Guardian 20 Inch Bike Review – Ethos and Original

From their unique graphics that kids love to their patented SureStop braking technology, there is a lot to love about Guardian 20 inch bikes. Kids love the look and feel of Guardian bikes, while everyone loves the additional level of safety that SureStop braking brings to the table.

Available in two different sizes, in geared and non-geared models, with traditional boy and girl colors as well as two different price points, there is sure to be a Guardian bike that fits your neighborhood biking needs. Read about the Original and Ethos models in the review below!

boy jumping off a curb riding a guardian bike

Guardian Bikes 20-inch Overview

RATING: Exceptional (Original), Highly Recommended (Ethos)

MSRP:  $309 – $459

BEST FOR: Kids ages 5 to 8 in need of a durable and reliable bike for everyday use. The simplicity of single-speed bikes makes them ideal for the typical child rider who rides mainly around the neighborhood.

SEAT HEIGHT: Large: 22.5″ – 28.5″, Small: 20.8″ – 26.8″

WEIGHT: Varies by model – Between 18.7 lb. and 22.9 lb.

GEARS: Large: 6-speed, Small: Single Speed

BRAKES: Surestop Dual Hand, no coaster


FRAME: Aluminum Alloy (Original), Steel (Ethos)


  • Patented SureStop braking system for faster and more controlled braking
  • Low center-of-gravity design for better balance and maneuverability
  • Single-speed 20″ small size a great size for those in-between 16″ and 20″
  • Great quality build for the price
  • Fun, kid-approved designs


  • Brake lever can be hard to engage for young riders (5 or 6yo) with smaller hands

Guardian 20 Inch Bike Video Review

Want to see Guardian bikes in action? Check out our video review to learn the 3 reasons why kids and parents love Guardian bikes. Detailed video descriptions of Guardian’s SureStop braking technology is also included.

Guardian 20 Inch Bike Review

Over the years, kids’ bikes have made substantial improvements.  From lighter frames to more responsive brakes, kids’ bikes are finally beginning to get the much-needed upgrades they deserve. Guardian Bikes, a newer kid-specific bike company featured on Shark Tank, saw these improvements and then raised the bar up a notch.  Recognizing the need for not only more responsive brakes but for a safer braking system altogether, Guardian developed their patented SureStop braking system that continues to delight and impress parents and kids alike.

Guardian 20 Inch Large Original

Boy riding Guardian Original 20" bike in black, green, and blue

Guardian 20″ bikes are suitable for kids ages 5 to 8, depending on their height. To better meets the needs of younger riders, Guardian makes a 20″ Small which comes in only single-speed, and for slightly older (and taller kids) they make a 20″ Large which is available as a geared or single-speed.  Both sizes of 20″ bikes are available in Guardian’s premium “Original” line as well as a more budget-friendly “Ethos” line. This review will cover all the 20″ bikes that Guardian offers.

Guardian 20 Inch Small Ethos

Boy riding Guardian Ethos 20" Small bike in black and red

Why a Guardian?

Guardian Bikes were designed and built with one goal in mind – make biking safer for kids by revolutionizing how kids stop a bike. While Guardian bikes have many great features such as lightweight frames and child-specific geometry, their proprietary SureStop braking system is their main selling point.  Unique to Guardian, the SureStop system allows riders to stop faster and with more control.

We’ve seen time and again that SureStop allows kids to feel more in control on their Guardian bike, and as a result, their confidence level increases. With less anxiety about stopping the bike, many kids are more willing to ride more adventurously.  Over the years, we’ve witnessed timid and once hesitant riders learn to love biking as a result of the confidence the SureStop braking system provides them.

Girl riding 20" Guardian kid's bike down the sidewalk. (Turquoise)

But not only is Guardian’s SureStop system safe, it makes braking more fun!  Every time we put a new tester on a Guardian, a HUGE smile quickly plasters their face upon experiencing SureStop brakes for the first time!  Not wanting to miss out on the fun, I hopped on a Guardian and tried out the brakes myself, and quickly understood our testers’ 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.  As a result, you’re a more confident driver in a car with advanced brakes, and driving is more fun as well.

How Does the SureStop System Work?

Guardian’s unique braking system allows the rear and then the front brake to be activated sequentially with the pull of ONE brake lever.   The SureStop system uses standard brake calipers, so upon first glance, their braking system looks very similar to most dual-hand brake bikes.  The difference, however, lies in the rear brake’s ability to activate the front brake.

