The Ultimate Guide to Buying a Kids Bike

1 July 2020

Frog Bikes Ultimate Kids Bike Buying Guide

We hope you enjoyed our previous blog detailing how to size your child and make sure you purchase the right-sized bike for them. This follow-on post takes you through the bike buying process in a little more detail; to help you recognise what to look out for.

Like any important purchase, long spec lists can be quite daunting and it’s hard to see the wood from the trees sometimes. The following information will help you to understand what is important and what is simply nice to have.

Our first tip for finding the perfect bike is to do your research before you go shopping! A good quality bike can be an expensive purchase so it’s important to know exactly what is important to you. Like any big purchase if you pay a little more the quality will be infinitely better, after all, a good bike can be passed onto siblings and will have a much higher resale value.

In our first Ultimate Buying Guide we will explore the following topics - The Frame, Geometry, Q-Factor, Handlebars, Gears, Shifters, Componentry, Brakes, Tyres, Safety Features and Added Extras.

The Frame


If you only have one criterion when purchasing a bike you should choose the weight. A lot of the cheaper bikes available are really heavy, some weighing in at as much as 50% of a child’s body weight. It’s not unusual to find that some children’s bikes are heavier than an adult bike! Imagine trying to pedal and manoeuvre a bike that is half your body weight, that doesn’t sound like fun to us.

It’s also worth remembering with Balance Bikes and even a first pedal bike, if they get tired or decide they’ve had enough, it will be you carrying the bike back home!

The majority of kids bike frames are made from aluminium, the frame material is a good place to start and the first thing to check. There are manufacturers producing children’s bikes using steel frames which are likely to be heavier and titanium frames which will be quite costly.

There can still be a variance in the quality of bikes made from aluminium. Like many materials, there is high and low-grade aluminium, so do check the overall weight of the bike to ensure it is lightweight. You can find up to 2kg difference in weight between 2 different bikes that both have an aluminium frame just because of the quality of metal and components used.

Whilst aluminium and titanium frames will be the lightest if you find a steel bike with good quality, lightweight wheels and components, a steel bike can still be a good option. The main thing to note with steel is that it will rust if not protected. If left outside and unprotected, steel frames, seat posts and bolts will corrode far quicker than aluminium.

From an environmental stance, by making bikes using high-quality frames and components we can ensure that our bikes are handed down through families or sold to new families and do not end up in a landfill site. One of our current research projects led by Shelley Lawson is centred around how we can recycle and reuse old aluminium bicycle frames.

Frog Top Tip: Look for a bike that is less than 40% of your child’s overall body weight


In our sizing blog post, we discussed the lengths we went to, to ensure we created a frame with the geometry to put children in the most comfortable and efficient riding position.

One aspect you can look at if you want to explore a child’s bikes geometry chart is the Wheelbase - the measurement between the two wheels. A longer wheelbase creates a more stable bike, allowing the child to have complete control over the bike when riding.

Bikes with a shorter wheelbase and higher centre of gravity will be harder to ride and feel very unstable. This can cause the child to lose their balance regularly and ultimately their confidence too.

Frog Top Tip: For a more stable and balanced ride look for bikes with a long wheelbase


This is a confusing subject but the best way to understand the Q-factor is to see it as the distance between the 2 pedals. It is officially the distance between the outside of the left crank arm to the outside fo the right crank arm (taken from the point on the crank at which the pedals are installed).

An adults hips are wide enough so that their legs will remain straight when their feet are on the pedals. But smaller children have narrow hips - if the Q-factor is too high a child will have to splay their legs outwards in order to pedal. This will feel really uncomfortable for them and can lead to an injury.

You want to see their legs in line with the bike frame, allowing them to pedal comfortably and efficiently. If the bike has a lower Q-factor then this will be what you see.

A reduced Q-Factor is only possible with speciality parts, such as our patented FrogFit cranks which have straight arms to reduce the Q-factor further. It is unlikely to be on a budget bike due to the speciality parts, but this is definitely worth putting on your checklist.

