From Wheels to Weight and Height: How to Choose
Wheel size, gears, brakes, oh my! Finding the best kids bike for your child (that also falls into your budget!) is not as simple as it seems. Which bike is best for your child? Is a $300 kid’s bike really that much better than a $60 kid’s bike from Walmart? (Spoiler alert… YES!)
Over the past 10 years, we’ve tested over 100 kids’ bikes. From 12″ bikes with training wheels to high-end 24″ mountain bikes and everything in between, our garages are full and our kids and neighbors are professional bike testers! 🙂
As a result, we certainly know our way around kids’ bikes. In fact, we’ve personally met and consulted with many top kid’s bike brands to help them fine-tune the design of their bikes. We know kids’ bikes better than bike shops (because they specialize in adult bikes) and better than the “bike expert” down the street. Here’s our expert guide to help you find the best bike for your child!
1. What Size Bike Does My Child Need?
Kids' Bikes Sizing Guide
2 - 3
|15" - 18"||3T||36" - 39"|
2 - 4
|15" - 20"||ByK E-250, WOOM 2, Raleigh MXR 12||3T - 4T||37" - 44"|
4 - 6
|16" - 22"||4T - 5||41" - 48"|
4 - 6
|16" - 22"||Priority Start 16, Raleigh Jazzi 16||4T - 5||41" - 48"|
5 - 8
|19" - 25"||6 - 8||45" - 54"|
8 - 11
|23" - 28"||Priority Start 24, REI Co-Op REV||10 - 12||49" - 59"|
|25" +||WOOM 6||12+||56"+|
Wheel size is the most common size indicator for kids’ bikes, and most manufacturers use a child’s age and height to lump them into a wheel size category.
The size of a wheel is determined by its diameter and a bike’s size is determined by this wheel size. A bike with 12″ wheels will be categorized as a 12″ bike and so forth. Standard kid’s bike sizes include 12″, 14″, 16″, 20″ and 24″. The taller the child, the larger the wheel size they will need.
But it’s not that simple!! Due to differences in frame design, the minimum seat height of two bikes with the same wheel size can vary up to 5″! As a result, it’s your child’s inseam (crotch to floor) that is king when it comes to finding the perfect fit! Armed with their inseam, the chart above will help you narrow down which bike size is best for your child.
Once you narrow down the wheel size, compare the bike’s seat height to your child’s inseam. For beginning riders, you ideally want the minimum seat height of the bike to match their inseam. For experienced riders, the minimum seat height should be about 2″ to 3″ more than their inseam.
Want more detailed information on how to fit a bike for your child?
Check out our infographic, Kids Bike Sizes Guide – A NEW Trick to Finding the BEST Fit, to learn our four easy steps to finding the perfect size bike for your child.
2. Seat Height vs. Standover Height
The seat height of a bike is the distance between the ground and the lowest part of the saddle. The seat height is the most accurate indicator of how a bike will fit your child. Due to differences in frame design, bikes with the same size tire can fit a child very differently.
Most bike manufacturers do not state the minimum and maximum seat height of their bikes, so those measurements can be hard to come by. The seat heights of many bikes, however, can be found using our Kids Pedal Bikes: Comparison Charts.
What is the proper seat height for your child? The seat on your child’s bike should be set in relation to their inseam. Our Kids Bike Sizes Guide – A NEW Trick to Finding the BEST Fit demonstrates the best method for measuring a child’s inseam.
First Pedal Bike
A beginning or first-time pedal bike rider should set the seat height to match their inseam. This applies to kids transitioning from a balance bike, tricycle, or bike with training wheels.
With the seat set to their inseam, beginning riders will be able to easily stop as well as regain their balance with their feet. When the child masters starting, stopping, and braking a bike, the seat height can be raised an inch or two.
Second Pedal Bike and Beyond
Having mastered the use of brakes, a child should no longer be depending on his feet to stop. A child should stand on his tippy toes when sitting on the seat in order to allow for proper leg extension when pedaling.
