two bikes of the same size

Kids Bike Size Guide

Which size Bike infographic

Which Kidvelo bike is right for your child ?

A Kidvelo Balance Bike is sized based on their wheel diameter, i.e. Rookie 12, Rookie 14 or Rookie 18

All our balance bikes require you to know your child’s inseam. This will allow you to select the correct size bike, while allowing some future growing room

Please bear in mind your child has to be able to sit on the bike seat, having both feet flat on the ground, with a slight bend in the knee




How to measure inseam

1. How to measure a child’s inseam

Tip! – Measure their inside leg/inseam with shoes on.

Measure your child’s INSEAM. Leg length is critical when gauging the correct size of bike. Please don’t just size a bike by the age of your child. Everyone is different!

The fit: Remember a balance bike is different to a pedal bike as children’s feet need to touch the ground. When sitting on the bike, kids this age should be able to put both feet flat on the ground. This helps children learn balance quickly and prevent tip-over accidents.

  1. Stand the rider straight against a wall
  2. Put a book between their legs
  3. Measure from the top of the book straight down to the floor
  4. That is your child’s inseam
Child on Rookie 12

2. Bike Weight needs to be in proportion to the rider

Experts recommend bikes shouldn’t be more than 30% of your child’s weight.

Heavy bikes over 4 kg will prove challenging to manoeuvre. Young children get frustrated easily. We often hear, “my child doesn’t like their bike,” and when we delve deeper, it is because they have a hefty steel bike with incorrect geometry or stabilisers.

Choose the lightest you can afford without eliminating all the features that make it comfortable to ride.

The Rookie 12″ is 2.89 kg and can be handled comfortably by the smallest riders. The Rookie 14” is just 4.7 kg without pedals or 6 kilograms in pedal mode.  Kidvelo Bikes are made from top-quality 6061 aluminium alloy to keep the weight down.

12 Wheels lying on the grass

3. Consider which size wheels you need

A 10″ wheel may allow for a lower starting seat height, but check the seat height range to get some years’ use out of it.

A quality 12″ wheeled bike may still achieve low seat positions, but the bigger wheel avoids speed wobbles.

Older children need bigger bikes, so consider a 14” or  18” bike.

If the child is a beginner, then a 2-in-1 bike is perfect as you get the benefit of learning in balance mode before converting to a bike with pedals.

Rookie 12 Tyre

4. Tyre Types

Tyres play a crucial role in the performance and comfort level of a bike

The type of tyres will determine the smoothness of the ride and the traction achieved on various surfaces. There are four types of tyres used. These include foam, air, plastic, and rubber tyres.

Pneumatic tyres give the most cushioning and traction and are considered the best all-around solution. Foam tyres are cheaper, lighter and generally puncture-proof. However, they lack traction, something we have witnessed firsthand in off-road riding. Rubber tyres are pretty solid, puncture-proof, and have better traction than foam tyres which aren’t comfortable over rough terrain. Plastic or EVA polymer is the lightest but lowest quality and typically only lasts a year. However, 12-inch pneumatics will offer longevity, far longer than a plastic 10″ wheel.

All Kidvelo Bikes come with Alloy rims and pneumatic tyres, perfect for any terrain riding. Our performance wheels are strong and very light.

5. Brakes or Not ?

Balance bikes work by using feet, safely placed on the ground, to move the bike along and to stop. There is a tendency when buying anything, to think that more features offer better value. When choosing for young children, the easier the bike is to use, the more successful they will be.

Brakes aren’t a good idea for young child as they will stop with their feet, which is intuitive and the safest method. Our experience has shown us that having lever brakes confuse young kids. They don’t know what to pull or they don’t have the finger strength to pull them so the child doesn’t stop quickly enough.

We also noticed that the reach on some brake levers isn’t adjustable enough. Worryingly, we have witnessed the kids taking their hands off the handlebars to pull the lever. For this reason, the Kidvelo 12″ balance bikes do not have brakes. Kidvelo Bikes for 3-year-olds and older do have brakes.