Guardian Bikes SureStop Braking Technology

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.

The secret lies in Guardian’s proprietary rear brake pad that responds to the friction created between the brake pad and the tire’s rim when the rear brake engages.  This 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.

On Guardian kids' bikes, the rear brake pad slides slightly forward due to friction from the rim, and then the wire on brake is pulled which triggers the front brake.

Benefits of a Single Brake Lever

Dual-hand brakes work great for advanced riders and are essential for technical youth riders (such as mountain bikers), but can be confusing for the average child rider.  If they accidentally brake with just the front brake, the front tire can lock up, which causes the rear tire to come off the ground and potentially throw the child off the bike. 

Sadly, we have seen this happen several times.  With ONE brake lever on the Guardian, a child cannot accidentally brake incorrectly.  They simply squeeze one brake lever and the SureStop system takes care of the rest.

Single brake lever on Guardian 20" kid's bike

Is the SureStop System for Everyone?

Almost everyone! The SureStop system is amazing for everyday kid riders but is not recommend for technical riding.  If your child is planning on mainly hitting the mountain bike trails, the Guardian system isn’t ideal because technical trail riders need to brake the front and rear wheels independently.  The SureStop system is designed for the average child rider who mainly rides on paved surfaces or dirt paths.

Is the SureStop System Safe?

Yes!  The SureStop system uses high-quality brake calipers like those found on many other higher-end bikes.  The only difference between the SureStop system and a regular dual-hand brake system is that the brake pad on the rear brake engages the front brake.  If for some reason the SureStop system were to fail (which we have never seen in our years of testing) the rear brake on the bike would still work, just not the front brake.

Guardian’s Original vs. Ethos Line

Guardian offers 5 different models of 20″ bikes.  Which 20″ bike is best for your child depends on their size as well as how they plan on using the bike. All 5 models feature the SureStop braking system but vary in size, gearing options, and quality level.  Guardian’s Original line is Guardian’s premium line and features higher-end components than their budget-friendly Ethos line.

Guardian 20 Inch Small Models

Features20" Small Ethos20" Small Original

Guardian 20 Inch Large Models

Features20" Large Ethos20" Large Original Geared

Available in the same sizes and with the same basic features, the Original and Ethos line of bikes are essentially like different models of the same car.  The Original is the premium line with an upgraded frame, seat and shifter.  The Ethos line features the same SureStop braking system, but with slightly lower-end components.

Premium “Original” Line: Designed for those who simply want the best.  Also ideal for those kids who ride more aggressively or around hills and need to shift their bike versus shifting mostly as a novelty.  With an aluminum vs. steel frame, the Original frames are also more lightweight than the Ethos frames.

Budget “Ethos” Line: Priced at about $100 less than the Original, the Ethos has a slightly heavier steel frame and more basic graphics.

Guardian Bikes 20 inch Ethos vs. Original

Features20" Large Ethos20" Large Original
Bike20" Large Ethos20" Large Original
Seat Height22.5" - 28.5"22.5" - 28.5"
Weight22.9 lb.21.2 lb.
Shifters6-speed/Grip shift6-speed/Grip shift
DecalsTraditional Water Transfer GraphicsUpgraded Heat Bonded Graphics

Single Speed or Geared Bikes

Unless a child really needs gears to travel long distances or over hills, we generally recommend buying a single-speed 20″ bike for kids ages 5 to 8.  In addition to being more complicated to use, geared bikes require somewhat regular maintenance, which can quickly add up in cost.

The main problem with geared bikes is that the derailleur (the component that changes the gears on the rear wheel) on essentially ALL 20″ geared bikes sits very low to the ground (this includes high-end brands as well).  As a result, they get beat up on a regular basis and can stop working.

The back wheel of a 20" single speed Guardian bike with no derailleur, and the back wheel of a 20" geared Guardian bike with a derailleur.

Whether a child drops the bike down on the derailleur side of the bike, or if they simply take a tight turn, the sensitive mechanisms of the derailleur often need tuning or even replacing.  As a result, we recommend a single-speed bike for basic neighborhood riders, the Ethos 6-speed for those who want gears for fun, and the Original 6-speed for those who NEED gears.


In addition to gearing differences, the geometry of the Guardian’s Original and Ethos lines are different on the 20″ Large size only.  The handlebars on the Original 20″ Large are set lower on the bike than the Ethos 20″ Large, which creates a more aggressive geometry (child is positioned more leaned forward on the bike) than on the Ethos 20″ Large.  While the difference is slight, it is enough that we would recommend the Ethos line over the Original line for more timid riders.