If they can place their entire foot on the ground, a rider can’t get proper extension on the pedal, causing each pedal stroke to be much less efficient. (When a child is riding their first pedal bike with feet flat, they generally ride less efficiently. However, because they’re learning to pedal and balance at the same time, efficiency isn’t your primary goal at that point.)
When purchasing a bike, especially a 20″ or 24″ kids’ bike, it’s also important to take note of a bike’s standover height. The standover height is the height required to stand over the top tube of the bike.
When standing over the bike (not on the seat) there should be an inch or two of clearance between the tube and your child’s crotch.
The gap helps prevent injury if your child slips forward off the seat during a fall. Most top tubes of kids’ bikes are slanted downwards for this reason. For really aggressive riders, it also allows for more clearance when leaning into a turn.
The “standover” height is a common measurement provided by both big and small bike manufacturers.
3. How Much Should My Kid’s Bike Weigh?
Most adults ride bikes that are about 20% of their total weight, while kids’ bikes are usually around 50% of their weight! Ideally, a child’s bike should be less than 40% of their weight. When choosing the right bike for your child, look for the lightest bike you can find in your price range.
Weight, however, should never be looked at in isolation. Some cheap big-box-store bikes are similar in weight to higher-end bikes, but only because their frames are too small and they lack components like hand brakes.
Decreasing the weight on a child’s bike is a priority for well-designed bikes, so higher-end kid’s bike companies proudly display their bikes’ weights. On the other hand, most major bike companies refrain from publishing them.
4. Differences in Frame Design
A child’s body position on the bike plays a large role in how well they can ride the bike. Bikes with a high center-of-gravity and a short wheelbase (distance wheel to wheel) are going to lose their balance and tip over more easily.
When designed correctly, bikes with a longer wheelbase provide more stability and control for the rider.
For beginning riders, bikes with a lower overall center-of-gravity tend to be easier for kids to initiate balance and maintain balance (especially since they often ride at slower speeds). These bikes generally have lower minimum seat heights and longer frames (wheelbases) than other bikes with the same tire size.
The amount of space between the seat and the handlebars is an easy way to estimate a bike’s wheelbase. A bike with a shorter wheelbase will typically have a shorter cockpit and vice versa.
A smaller cockpit provides less room for the rider and can cause kids’ knees to hit the handlebars when turning. The shape of the handlebars can also minimize the cockpit and significantly affect the maneuverability of a bike.
Tall handlebars that sweep back, often found on big-box-store bikes, limit the rider’s space and prevent them from applying more force on the handlebars.
This is especially important for beginning riders. Being able to lean in towards their handlebars helps them get in a better position to begin pedaling as well as to get more leverage on the handlebars.
On the contrary, handlebars that are too low place beginning riders in a really aggressive position, which can cause them to tire out more easily as well as put strain on their neck.
For more adventurous riders, a more aggressive position can be beneficial, but for the average young child rider, a mid-rise handlebar is ideal. For experienced older riders, the shape of the handlebars best for them depends on the type of riding they want to do, but for the average rider, low-rise to mid-rise is best.
5. Hand Brakes vs. Coaster Brakes
The overall quality and performance of brakes on kids’ bikes varies greatly. High-end bikes generally have responsive dual hand brakes that are easy to activate, while lower-end bikes generally only have a coaster brake. Some lower-end bikes do have hand brakes, but they’re often difficult to use.
Coaster brakes (back-pedal brakes) are the standard on most 12″ to 16″ bikes as they are cheaper and essentially maintenance-free, but they can be a headache for kids learning how to pedal.
Kids naturally pedal backward on a bike when they start to lose their balance, or when riding uphill. On a freewheel bike (a bike without a coaster), backpedaling helps kids regain their balance and allows them to keep riding.
