Kids Bike Sizing Explained - How to Compare ByK Bikes with Traditional 12", 16", 20", and 24" Kids Bikes

Whether you are researching kids’ bikes for the first time, or looking to upgrade a bike to the next size, you’ve probably wondered why are children’s bikes usually categorised by 12", 16", 20", or 24”, and why are ByK Bikes not?

Categorisation of kids bikes by wheel size in inches

Kids bikes have, for as long as we remember, been categorised in the older, imperial system by measuring the wheel size in inches. Oddly, this dated ‘inch-sized’ measuring system is a little misleading, as the true size of the wheel is often quite different. For example, 16” translates literally to 406.4mm. However, a typical 16" wheel size bike you’ll find in stores today has an actual rim diameter of 305mm! This is probably because over time, wheel size choices at the manufacturing level have changed, but the customer expectation of a category system they were used to didn’t, so bike manufacturers decided to stick with it.

Why are ByK bikes not categorised in inches?

When we started ByK Bikes, we wanted to change the way we looked at kids bikes and really innovate the design. So, to begin with we went metric - we’re an Australian-based company so it made sense. And we wanted to be consistent with the next generation of parents and kids who were looking for a better kids bike, and not be bound by old, out-of-date traditions. So we took a fresh look at kids bikes with their overall design and the ergonomics of a kids growing body. This was more than just changing over to metric. We increased the wheel size for better dynamics and rolling efficiency. Thereby creating our own, new category system, ignoring traditional wheel size altogether. Explaining how to compare ByK Bikes to traditional kids bike sizes is not as simple as saying that we increased the wheel size. Increasing the wheel size of a kids bike, and introducing a low centre of gravity design, is just a small part of our total ergonomic concept. Our unique design is why Scienceworks included us in their exhibition, alongside a raft of Australian inventions such as the black box flight recorder, the polymer bank note and the multichannel cochlear implant, that explored themes of innovation and inventiveness. Read more about that Scienceworks Innovation exhibition here. And to understand all the design innovations of the ByK Kids Bikes, read more here.

byk_comparison_with_text ByK E-250 compared to a traditional 12" kids bike

e-450-reveiwzoo-bike-compare-2 A good example of comparing two kids bikes that are both designed for kids between 5 and 8 years old. This photo is courtesy of

Comparing Kids Bikes by Wheel Size Categorisation

We've made it easy to compare ByK bikes against the standard imperial-categorisation of bikes - just look at the table below. For example our E-350 bike is intended for the same rider who rides a traditional 16" bike, but we use an 18" wheel, or 350mm metric size wheel that is comparable on an 18” bike. ByK Kids Bike Sizing Infographic Guide So we’ve named our models as close as possible to the actual metric measurement of the wheel - a naming system that reflects the true wheel size of the bike. It just makes sense. This article was written by Warren Key, owner and designer of ByK Kids Bikes, Father of 3, and over 40 years experience working in one of Australia’s oldest bike shops. Learn more about Warren and the ByK Story. kids-bike-sizing-guide-1200x628-web