This is the distance between the pedals. Kids need a narrow Q-factor so their legs aren't splayed out like a duck.

Aluminum frames are significantly lighter and easier to handle than steel. 🛑 3. Braking Systems

Height 3’1” – 3’7” (Approx. ages 3–5)

Higher price, but the bike is professionally assembled, safe, and often comes with free tune-ups.