On a bike with a coaster brake, backpedaling causes unexpected stops, leading to falls and also delaying a child from mastering pedaling. For experienced riders, coaster brakes can cause them to lose all their momentum when riding uphill.
As a result, we recommend freewheel bikes for beginning and experienced riders, but they can be expensive and hard to come by. In fact, coaster brakes are required by the CPSC on most 12″ and 14″ kids’ bikes as well as some smaller 16″ bikes. Past 16″ bikes, bikes are larger enough to not require coaster brakes.
Around the age of 3.5, kids have enough hand-eye coordination to use a properly designed hand brake. Hand brakes are generally more efficient and much more intuitive than coaster brakes, but they aren’t without their downfalls.
Hand brakes do require maintenance and the vast majority of hand brakes on kids’ bikes, especially those on lower-end bikes, are poorly designed.
Hard to reach and hard to activate, most of these brakes are not designed for kids’ smaller and weaker hands. To test whether a hand brake is easy to use, pull the brake lever with your pinky finger.
If the brake is hard to activate with your pinky, you can try to adjust the brake lever, but more than likely the brake is poorly-designed and will be a challenge for your child to use. Kids should not have to slam on their brakes to stop.
On the contrary, well-designed brakes are very responsive and when activated, easily stop a bike with minimal effort by the child. Designed with small reach levers that are much closer to the handlebar grips than standard levers, well-designed brakes are easier to activate and easier to pull.
In fact, when riding a high-end bike for the first time, we highly recommend having kids walk the bike before riding it to help them get a feel for the proper amount of pressure needed to stop the bike (which is usually much less than they anticipate).
It’s also important to note whether the hand brakes activate the front or rear tire. While unlikely on small 12″ to 16″ bikes, kids on larger 20″ and 24″ bikes can endo (fly over the handlebars) if they brake only on the front tire.
Upon doing so, the front tire of their bike will quickly stop, causing the rear tire to come off the ground, creating the potential to go flying over the handlebars. In the U.S., it’s standard for the right-hand brake to activate the rear tire and the left brake the front.
As a result, it’s vital to teach kids to brake with BOTH their hands or with just their right hand (rear brake).
Types of Hand Brakes
In addition to being easy to reach, it is important to note the type of braking system used as their quality and performance can vary greatly. There are three basic types of braking systems used on kids bikes, single-pivot, v-pull and disc. The type of braking system a bike has is pretty easy to determine just by looking at the bike. Single-pivot and v-pull brakes attach to the frame and “pinch” the rim on the bike, while disc-brake systems are easy to spot via the large disc in the middle of the bike’s tires.
Single-pivot braking systems are found on most budget bikes and are significantly more finicky than v-pull and disc brakes. Even when they are properly aligned to work, they offer less stopping power and typically do hold up with time and use as compared to v-pull. In fact, most bikes with a single-pivot braking system also come with a coaster brake as a backup.
Having had several poor experiences with single-pivot brakes we much prefer bikes with v-pull, BUT the quality of the single-pivot brakes also tend to vary greatly with price. The single-pivot brakes we have tested on a $200+ ByK bike did perform significantly better than those on a $100 Huffy bike.
V-pull brakes are found on essentially all mid and high-range kids bikes. V-pull brakes are also the standard braking systems used on most adults bikes as well (with exception to higher-end specialty bikes).
Durable, easy-to-adjust and rugged enough to maintain alignment over time, V-pull brakes offer significantly more stopping power than single-pivot brakes and are typically always worth the additional cost. With various manufacturers producing v-pull brakes, overall quality and performance can vary, but we still prefer them over single-pivot brakes.
Disc-brakes are not common on kids bikes, but they can be found on higher-end kids bikes, especially mountain bikes. Disc brakes can by hydraulic or mechanical, but for the average everyday rider, the extra-stopping power offered by any disc-brakes are often not worth the additional cost.