Child riding a balance bike with feet up on the footrest

6. Do you need a footrest or deck ?

Our bikes come with a footrest, so feet can be placed correctly when the child is balancing. When just starting out, the child won’t be lifting their feet far from the ground. As the child gets more experienced, they start lifting their feet for long periods of time. This is when the footrest is useful. If you ride your bike, then you wouldn’t ride off a curbside or over a bump with your feet dangling in the air. You would have your feet on the pedals and take the knocks in your legs. If you have feet in the air, it’s your bottom that takes the judders and it’s painful.

A footrest allows children to place their feet when coasting and balancing. Our footrests are designed to be in the correct position to mimic where the pedals will be, and in the convertible bikes, it gets swapped out for the pedal kit. Children are learning balance in the correct position to ride a bike from the start.

Rookie 12 Geometry

7. Geometry is Important

Suitable bike geometry will work with the child to help them learn to balance and manoeuvre, whilst a bike with poor geometry will work against them.

Learning to balance is done by walking, running, and gliding. It’s natural for kids to lean forward when running. But to be able to do so, they need plenty of room.

That said, you need to consider geometry that creates more space between the handlebars and seat post—making it easier to extend the legs for a more comfortable and natural run style while striding. It also means that the handlebar reach is still correct as the child grows bigger.

Watch the step-over height. A low step-over frame is much easier for children to get on and off. On the other hand, some bikes have a very high frame exactly where the child needs to get on and off, making it more difficult. Cyclesprog explains what they love about our design.

The same balance bikes work for girls and boys. Kidvelo Bikes have a low step-over frame making them easy to mount.

Rookie 12 Adjustability

8. Adjustability

All bikes in the Kidvelo range have quick-release clamps to adjust the seat height, and a scale marked on the post so you can easily fine-tune as children grow. Handlebars that you can set for near or far reach and adjust the height. Our grips are scaled for little hands to give the rider complete control.

Don’t make your purchase based on age alone. There can be a huge difference in leg sizes/inseam between children in the same age group.

Seat height-adjustability is crucial so that the bike will last a few years. When buying balance bikes, you need to check the seat height allows for a slight bend in the knee when feet are flat on the floor, allowing the bike to be walked or run along.


9. Choose the bike to match your child’s size & ability level

Don’t stress this bit. Our experience has taught us what approximate age children pick up the varying skills required to ride. Kidvelo bikes are sized correctly and consider what skills each age group can handle confidently.

Really young children should start on the Rookie 12 bike without pedals, brakes or stabilisers.

The Rookie 14 (a convertible pedal bike), has front and rear brake levers and transforms into a pedal bike by installing the included pedal kit. Ideal for those moving off their 12″ or just starting to learn at 3-years-old plus.

Older children will need the Rookie 18 version as it is bigger again.

10. Transitioning onto pedals

The rider needs to be comfortable with the weight and handling of their balance bike before transitioning to pedals. At Kidvelo, we make this process simple by giving you a larger, slightly heavier bike that you can use without pedals fitted to start. Get used to the increased weight and size and start learning how to use the brakes.

Once your child has mastered balance, our unique conversion bike converts to a pedal bike with the easy-fit pedal kit.

Why buy two bikes when you can have the next generation of kid’s bikes with the Rookie Convertible Balance to pedal bikes. (Arriving Autumn 2022). This design gives your child the best chance to learn balance without the complications of pedals.

If they aren’t ready and you need to go back a stage,  you can easily remove the pedal kit again.

Rookie 12 Award Winning

Rookie 12

For riders 18 months to 5 years old
Sizing a 14" bike

Rookie 14

Balance or pedalling
For riders 3 - 6 years

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Don't just take our word for it

  • Kazzi
    6 months ago

    Can't get over the quality of this bike, for the price its phenomenal. All the essential features have been carefully considered and included. I especially like the footrests and reach adjustment the bars and stem enable. Height adjustment is easy and the seat post has measurements too which is really helpful. It's so light a 2-year-old can lift it easily. It was so quick and easy to assemble my 7yo built it with minimal guidance. It's a really good looking bike with good quality robust components. I absolutely love it!

