Re-Designing Kids Bikes for Easier Pedalling

Frog Bikes has worked with independent scientific researchers to study the impact of Q factor (pedal spacing) on bikes for children. They were surprised to find that reducing the Q factor of a child's cycle decreases lateral forces by much more than for adults. i.e. it makes the bike significantly easier to pedal.

Frog has combined the Brunel University research and worked with Dimitris Katsanis of Metron Advanced Equipment (the man behind the all-conquering GB Team track bikes) to design new crank arms that reduce the Q factor by between 27mm and 36mm depending on the Frog model. These cranks are on all new Frog pedal bikes available in the market since June 2015.

The new bicycle cranks deliver a more comfortable ride and improve the efficiency for kids - who of course have a much narrower pelvis than an adult. Thus, for a child riding a bike with pedals conventionally widely spaced, the child's legs are splayed outwards to the left and right sides of the longitudinal axis of the cycle. This results in poor conversion of the work performed by downward movement of the child's legs into the rotation of the chain.

Other innovations in kids bike design that have already been introduced, as a result of the research, include even shorter crank length, a steeper seat tube angle and a shorter reach - all aimed at making a child's riding experience as comfortable and enjoyable as possible.

Jerry Lawson

Jerry Lawson, Chief Frog at Frog Bikes said: "Children are not just scaled-down adults: they have specific bike requirements which are not currently well met. We are applying the same rigour to the design of kids' bikes that are usually applied only to adult bikes. This means that Frog bikes are not only extremely light and well-made, they also incorporate unique research-led design features which make them much more comfortable for children to ride."

Dimitris Katsanis

Dimitris Katsanis said: "It has been a real pleasure to work with Frog Bikes on this project.  Although the ultimate aim of the research is to increase the fun that children derive from riding their bicycles it is nevertheless a serious piece of engineering with significant results.

This is more than a marginal gain. I wish we could find something similar for the Olympic bikes too.  And you never know, some of these children might end up being the Olympic champions of the future. "