Regardless, the braking power on disc brakes is top-notch, so if it’s in your budget, you can’t go wrong with disc brakes.
Specialty Hand Brakes
To prevent potential injuries from braking (going over the handlebars), Guardian Bikes created a unique SureStop system. The system relies on v-pull brakes but allows both front and rear brakes to be activated with one pull on the right brake lever.
Currently only available on 16″, 20″ and 24″ bikes, more information about their unique system can be found in our Guardian 20″ bike review.
WOOM bikes also developed a clever solution for improving safety. Young kids often get confused between their left and right, so WOOM bikes made their right-hand brake lever green to remind kids which brake lever to use.
6. Do I Need to Worry About the Gearing of a Bike ?
Single speed bikes may only be one speed, but you still need to consider what that single speed is! The gain ratio of a bike determines how easy it is to start pedaling a bike as well as how fast you can get going on the bike. All 12″ to 16″ bikes are single-speed, while 20″+ bikes may be single or have gears.
Gain ratio is a number that’s determined by the wheel size, crank arm length (the pedal arm length), and the number of teeth on the front and rear cogs.
A high gain ratio requires more effort to get started but allows the bike to travel further with every pedal stroke (like a high gear on an adult bike).
A low gain ratio requires less effort to get the bike started but requires more “pedal spinning” to get the bike going (like a low gear on an adult bike).
The older and/or stronger a child, the higher the gain ratio they will be comfortable riding.
The differences between the gain ratios of kids’ bikes are slight but do make a difference in the ride-ability of a bike. Lower gain ratios, like a 3.02 on the woom 3, are better for timid kids or those who plan on riding up hills.
Higher gain ratios, like a 4.5 on the Dimensions 16, are best for eager kids who are ready to muscle their way up hills or quickly gain speed on flat surfaces.
Gain Ratios are NOT provided by any bike manufacturer, but we have calculated many for you and have them listed in our individual bike reviews.
Bikes with Gears
Gears are available on some 20″ bikes and most 24″ bikes. Geared bikes typically require much more maintenance than single-speed bikes and can be hard for a child to use. The main concern with geared bikes is the shifting mechanism, known as the derailleur, which is located on the rear axle of the bike.
These derailleurs easily get damaged from the bike being dropped on the ground and are notorious for not working properly. As a result, we recommend only getting a bike with gears if your child truly plans on using them.
20″ and 24″ bikes are typically available with 7 or 8 gears that are shifted with one shifter on the right hand. Unlike most adult bikes that have two shifters (each hand shifting the front or rear derailleur), kids’ bikes typically have fewer gears and only one derailleur on the rear tire. Having only one shifter is much easier for kids as they can simply shift up or down without having to worry about which shifter to use.
Grip Shifter vs. Trigger Shifter
Geared bikes are available with grip or trigger shifters. Grip shifters are activated by twisting the grip forward or back with the palm of your hand, while trigger shifters are activated by pulling or pushing on levers with your fingers.
In general, grip shifters are preferred by more timid or beginning riders as they are often easier and more intuitive to use. Aggressive riders, especially mountain bikers, prefer trigger shifters.
Low-end vs. High-end
The overall quality of the derailleurs in a gearing system can vary greatly from bike to bike. Components on lower-end bikes are notorious for easily getting out of tune.
When a derailleur or shifter isn’t working properly, it’s common for only 1 or 2 of the gears on the bike to actually be useable. Shifting to the other gears will cause the chain to come off. Other times, the chain will try to move, but can’t, which will result in the bike making a loud noise as you pedal.
Higher-end bikes typically have more robust systems that can better handle the wear and tear from kids. Regardless of the amount of money you invest in a bike, teaching kids to always lay a bike down with the gears and chain pointing up (not towards the ground) can go a long way in helping to keep a bike in tune.
