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
Backordered: Expected Ship 4 weeks or less


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

Speed Silver: Backordered: Expected Ship 4 weeks or less
Power Purple: Ships in 7 to 10 Days
Braap Blue: Backordered: Expected Ship 4 weeks or less

Wheel Size
14 inches

Approx. Age Range
3 to 5 years


No Training Wheels
Optimized for 2 wheels

$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.

The 14" Alpha One is the smallest pedal bike in the Prevelo lineup and fits most 3 to 4.5 year olds. It's packed with features to get little riders off to the right start, including:
  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 with small reach brake levers.
  5. Rear coaster brake (removable with optional freewheel kit).
  6. Front hub 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.


What the bicycle media is saying

bicycling logo
One of the Best Kids Bikes of 2018
a ton of smart features
two wheeling tots logo
Exceptional ★★★★★
With high-end components, sophisticated, yet kid-specific design, and durability to last through several kids, you'll be wishing you were small enough to ride the Alpha One.
red kite prayer logo

From the tiny saddle to the custom 85mm-long cranks, everything on the Alpha One has been thought-through with the dedication and passion I normally see reserved for bikes costing thousands more.


Kid Centric Features

Kid Engineered Crank

prevelo rounded axle bolt

Rounded Axle Bolts

bicycle internally routed cable

Internally Routed Cables

Kid Size Hand Brakes



Sealed Bearings

Quick Adjust Seat Height

built kid tough

Built Kid Tough

Confidence Inspiring Geometry


Alpha One Lifestyle



Customer Reviews

4.9 Based on 50 reviews
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Customer Photos
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  • Reviews

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    john h.
    United States

    Perfect fit! Great design! He won’t put it down!

    Our 2.5 year old switched from his strider to this bike in less than a week. I don’t think this would have been possible without such a great design. The geometry is great for building his confidence- he can reach the ground because the seat really drops low. I almost went with the Alpha 2, but I’m glad we got the Alpha 1. He’ll grow out of it faster, but he has a perfect fitting bike now, which is important to learn on and gain confidence. The bike is also really light, and looks great too. I was also really impressed that his little two year old hands can actually reach the kid size brake levers. Customer service was great, and we’ll be coming back for more when he grows!

    john h. verified customer review of Alpha One
    Angus S.
    United States

    Love this bike

    This bike is both beautiful and functional! It looks like a motorcycle! I love that it's different from anything I've ever seen. It's also perfectly engineered for kids. My son has gotten comfortable on it quickly! The service truly is amazing. I love their personal touch and the Prevelo team has treated us like family! I've already purchased my second one. The Alpha Zero for my younger son. He loves it too!

    Juan Garcia
    Baltimore, Maryland

    The Alpha One is "PERFECTION"

    Jacob @ Prevelo Bikes is phenomenal! This attention to detail in the build of this little bicycle is amazing and his customer support was awesome! I got my son his first balance bike at 2 yrs old for Christmas in 2016. By August, he has mastered it and I felt it was time to start looking into his first pedal bike. After weeks of research (that's how I am) I discovered Prevelo and placed my order for my son's first pedal bike (Alpha One) for his 3rd birthday in early November 2017. The build quality was perfect and assembly a breeze. At first, we had our son ride the bike without pedals so he could get used to the size of the bike since it was bigger than his balance bike. By the 4th day of practicing, he pedaled on his own for the first time. The look on his face was PRICELESS. The lower center of gravity and his ability to put his feet flat on the ground from the seated position is confidence-inspiring for my son. Our whole experience with the Alpha One, from the website, the ordering, the shipping time, packaging, assembly, the quality and customer support has been EXCEPTIONAL. If I could I would rate this product 6 Stars. Because my son is 3.5 yrs old now, I will be looking to order an Alpha Two for him soon since I enrolled in the Trade-Up Program that Prevelo Bikes offers. I can't thank Jacob and his team @ Prevelo Bikes enough for creating and delivering the PERFECT bicycle for my son. Thank you again Jacob and you'll be seeing my son and I sometime this year for his Alpha Two and some TACOS.

    Jill J.
    United States

    Alpha One Review

    After researching bikes for my three year old turning four, I read on line reviews and came across Prevelo bikes. I contacted Jacob and he was so friendly and informative! We settled on the alpha one for her size and just left pedals off so she could learn to balance. She loves the bike and is zooming all over coasting with her feet up so we will be putting pedals on shortly. The bike is amazing quality and easy for her to maneuver due to the light weight of the bike. The bike is also very sharp looking, we will definitively be getting my daughters next bike from Prevelo using the trade up program Jacob has!

    Tom V.
    United States

    I'm NOT easily impressed...

    Being a professional metal fabricator and perfectionist, I'm not at all easily impressed when it comes kids bikes. After reading ALL the reviews and doing my due diligence before choosing my 3 year old granddaughters first pedal bike, I decided to give Prevelo a shot. First off, I was blown away by the lightning quick shipping...I ordered her Alpha One on a Tuesday, and had it in my hands the very next day! After unpacking (very nicely packaged) her Alpha One I gave it a thorough inspection and was blown away by the design of the tube sections and the beautiful TIG welds...the kid sized pedal arms and brake levers...heck, there is nothing overlooked on this bike! Kudos to Jacob & family for being on top of their game! I'd gladly recommend Prevelo bikes to anyone in the market for a new kids bike!