Frog Top Tip: Pick a bike with a reduced/smaller Q-Factor


The 3 main styles found on kids bikes are High-rise, Mid-rise and Flat handlebars. All Frog Bikes are produced with flat handlebars to provide a natural cycling position, which is a slight lean forward in the child's back - around 65 degrees. If your child prefers to ride in a more upright position we offer a handlebar riser which will raise the height of the handlebars and allow them to sit upright.

Mid-rise bars can offer more height but do check there is plenty of space for their knees, that they do not hit the handlebars when turning and they allow the child to lean slightly forward.

Bear in mind, handlebars that are too high or sweep back can sometimes cause a backwards lean, put a strain on the neck, prevent the rider from applying force on the handlebars and impact the bikes manoeuvrability.

For riders that are just learning, being able to lean towards and apply more pressure on the bars allows them to attain a much better pedalling position.

You can also check if they are able to reach the handlebars. When sat on the bike can they comfortably grip the handlebars without fully extending their arms?

Frog Top Tip: Flat or Mid-Rise handlebars offer the most natural and stable riding position

Componentry Used on Children’s Bikes

Gears of Single Speed?

Most first pedal bikes will be single speed, these are less complicated and it’s good to remember, smaller children don’t always need gears, they can be confusing and add unnecessary weight. It is best to avoid gears until you are looking at a second bike once pedalling, steering and braking are second nature.

However, a single-speed bike will be harder work to pedal uphill, if you live in a particularly hilly area then gears suddenly become very important. One way to decide if your child needs a bike with gears is to watch how they ride uphill. Are they struggling, pushing the pedals around really slowly, do they get off the bike completely and prefer to walk? If the answer to these questions is yes then you should look for a bike with gears if possible.

Once you are starting to tackle hillier rides together we recommend starting simple, with a single chainring on the front. A bike with a triple chainset with upwards of 21 gears will confuse a younger child.

A geared bike requires regular maintenance and more looking after than a single-speed bike, this is due to it having a shifting mechanism called a rear derailleur on the rear of the bike. Derailleurs can be damaged easily causing the gears to stop changing smoothly, maybe even completely.

If you decide to go with a geared bike, choosing a single chainring on the front will mean that the bike will only require one shifter, for the rear derailleur. One shifter is much easier for kids to master, they can get to grips with gearing, shifting up and down, without having to worry which shifter/lever they should be using.

Frog Top Tip: Learning to ride is easier on a Single-Speed bike but if you live in a hilly area or they are already a confident rider then go with gears

How Many Gears?

Kids bike gears can range anywhere from 7 to 24 gears depending on the number of chainrings on the front (single/double/triple). You might see bikes labelled as having 8, 16 or 24 gears, this will all depend on the front chainring. If a bike has one front chainring and 8 sprockets on the rear cassette the bike has 8 gears. If there are 2 chainrings on the front and 8 sprockets on the back the bike will have 16 gears, and so on.

To further understanding gearing, we need to look at gear ratio. Gear ratio is the ratio between the chainring size (at the front) and the cassette size (at the back). The difference in gear ratios on kids bikes can be small but it will make a big difference regarding how easy the bike is to ride.

A High ratio requires a little more effort to get started but the bike will travel further with every push on the pedals. This is better for flat riding. A Low ratio makes it easier to get going but they’ll need to spin those pedals a lot more to travel further or faster. This is better for hilly riding.

A ratio of 4 would be considered high and 2 would be low. Bikes with a ratio of 4 will be much harder to ride up steep hills than bikes with a ratio nearer to 2. Consequently, older or stronger children will be more comfortable riding a bike with a higher gear ratio.

Frog Bikes are built with components that allow for a lower gear ratio on our smaller bikes, ensuring they are easier to pedal and learn on, then as our bikes get bigger (and the rider is older and stronger) the gear ratio increases.

Gear ratios become even more important when your child is riding a road or mountain bike as they will encounter a greater range of terrain.

Frog BikeFront ChainringRear CassetteGear Ratio
Frog 40 (First Pedal)32181.8
Frog 55 (Hybrid)32112.9
Frog 73 (Hybrid)34113.1
Frog 70 (Road)34 / 42113.1 / 3.8
Frog MTB 6940113.6

This table shows an example of Frog Bikes gear ratios.

