Guardian 24 Inch Bike Review – ETHOS and AIROS

Whether cruising the neighborhood or on a long family ride, Guardian 24 inch bikes are exceptional. With kid-friendly designs in both traditional boy and girl colors, two models at different price points as well as their proprietary SureStop braking system, there is a lot to love about Guardian Bikes.

We put both the Guardian ETHOS 24 and AIROS (previously called “Original”) to test to see how they compared to each other as well as to other brands. In this review, we’ll cover who Guardian bikes are great for and why!

boy riding a red Guardian 24 inch bike

Guardian 24 Inch Bike Overview

RATING: Highly Recommended

MSRP:$429 – $529

BEST FOR: Neighborhood to everyday riders in at least size 8 pants needing a durable and reliable bike.

SEAT HEIGHT: 25″ – 33″

WEIGHT: 23 lb. (Airos), 25.5 lb. (Ethos)


GEARS: 7-speed Mega Range
FRAME: Aluminum Alloy (Airos), Steel (Ethos)
GAIN RATIO: 2.3 – 5.6
BRAKES: Surestop Dual Hand
FRAME: Aluminum Alloy (Airos), Steel (Ethos)


  • Patented SureStop braking system for faster and more controlled braking
  • Low center-of-gravity design for better balance and maneuverability
  • Great quality build for the price
  • Fun, kid-approved designs


Guardian 24 Inch Bike Video Demonstration

Want to see the Guardian Airos and Ethos 24 inch bikes in action? Check out our video review to learn why kids and parents both love Guardian Bikes.

Guardian ETHOS 24 and AIROS 24 Bikes Put to the Test

By the time kids reach the age of 8 or 9, most are either really into biking or have lukewarm feelings about it.  With scooters and hoverboards becoming more and more popular, bikes can often get a second seat by the time your child is ready for a 24 inch kids bike.

Having an 8 and 10-year-old myself, I’ve witnessed the problem firsthand.  My kids do enjoy riding bikes and will gladly go on family bike rides, but long gone are the days of them begging us to go riding.  That was… until we got the Guardian Bikes 24 inch Airos.  Now they fight over whose turn it is to ride it – the “loser” has to ride the $1,200 mountain bike!

SureStop Brakes help Build Confident Riders (8 and 7-year-old Riders Shown)

Guardian 24 inch kids bikes (Original) Airos and Ethos

Guardian ETHOS 24 vs. AIROS (Original) 24

Guardian’s 24 inch bike is available in their premium “AIROS” line and their A budget-friendly “ETHOS” line.  In this review, we will cover both models, but the main feature of any Guardian Bike is their SureStop proprietary braking system, which is featured on both the Airos and Ethos bikes.  To understand the genius of Guardian bikes, you need to first understand why their system works and why kids love it!

Why Guardian Bikes?

In the words of my 10-year-old daughter, “I love the brakes!  It’s so much easier to only worry about one brake lever.” My kids’ expensive mountain bikes have really nice hydraulic disc brakes and really are AMAZING bikes, but unless we’re headed up the mountain, they both prefer the Guardian simply because of how easy it is to brake.  I was surprised that the brakes on a bike could make that much of a difference, so I hopped on the beloved Guardian and tested out the brakes myself.

Easy reach lever on Guardian Bikes. It's only one lever - the right lever.

Within a few minutes, I understood their perspective.  Braking with SureStop brakes provides a similar feeling to braking in a new car with an advanced braking system versus an older car with a standard braking system. 

Not only is it easier to brake faster, you feel MUCH more in control of the car (bike!).  As a result, you’re a more confident driver in a car with advanced brakes and driving is more fun as well.

Guardian Bike’s SureStop Braking Technology

Guardian’s unique braking system allows the rear and then the front brake to be activated sequentially with the pull of ONE brake lever.  Once the lever is pulled, the back brake is activated.  Once the rear brake has engaged, the SureStop system on the rear brake pad then activates the front brake. 

Graphic showing three steps to Guardian's SureStop braking system. Step One: Child activates brake lever, Step Two: Rear Brake Engages, Step Three: Rear brake activates front brake.

This sequential stopping system allows the bike to stop faster and with more control.  It also prevents kids from going over the handlebars by accidentally braking with just the front brake.

How Do Guardian’s SureStop Brakes Work?

Guardian’s system works via a proprietary rear brake pad that responds to the friction created between the brake pad and the tire’s rim when the rear brake engages.  The friction between the rim and the brake pad pushes the pad slightly forward.  When the pad slides forward, it pulls on the attached wire that then triggers the front brake to engage.

Picture with diagram showing how SureStop brakes work. 1. Rear brake pad slides slightly forward due to friction from rim. 2. Wire on brake is pulled which triggers the front brake.

Is the SureStop System for Everyone?

Yes and no.  SureStop does not allow the rider to brake the front and rear brake independently.  The front brake won’t engage until the rear brake does.  As a result, the SureStop system is not ideal for more technical riders, such as mountain bikers or even more advanced road riders, who need the ability to use their brakes independently.  Our testers LOVE riding their Guardian bikes around the neighborhood, but when we go on trails, the use their mountain bikes that allow for independent braking.

Is the SureStop System Safe?

Yes!  With one lever to pull, we have found the SureStop system to be easier for younger kids to navigate than dual-braking systems.  With no fear of braking wrong, there is less hesitation from kids when it comes to braking. Many parents have expressed concerns over having both brakes dependent on one braking system.  If the SureStop system were to fail (which we’ve never had happen), the rear brake would still engage, just not the front brake. Both brakes will not go out at the same time.

