Weight, Gearing, Fit for Family/Purpose.  Weight – Your child isn’t as strong as an adult – or even a teen  – give them a hand and allow them to ride something light.  Recently in a school program we came across a bike that was 22.5kg, now considering the 11yo owner  was approx 40kg, this bike was more than half his body weight – think of yourself having to ride such a bike. It will be hard and the child will struggle and COMPLAIN – go lighter weight for your sanity!! A VERY loose rule of thumb that I’ve worked out…