  • Liz Chambers
    5 months ago

    What a fabulous little bike. Bought for my niece as a Christmas present. She is 16 months and absolutely loves it. The bike arrived well packaged, instructions were clear and an absolute bargain for the quality. Thank you so much!

  • Hayley
    4 months ago

    My 3 year old loves his Kidvelo Rookie 12. This is his 1st bike and he's taken to it like a duck to water. He is so confident with it and obviously feels safe. The bike is very fairly priced, it was delivered quickly, its lightweight, easy to put together, and the quality is fantastic. My little one loves the chunky wheels and the bell too. I would definitely recommend this bike to anyone who is looking for their child's first bike.

  • Susan Abbott
    3 months ago

    I have recently purchased the Kidvelo Rookie 12 bike for my 3 year old granddaughter. The first thing to note is the website was very easy to use, delivery was quick and within an advised 1 hour time slot.

    The bike was packaged well and was simple to assemble, completed in under 10 minutes with all the tools required provided in the box. The first thing my granddaughter noticed was how bright the colour was, she loved it. After adjusting the seat height to suit she felt comfortable on the bike and couldn’t wait to get started. We took her to the local park and she where she just understood naturally how to use the bike and required limited guidance. Seeing her on the bike after just a few trips out I believe she will get much enjoyment out of using it and set her up perfectly for moving onto the next step.

  • James Kennedy
    1 month ago

    I don’t normally leave reviews, but I’m so impressed with our recent purchase of a Kidvelo bike that I thought this product was worthy of one. The first thing we noticed was the build quality of the product. It’s well made and really sturdy when put together. The black wheels and tyres look great and my little one loves the bright pink colour! I only wish I’d have known about this bike sooner as I would have bought one for my son, who seems to enjoy going on his little sisters bike more than his own! Thanks to all at Kidvelo for making a little girl really happy!

  • Ellie Gentleman
    1 month ago

    Highly recommended Kidvelo Bikes Uk.
    We have the Rookie12 for our little boy. The bike feels super sturdy but lightweight for me to carry around where ever we are going! Super easy to put together my little man even got involved helping me put it together.
    My little one likes the extra features of the foot rest for going down little hills this also really helps with his balance for when he’s ready for the next size bike up.
    As a parent all the extra features with the handle bars and seat as they grow with him so I’m not having a buy a new one weekly is brilliant! “he don’t stop growing “😀
    Also the communication with Kidvelo Bikes Uk was Fantastic and all my questions answered.

  • Nick Jeggo
    3 weeks ago

    A Revelation!
    I work as a cycle instructor delivering Bikeability, Learn to Ride and led rides in the Town Park. I'm also the British Cycling Go-Ride lead at my cycling club. The club has been using a Rookie 12 to help keep younger siblings happy while brothers and sisters attend our sessions.
    The bike has been amazing, a revelation in fact. First of all, it's incredibly light, something that everyone comments upon. In fact, when the bike arrived we wondered if the box was empty!
    The steering has proper bearings, as do the hubs, so everything runs really freely. The MTB type handlebar stem is adjustable and the handlebars are shaped so that the reach can be tailored to the rider. The tyres are proper 12" pneumatic with Schrader (car type) valves and the relatively smooth tread pattern means there's the perfect combination of low rolling resistance and grip. There's a choice of 4 colours, but we have the bright green. You certainly can't miss it!
    I've come across lots of balance bikes, but this one stands way above anything else I've seen. You may find some of the features on other bikes, but the rookie 12 has them all in a brilliantly designed combination.
    Buy quality, your kids will thank you for it!

  • SheLovesBarney
    2 week ago

    I bought a Kidvelo Rookie 12 for my cousin. It’s incredibly light and the quality is fantastic. Delivery was free and the bike arrived the next day. Well packaged and easy to assemble. I totally recommend this bike for kids just starting out.

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