Over the past several years we’ve tested and owned almost 10 different Guardian Bikes and have never had the system fail.  During this time, two of these well-loved bikes have had their shifters go out, but we’ve never had an issue with the brakes.

That being said, if the rear brake itself were damaged or bumped out of alignment during a fall and stopped working, then both brakes would not work because the rear brake couldn’t activate the front brake. Caliper brakes, however, don’t just stop working out of the blue.  They can be damaged during a severe fall, but stopping randomly while riding a bike?  We’ve never heard of that happening in our 10 years of bike testing.

Just like with any bike, it’s a wise practice to check your brakes before starting a ride, and especially after any crashes.

Guardian’s ETHOS vs. AIROS (Original) Models

Guardian’s 24″ bike is available in their premium “Airos” line and their new, budget-friendly “Ethos” line.  Both 24″ bikes come as 7-speeds with grip shifters and are equipped with SureStop brakes.  We’ve extensively tested out both lines and love both of them for their respective price points.

In addition to price, there are some significant differences between the Airos and Ethos bikes that may help you determine which bike is a better fit for your child.  All in all, the more lightweight Guardian Airos line is best for riders who plan on riding longer or more challenging rides, those who ride more aggressively, as well as those who simply want the best quality components.

Guardian 24 Inch ETHOS vs. AIROS

Bike24 Ethos24 Airos
Seat Height25″ – 33″25″ – 33″
Weight$52923 lb.
Shifters7-speed/Grip shift7-speed/Grip shift
DecalsTraditional Water Transfer GraphicsUpgraded Heat Bonded Graphics

How much do Guardian Bikes Weigh?

Ideally, a bike should weigh less than 40% of a child’s weight, but that’s often hard to achieve for kids. (For reference, most adults ride bikes that are no more than 20% of their weight!).  The Guardian 24 inch Airos weighs 23 lb. while the Ethos weighs 25.5 lb.  Compared to similarly priced bikes, Guardian Bikes are several pounds lighter.

Higher-end brands are lighter than Guardian, but don’t come with Guardian’s SureStop braking system, and do come with a heftier price tag.  Guardian Bikes also weigh more than higher-end brands due to their double walled, high-spoke-count wheels.  Built to withstand anything kids can throw at them (even stairs!), Guardian’s durable wheels are sure to stay true.

Frame Design and Components

The main difference in price and weight between the Airos and Ethos bikes is the frame design.  The Airos is built with a lightweight aluminum frame, while the Ethos has a steel frame.  To keep the weight down on the Ethos line, the tubing on the frame is narrower.  The designs and coloring of the frames are very similar, but the more advanced graphics bonding system used on the Airos line allows for more intricate designs.

Guardian AIROS (left) and ETHOS (right)

Wider tubing on Guardian Bikes Airos 24 inch vs skinnier tubs on the Ethos line.

Built with more high-end components, the Airos line comes with a threadless headset while the Ethos has a threaded headset.  The differences between the two were very slight, but the threadless headset on the Airos never got out of alignment, while the Ethos occasionally had to be readjusted when the bike took a hard fall.

Guardian Bikes 24 Airos threadless headset vs Guardian 24 Ethos threaded headset


Guardian’s Airos and Ethos line are very similar in geometry.  Both position the riders in a relatively upright position, which is preferable for most kids, as it helps to center their weight over the hips as well as minimize the strain on their neck when looking forward. 

Young boy riding the Guardian Bikes Airos and the Ethos. His body position is the same on both.

We had our 8-year-old tester, in size 8 clothes, test out both the Airos and Ethos line, and his positioning on both bikes was almost identical.


In order to ensure quality and ease of assembly, every Guardian Bike is checked, tuned, and re-packaged by Guardian’s own mechanics in California BEFORE they are shipped out to customers.  Bikes are NEVER shipped straight from the factory to the consumer. All the bikes we’ve received from Guardian were ridiculously easy to assemble, were put together in less than 15 minutes, and required no additional tuning once assembled.

What size Guardian is best for my child?

Confused about which size is best? If your child is already on a 20″ Guardian bike, the Guardian 24″ is generally a best fit for kids outgrowing the Guardian 20 small. The larger Guardian 26″ is very likely a better option for kids outgrowing the Guardian 20 large.

We sure to use Guardian’s avatar-based sizing guide to help you visualize and confidently determine which size bike frame is best for your child.  Their RideSizer technology will allow you to see how your child will grow on the bike and predicts how long before they outgrow the bike.

The recommended bike size is displayed right away, but their estimations are presented via a chart that is emailed to you (via Guardian). Based on our experience, it works great, but if you have a child with a long torso and shorter legs, be sure to check their inseams against the bike’s minimum seat height to ensure a great fit.  It’s a super cool tool – give it a try below right here on our site.

Guardian Bikes Models and Sizes

Size20″ Small20″ Large24″26″
Review20″ Small Review20″ Large ReviewYou’re reading it!26″ Review
Est. Age5+5+7+8+
Seat Height20.8″ – 26.8″22.5″ – 28.5″25″ – 33″27.7″-33.5″
Child’s Height43″ – 51″45″ – 53″49″ – 61″52″ – 62″
GearingSingle Speed6 Speed7 Speed7 Speed

Guardian 24 Inch Bike Bottom Line

Safe, lightweight, and fun to ride, Guardian’s line of bikes truly stands out. Whether cruising the neighborhood or enjoying extended family bike rides, your child will be in good hands with a Guardian.

FTC Disclosure: Affiliate links are included in this review.  No monetary compensation was provided for this review, however, the reviewed product was supplied by the manufacturer or distributor to help facilitate this review. All opinions and images are that of Two Wheeling Tots LLC.  All content and images are copyrighted and should not be used or replicated in any way. View our Terms of Use.

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