a bonus short seat post that allows the saddle height to be lowered to 17.7 inches.
    Standard 300mm seat post height range: 21 in (535 mm) to 25 in (640 mm) 
    Short 200mm seat post height range: 17.7 in (450 mm) to 21 in (535 mm)


    A Wheel Size 16"
    B Wheelbase 28.8 in / 730 mm
    C Effective Top Tube Length 15.4 in / 391 mm
    D Head Angle 69°
    E Seat Tube Angle 69°
    F Chain Stay Length 12.1 in / 307 mm
  • Components

    FRAME 6061 heat treated aluminum alloy custom formed tubing
    FORK Aluminum alloy blades with chromoly steerer tube - 35mm rake
    SEAT CLAMP Aluminum alloy with toolless adjustment
    FRONT BRAKE Tektro aluminum V-brake
    REAR BRAKE Tektro aluminum V-brake
    FRONT BRAKE LEVER Tektro aluminum short reach
    REAR BRAKE LEVER Tektro aluminum short reach
    CRANK SET Prevelo anodized alloy 3-piece square taper with 95MM crank length.
    SPROCKET 25T with double chain ring guard
    BB SET Sealed cartridge
    HEAD SET 1 1/8" threadless
    RIM Aluminum with grinded sidewalls
    FRONT HUB Lightweight alloy 1-piece forged CNC with low profile rounded hex bolts
    REAR HUB Lightweight alloy 1-piece forged CNC with low profile rounded hex bolts - 14T cog freewheel
    TIRE & TUBE Kenda Small Block Eight Pro 16 ×1.5
    SADDLE Prevelo small kid saddle
    HANDLEBAR Prevelo Aluminum - 470mm wide x 50mm rise - 22.2mm to 19mm taper
    HANDLEBAR STEM Aluminum 30mm extension
    GRIP Kraton rubber
    PEDAL Composite with 9/16 chromoly axle
  • Kickstand

        • Custom sized for the Prevelo Alpha Two
        • If you order a kickstand with a bike, it will come installed on the bike
        • Lightweight aluminium alloy
        • Non-corrosive, solid non-porous casting
        • Dual spring pressure plate and snap action mechanism with hardened steel pivot pin
        • Non-slip clamping surface
        • Made in USA


    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 the USA.  We will install the grips on your Alpha Two before shipping.

    custom grip colorsprevelo bike custom grip color


    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


Slick, fun, and fast, the Prevelo Alpha Two 16″ kid’s bike will quickly turn any child into a bike enthusiast.

rascal rides logo

You can’t get a nicer 16″ pedal bike

A big thumbs up


Kid Centric Features

Kid Engineered Crank

Rounded Axle Bolts

Internally Routed Cables

Kid Size Hand Brakes



Sealed Bearings

Quick Adjust Seat Height

Built Kid Tough

Confidence Inspiring Geometry




Customer Reviews

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  • Reviews

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Jace S.
United States

Better than expected

I put a lot of time and way over thought this purchase, and was still surprised at how good this bike is. As an engineer, I have an appreciation for build quality and design that I gained from work experiences. This bike does not disappoint, it's clear that the design and engineering was thought out, and manufacturing processes are well controlled. My son jumped on it took off immediately. He was using a $5 Goodwill Huffy before, to get a taste for pedals, and he was clearly more stable, confident and comfortable on this right away. I was surprised at how noticeable it was. The only adjustment I've made is to bring in the brake lever a little to better match my sons grip. Thanks Prevelo!

Jace S. verified customer review of Alpha TwoJace S. verified customer review of Alpha TwoJace S. verified customer review of Alpha Two
United States

Best kids bike on the market

My daughter has been learning on a balance bike and was ready for pedals. I picked her up a Specialized at the local bike shop and immediately realized a major issue. Coming from a balance bike her reaction was to put her feet down which meant she had no brakes. Prevelo has the perfect solution with a freewheel and hand brakes. Also a smaller seat post is included. My little girl is 3 and a half is and ripping around on the Prevelo.

Daniel W.
United States

Wow - Awesome Bikes!

My wife and I live in the San Francisco bay area with our 4 year old triplets. The terrain around her varies from flat coastal riding to moderate rolling hills. After reading tons of information about bikes online, we went with the Alpha 2. Since the bikes arrived, our kids haven't looked back. We went out for a 10 mile ride recently and they didn't flinch. In fact, after dinner they wanted to go riding again. My big likes are the bike's geometry, higher gear ratio (so they can go faster), responsive brakes, and the styling. I would have liked more color selection, but after the first minute they didn't seem to care. Having different color handlebars did the trick. Looking forward to being a part of the Prevelo family moving forward.

Daniel W. verified customer review of Alpha Two
United States

Amazing, amazing bike and experience

My son received his Alpha 2 as a 4th birthday gift and LOVES it. It took him 1 second to master the peddling and 2 minutes to master the handbrakes. My husband, father in law and I could not believe the ease with which he transitioned from his balance bike to the Alpha 2. The team was so helpful and guided me through the whole process of ordering it over the phone. We live in NYC and received it within 2 days. Great product, beautiful design and the nicest people to work with. Highly recommend buying it.

United States

Alpha Two for my 4 year old - He loves it!!

At 2.5 we got my son a balance bike, and by 4 he was a REALLY solid rider. We knew it was time for his first pedal bike. I wanted to make sure that we got him something that was well made and purpose built for someone his size so he'd have a smooth transition. Fortunately I found Prevelo! We gave my son his Alpha Two on July 4th and he took off immediately!! For the last 2 weeks he's been crushing it. Below are my favorite things about the bike: - Beautiful frame with quality welds - Quality components (Tekro brakes and Kenda tires) - Mid-range gain ratio; high enough to allow him to pickup the speed he needs on the flats but also low enough that he can pedal up hills - Front and rear hand brakes (no coaster break) My son is 41" tall, has a 16" inseam, and weighs 35.4 lbs. He was at the upper end of the 14" Alpha One and the lower end of the 16" Alpha Two. Based on feedback from Jacob at Prevelo I went with the Alpha Two. That model includes a shorter seat post. We are currently using that and my son can get his feet on the ground with no issue. He should have plenty of room to grow! Jacob (owner) was extremely nice and answered all of my questions via email...even spent some time with me on the phone. If you are looking for a quality bike for your child that will last, AND you want to support a family-owned, US-based business, please consider Prevelo.

Anonymous verified customer review of Alpha Two