Shifters: Grip or Trigger?


Gear shifters can be surprisingly difficult to operate for kids. A sign of a good quality bike will be child-specific components that are made to be used by smaller hands.

The two main types of gear shifters are Grip Shift and Trigger shifters. Grip shifts are activated in a twisting motion, you just twist the grip forwards or backwards with your hand. Trigger shifters are activated by a lever, pulling or pushing on the lever with your fingers changes gear.

In the past grip shifts were the preferred shifter for kids bikes but they can be difficult to operate and not always as robust. We favour trigger shift on our bikes, with the FrogFitTechnology™, child-specific levers making it easy for little hands to change gear. As most adult bikes have trigger shifters it is good to get used to them early.

Last year, as part of a funded Innovate UK project, Frog Bikes scientifically analysed the Shifters on our Frog 52 and 55. Our research uncovered that the long, lever travel was a more apparent constraint for younger children than a lack of finger strength when operating the shifter.

In July 2019, we introduced the new FrogFitTechnology™ Shifter reducing the distance the lever has to travel by 65%, bringing a major improvement to our bikes. Smaller children can now shift to lower gears more easily, allowing them to focus better on the road ahead and having fun on the bike!

Frog Top Tip: Teaching your child to always put their bike down with the gears and chain pointing upwards (not touching the ground) or using a kickstand, will be a massive help in keeping their gears working well

Quality Componentry

The drive train is the group of parts that allow the bike to move and change gear. The components that make up the drive train are the cranks, chainrings, chain, cassette and rear derailleur. The higher quality these components are the fewer problems you will have with the gears getting out of tune.

If a rear derailleur or gear shifter isn’t working properly, you may find that you will only be able to use a couple of the gears. When you try to shift to the other gears the chain could come off or it will try to move unsuccessfully, causing the bike to make a loud noise when you try to pedal.

There are a few manufacturers out there offering kids bikes with internally geared hubs. This simply means that instead of the chain moving up and down a cassette to change gear, this all takes place inside the hub on the rear wheel.

Although we mentioned at the beginning of this post that lightweight is imperative for kids bikes, it is here that we will slightly contradict ourselves!

When it comes to componentry some of the cheaper, lower quality components used on kids bikes can be lighter but this does not make them better! They are often produced from plastic that can break and aren’t child-specific. So, whilst it’s important to keep the weight down it is far more important to produce a bike with quality working parts that will allow it to be ridden and enjoyed for years to come.

We even use high-quality parts on Frog Bikes where you can’t see them. Our bikes are all produced with a professional level, Jagwire gear cabling as we found that this reduced friction when changing gear making it 35% easier for a child to apply force to the trigger shifter. It’s the tiny, unseen features like this, that we feel sets our bikes apart from many others.

Brakes: Rim or Disc

At Frog, even our Balance bikes come supplied with a rear hand brake to teach speed control from the beginning. We know the soles of their shoes will do a great job but starting to understand braking and control from an early age will set them up perfectly for their first pedal bike.

The 3 most common brakes found on kids bikes are rim, disc and coaster brakes. These can be split further into types of rim and disc brake but we’ll come to this later!

It should be quite easy to ascertain what system a bike has by just looking at the bike. Rim brakes attach to the bike frame and will apply pressure to the rim of the bicycle wheel. Disc brakes will have a large disc in the middle of the tyre with 2 pads either side which apply pressure to the disc rather than the wheel itself. Coaster brakes (sometimes called a foot brake) are a little harder to spot as they are part of the wheel, the absence of hand brake levers is the one way to tell if a bike has coaster brakes.


The 2 most common rim brake systems on children’s bikes are Single-Pivot (Side Pull) and V-Pull (also known as Linear Pull).

Single-Pivot brakes are more likely to be found on budget bikes. When used on a wider hybrid tyre, as found on most kids bikes, they can flex resulting in poor performance. They are prone to coming out of alignment and tend to rotate to one side and stay there! This makes it difficult to space the brake pads evenly either side of the wheel rim.