Side by side comparison of the Guardian Original 20" and Ethos 20". The Etho's handlebars are higher and less aggressive.


Ideally, a bike should weigh less than 40% of a child’s weight, but that is often hard to achieve for kids. (For reference, most adults ride bikes that are no more than 20% of their weight!). Compared to similarly priced bikes, Guardian Bikes are several pounds lighter, with the Original line weighing less than the Ethos line.

Higher-end brands are lighter than Guardian but don’t come with Guardian’s SureStop braking system.  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.

The frame design of the Original vs. the Ethos also plays a role in weight differences between the two lines.  The Original line is made out of aluminum while the Ethos is steel.  To help keep the weight down on the Ethos, a narrower tubing was used.

Guardian Original aluminum tubing (left) versus Ethos tubing (right)

Geometric designs on Guardian bikes are popular with kids

Quality & Assembly

In addition to Guardian Bikes’ superior braking system, they’re built with quality components that will last for years to come.  Both lines of bikes come with a kickstand, while the Original also comes with an upgraded threadless headset (for increased responsiveness on tricky terrain), Shimano shifters (more details below), and a seat with thicker padding.

Guardian’s Original threadless headset vs. Ethos threaded

Guardian Original's threadless headset vs. Ethos threaded

Guardian’s Original vs. Ethos Seat

Guardian Original's saddle is contoured while the Ethos' is not.

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. Both bikes we received from Guardian were ridiculously easy to assemble, were put together in less than 15 minutes, and required no additional tuning once assembled.

Does My Child Need a Large or Small?

In order to offer the best fit for your child, Guardian’s 20″ bikes come in two sizes – Small and Large. Guardian’s 20″ Large is similar in size to standard 20″ bikes, while the 20″ Small is a much needed in-between size between a standard 16″ and 20″ bike.

The 20″ Small is designed to ease the jump from a 16″ to a 20″ bike which is often challenging for timid or lightweight riders as well as younger riders who are tall for their age. With tires that are 4″ larger than a 16″ bike, a frame that is several inches longer, and with a significant increase in weight, standard 20″ bikes are often too big for some riders who have outgrown their 16″ bikes.

While the tire size of the 20″ Small is the same as the Large, the wheelbase and the minimum seat height are both about 2″ shorter than the Guardian’s 20″ Large frame, thereby creating a smaller, more manageable bike.  As a result, Guardian recommends the 20″ Small for ages 5+ and the 20″ Large for ages 6+.

If you’re feeling overwhelmed about sizing, we can walk you through a few easy steps to find the best size bike for your child in our Kids Bike Sizes Guide.

Guardian Frame Sizes

Features16"20" Small20" Large 24"
Size16"20" Small20" Large24"
Est. Age4+5+6+8+
Child's Height Range40" - 46"43" - 51"45" - 53"49" - 61"
Seat Height18.5" - 23.5"20.8" - 26.8"22.5" - 28.5"25" - 33"
Wheelbase716 - 719 mm846 mm895 - 898 mm964 mm

Guardian’s Virtual Bike Sizer

To get a good look and feel for the various sizes Guardian Bikes offer, they created a unique and clever RideSizer tool.  Upon entering your child’s height and birthday, RideSizer will display an avatar of your child’s size on whichever size bike Guardian recommends for your child.  You can also change the bike to other sizes to see how your child would fit on them.

As an added bonus, if you enter your email into the RideSizer, Guardian will email you a chart of their estimations for how long your child will fit on the bike.

Based on our experience, the RideSizer tool works great, but if your child is right on the edge between two sizes, be sure to compare their inseam to the bike seat height to ensure a perfect fit.

Guardian 20 Inch Bikes Bottom Line

Safe, lightweight, and fun to ride, Guardian’s line of bikes is simply amazing. Whether cruising the neighborhood or enjoying extended family bike rides, your child will be in good hands with a Guardian.  The Original line is ideal for lighter weight kids who would benefit more from a lighter weight bike, as well as for older kids who NEED to be able to shift quickly.  The Ethos line is an amazing choice for the average child rider who sticks mainly to the neighborhood.

12 Best 20 Inch Bikes for Boys and Girls – we’ve tested every bike on our list!

Guardian 16-inch Bike Review – Ethos and Original

Guardian 24-inch Bike Review – Ethos and Original

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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