Top pick

The Guardian Ethos 16 Inch Bike delighted our testers—and their parents—with its comfortable geometry, colorful designs, and unique brake system, in which a single hand lever activates both the rear and front brake pads at once. Guardian’s founders appeared on Shark Tank in 2016 and successfully convinced investors that their innovative braking system would set them apart from other bike manufacturers. (The company’s balance bike is also our top pick in that category.)

It has kid-friendly geometry that works for most 4- to 6-year-olds. The Guardian Ethos 16 Inch Bike hits all the right notes for a first pedal bike. It has a low standover height of 16.75 inches, and the rider sits comfortably with its upright, BMX-style handlebars. Thanks to the narrow Q factor (the distance between the pedals) of 5.5 inches, our little riders had more control, which is especially helpful for kids who are “all knees and elbows.” You can adjust the seat height by 7 inches, the most among our picks: With a minimum seat height of 18.5 inches and a maximum of 25.5 inches, this bike works for a wide range of kids, and it comes with an easily adjustable, quick-release clamp for that purpose. The handlebar stem has a typical adjustment range of 1.5 inches.

Guardian’s handy RideSizer tool can help you make sure that you’re getting the right-size bike for your kid based on both their height and their experience level. For an additional $40, you can purchase training wheels from Guardian, though we recommend using the balance-bike method instead if your kid is game: You can leave the pedals off this 16-inch bike and lower the seat all the way (you have to remove the rear reflector) to create a makeshift balance bike, and then you can add the pedals when your child is ready.

It has a well-constructed, lightweight steel frame. Guardian went with a steel frame for this bike (the company’s balance bike is aluminum), which is unusual for higher-end kids bikes since aluminum is lighter. But steel is more durable. And at 18 pounds, this 16-inch bike is more compact and therefore more maneuverable than our runner-up and our budget pick. (My 6-year-old is 50 pounds, so this bike is 35% of her body weight, within the ideal range.) The bike’s high-quality construction is apparent from the moment of unboxing, with smooth welding and no protruding nuts or bolts. Guardian’s bikes also come with a steering limiter, which is a simple rubber O-ring that hooks onto a bolt on the fork tube; installing this piece prevents your kid from rotating the handlebars 360 degrees. In addition, the bike comes with a kickstand for ease of storage.

Guardian bikes use an innovative—and effective—braking system. Trademarked as the SureStop Brake System, it is essentially Guardian’s raison d’être. One lever, located on the right handlebar, controls both the front and rear brakes: The rear brake activates first, and then the front brake activates via a wire attached to the rear brake pad. This design makes for perfectly distributed braking power and virtually eliminates the risk of over-the-handlebar accidents, which occur when the front brakes lock up due to the rider’s overeager lever squeezing. Though dual hand brakes are the ultimate choice for control on a bike, Guardian’s system offers kids a simplified, yet effective, version.

Assembly is simple and straightforward. A QR code printed on the outside of the box brings up helpful videos detailing each stage of assembly. The front wheel comes attached to the frame, leaving assembly of the handlebars, seatpost, pedals, and O-ring to you. All tools are provided, with the exception of a Phillips-head screwdriver, which you need to attach the front reflector. The bike is packed securely in its box but without an excess of Styrofoam. All told, assembly took me less than 20 minutes. (The Guardian website says that the process takes five minutes, a claim that I find a bit aspirational.) In my experience, the brakes needed no adjustment, nor did the wheels require alignment.

It offers versatile rubber tires and an ideal gain ratio. In our tests, the Guardian Ethos’s semi-knobby tires, which are streamlined like those of the Woom 3, our upgrade pick, and less bulky than those on our runner-up and our budget pick, did well on pavement, dirt, and grass. Thanks to those less bulky tires, the Guardian Ethos (and the Woom 3) has more zip than the REI REV 16 and the Joystar Totem, but their knobbiness still offers traction on textured terrain. Our riders also felt confident tooling around on the half pipe at the local BMX track, saying that the tires felt “grippy” and “strong.” We haven’t done extensive testing on especially rooty or rutty trails, but judging from the testing we have done, we’re satisfied that overall the Guardian Ethos’s tires make for a smooth ride on fairly varied terrain. We found them steady on wet, wintery roads, too. With this bike’s gain ratio (the amount of power generated by a pedal stroke) of 3.55, our riders could climb mild hills easily but also maintain power on flat roads.

Guardian bikes come in six colors that include fun patterns. Our testers were magnetically drawn to the look of the Guardian bikes. For an added price, Guardian offers cute accessories such as bells, colorful handlebar grips, and water bottles with holders.

Guardian’s customer service team is responsive and accommodating. The company offers a lifetime warranty on frame defects and a one-year warranty on component defects.

Flaws but not dealbreakers

It isn’t the lightest bike. If your child is on the smaller side, and you’re committed to honoring that ideal bike-to-kid weight ratio (30% to 40%), the 18-pound Guardian Ethos might be a bit heavy for them. If that’s the case, you’d be better off with the 13-pound Woom 3.

The brakes are untraditional. Though we found the innovative braking system to be a key advantage of this Guardian bike, some parents might prefer that their kids learn how to brake using a traditional setup, with separate front and rear brake levers (one for each hand). Since young riders should favor the rear brake anyway as they learn safe brake modulation (in the US, the rear brake lever is located on the right side, just as Guardian’s single lever is), adding the front brake lever on the left when they’re ready for a bigger bike is an easy transition for the child. Still, some parents may want their rider to use both brakes right off the bat.

The price fluctuates. This bike’s list price is $290, but it is frequently on sale for $250. Shipping is nearly $30 in the continental US, and if you’re determined to use training wheels, they have an added cost of $40.