Even when aligned correctly they have less stopping power than a V-Pull brake, it is not unusual to find bikes with Single-Pivot systems have a coaster brake for backup.

V-pull can be found on mid to high range kids bikes and are even used on many adult bikes too. They are easy to adjust, durable, keep their alignment and offer more stopping power than Single-Pivot brakes.


Instead of using the rim as the braking surface, a disc brake uses a metal disc mounted at the centre of the wheel. The metal disc rotates between a calliper holding 2 brake pads which are applied to slow down the bike.

They can be hydraulic - hydraulic brake fluid in hoses is compressed to move the pistons and pads, or mechanical - where the pistons are engaged using a cable. Hydraulic brakes are seen as more effective but mechanical disc brakes have improved over the years and are easier to maintain.

Disc brakes tend to only be applied to kids Mountain Bikes or older children’s hybrid bikes. They will add weight to the bike so unless you are riding somewhere especially muddy or need the extra stopping power they are not worth the additional weight or cost.

Coaster brakes

Coaster brakes are super simple, you stop the bike by simply pedalling backwards rather than using a brake lever on the handlebar. They can be a little bit like ‘Marmite’, kids either love them or hate them! Coaster brakes are likely to add extra weight and they will still need to learn how to brake properly with their next bike.

Coaster brakes are more commonly found in the USA and on cheaply produced bikes. This is because lower-cost bikes often have adult-sized hand brakes that children don’t have the strength to pull which makes the coaster brake necessary.

There are a couple of aspects that you should be aware of when it comes to coaster brakes.

You can’t pedal backwards. If a child tries to backpedal on a bike with coaster brakes the bike will stop suddenly causing them to fall over. Quite often the natural reaction when a child starts to lose their balance is to backpedal. If the bike has hand brakes they can freely backpedal and regain control but the sudden stop caused by the coaster brakes when they try to backpedal can be dangerous.

There is no modulation on a coaster brake, it’s on or off, they can’t feather the brakes to scrub a little speed off. If the brakes are applied when they are whizzing downhill there is a risk of skidding or the brakes locking up.

If you would prefer to pick a bike with a coaster brake then look for one that has a hand brake too. It’s far better for children to learn how to modulate their speed using a handbrake when they are younger.

Brake Levers

Brake levers come in lots of different sizes and it’s not unusual to find adult brake levers on a child's bike. It’s unlikely a child will be able to operate these as they will be far too big for them to reach and remember a child's grip is weaker than an adults'.

On well designed, high-quality kids bikes the brake levers are designed for smaller hands, you can test this yourself in a store by trying to squeeze the brake with just your little finger. If you can activate the brake with your little finger then it’s safe to presume your child should be able to activate them with their hands.

For a drop handlebar road or cyclocross bike, check if your child can operate the brakes when their hands are on the drops as well as on the top hoods. Our Frog Road bikes are all fitted with secondary brakes on the handlebars to help build confidence. Frog Top Tip: We would recommend hand brakes over coaster brakes and if you can, test the brakes by applying them using just your little finger.


Foam or Pneumatic?

Most children’s bikes are supplied with pneumatic (air) tyres but do check this. On Balance and First Pedal Bikes that are of lower quality, it is not uncommon to find them supplied with foam/solid tyres.

Foam tyres are low maintenance and claim to be puncture-proof, but only to the weight limit of the bike. They provide a lot less traction than an air tyre and are suited to very young riders who are light and only riding on paved surfaces.

Air tyres weigh a tiny bit more than foam, however, they come with an inner tube that can be replaced when you get a puncture so they last longer. Air tyres will have a knobblier tyre which provides more traction and grip allowing the bike to be ridden on rougher surfaces like woods, canal paths and trails. They also offer more cushioning as they absorb the vibrations when riding making it a much more comfortable ride.

Slick or Knobbly?

Air tyres come in 2 different styles with different types of tread.

Slick tyres are most suited to road riding, made for smoother tarmac surfaces they have a lower rolling resistance which makes them faster.

Knobbly tyres are better for off-road riding, they provide increased grip and traction but have a greater rolling resistance so they will feel slower and a little more sluggish on tarmac.