For kids who want the fun and flexibility that gears offer, but without the hassle of bulky and finicky derailleurs, bikes with internally-geared hubs are a great option. With an internally-geared hub, instead of a chain moving up and down a cassette, the hub smoothly changes the gears of the bike inside its enclosure on the rear wheel. With no external moving parts, internally geared hubs require very little maintenance and also provide much smoother gear changes.
An additional advantage of an internally-geared hub over a derailleur is that the bike doesn’t have to be moving to shift gears. On a traditionally geared bike, the bike should only be shifted while the bike is in motion, but on a bike with a geared hub, kids can shift while the bike is stationary! Internally-geared hubs can be found on the Priority 20″ and the Cleary 3-speed Owl.
Gain Ratios with Geared Bikes
If your child is riding on a lot of hills, be sure to take note of the gain ratios of the various speeds on the bike. A bike with the lowest gear having a gain ratio of 3 is going to be much harder to ride up steep hills than on a bike with the lowest gear closer to 2. If you’re interested in the gain ratio range of a particular bike, we’ve calculated them and have them available in each bike’s individual review.
7. What Makes a Bike Easier to Ride (Q-factor)?
The Q-factor of a bike is the distance between the inside edges of the pedals. If the pedals on a bike are far apart, kids have to splay their legs out to pedal, which is inefficient and often uncomfortable.
When pedals are close together, kids can pedal without splay, providing an easier and more efficient pedal stroke. The smaller or younger a child is, the more important the Q-factor is.
We have yet to find a budget bike with a narrow Q-factor. Q-factors are rarely provided by bike manufacturers, but with smaller bikes we always list them in our product reviews.
8. Chain vs. Belt Drive
From stained pants to sticky fingers, bike chains can be a pain. They fall off, are hard to get back on, and when you do get them back on, they often fall off again. With a goal to simplify a child’s bike without sacrificing performance, Priority Bicycles uses a grease-free and maintenance-free belt drive on all their bikes (both child and adult!).
With no need to grease or clean, and with little, if any, chance of the belt coming off (we’ve NEVER had a belt come off), belt-driven bikes make bike ownership easier, cleaner, and more simple.
The rounded teeth on the belt and cogs also increase the overall safety of the bike. This is especially important for younger riders who often want to explore their new bike while it’s laying on the ground.
9. What’s the Best Brand of Kids’ Bikes?
With countless combinations of frame design, wheel size, construction, and components, the best bike or bike brand for any particular age simply doesn’t exist. Bike brands that build their bikes with kid-specific parts will generally always be better than bikes found at Walmart or at the local bike shop.
10. How Much Should I Spend on a Kid’s Bike?
In the end, price (and your budget) is going to dictate your decision quite significantly. More expensive bikes are almost always going to perform better than cheaper bikes, but as long as it’s safe, any bike is better than no bike.
Buy the best bike you can afford. Do not be discouraged if you can’t afford the top rated bikes on this site, but also be patient with your child when learning to ride on a less-than-ideal bike. More often than not, a bike’s geometry and design cause more delays in mastering a pedal bike than a child’s effort.
If your budget is tight, always consider buying used. The first kid’s bike we ever bought was an old Specialized Hotrock we got off of Craigslist for $30. It took a lot of elbow grease to get it up and running, but once we did it lasted our kids for several years.
Also, be mindful that kids outgrow their bikes within a year or two, but purchasing a larger bike that they will grow into will likely only delay their ability to truly master and/or enjoy riding.
Which bike is best for your child?
Now that you know what to look for, head over to our Kids Pedal Bikes: Comparison Charts for help finding the bike that best matches your desired features, your child’s age and inseam, and your budget.
- Kids Bike Sizes Guide – A NEW Trick to Finding the BEST Fit: An easy-to-understand infographic breaking down kids bike sizing
- Training Wheels: 10 Frequently Asked Questions: If you’re considering training wheels, read this first!
- 10 Best Kids 16 Inch Bikes: A comparison of over 20 different 16″ pedal bikes.