There is a middle man - Semi-Slick tyres. These have a small amount of tread but nothing like the tractor style knobbles of a pure off-road tyre. Semi-Slicks will have a better rolling resistance on the road but will only be okay off-road when it is dry. As soon as the ground becomes muddy and slippery the Semi-Slicks won’t offer much traction.

Frog Top Tip: Knobbly tyres offer more versatility, with these tyres a child can comfortably explore riding off-road routes and towpaths as well as tarmac

Safety Features

Frog Balance Bikes are built with an inbuilt steering lock. This prevents oversteer which can result in an accident.

It is also recommended to have
reflectors on the front and back of the bike. We would say the rear red reflector is the most important. Reflectors that fit in the spokes are a good idea for the front and back wheel.

Another item to look out for is a chain guard. They can be full guards which cover the entire chain or just a chainset guard. They will protect your child's legs and hands from the chainrings and chain and lower the risk of clothes getting covered in chain oil!

Bear in mind that full chain guards can be very fiddly to remove or replace if you need to do any maintenance to the bike.

Extra Touches

Easy Adjustments

Does the bike come with a quick release for the seat post? It’s inevitable that you will be making adjustments over time, especially at the beginning.

When they are first learning it’s best to have the saddle low so they can touch the ground with both feet. This can allow them to stop with their feet and increase confidence levels. As they progress, the seat post will need to be raised, at this point they will just be able to touch the floor with their tiptoes. This extra height allows them to pedal more efficiently.


Mudguards are a must in the UK! Especially if the bike is going to be used for the school run, we would highly recommend getting some. It can be tricky to find a good fitting mudguard for smaller wheeled bicycles so ideally, try to choose a bike that comes with its own specific mudguards.

If the bike does not come with mudguards included then check the frame, are there eyelets to fit mudguards. If there are not then you can use clip-on/universal options on a larger bike there are limited options for bikes with wheels under 26”.

Pannier Rack

Are there eyelets in the frame to attach a rack? Does the bike come with a pannier rack? If not is this something you can purchase at a later date? If you are planning to use the bike for school or a cycling holiday this will be really important to check.

Handlebar Riser

This is a handy little component that you can use to ensure the bike grows with your child. It attaches to the steerer tube of the bike and allows you to increase the height of the handlebars.

As your child grows and you raise the seat post you can find this causes a bigger drop to the handlebars which is uncomfortable but easily rectified with the Handlebar Riser. You can purchase this on our website here.

Frame Protectors

All Frog Bikes come with Tube Toppers. These strange little contraptions click onto the cables at the front of the bike, by the headset and prevent any rubbing on the frame which can damage the bike’s paintwork.

If your bike doesn’t have these, you can purchase clear, frame protection stickers from any local bike shop and just pop them on the frame where the cables can rub.


You are likely to get a warranty no matter what the price tag is on the bike, but the length of the warranty will vary.

Many manufacturers offer a warranty that covers the bike for manufacturing defects and often the frame itself will have a longer warranty than the components. One thing that is never included in a warranty is crashes!

Higher quality bikes tend to come with a longer warranty period. At Frog we offer a 2-year warranty on the components and if you sign up to our Warranty Plus (which is free) you will receive a 5-year warranty on the frame and solid forks. Having this longer warranty means that if you have a younger child you would like to pass the bike down to it is more likely to still be in warranty for any issues that arise.

Always read and understand what the warranty does and does not cover before you make your purchase.

Congratulations, You Made It!

There was a lot to cover here, but the better informed we are the better decisions we make. After all, choosing your child’s first bike could be the difference between them falling in love with cycling or being scared and hating every minute.

It is likely that your budget will ultimately dictate which bike you choose and although we have tried to impress the benefits of going for a higher quality bike, safety really is the main thing. If your budget is tight then do consider buying a second-hand kids bike. A high-quality bike that has been looked after can be as good as new, even after a couple of owners and years of use.

There is a lot to remember in this post so we have produced a handy checklist for you to download and work through the next time you're bike shopping, to ensure you get the best bike for your child.

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