🚲 Bike Tire Sizes & Their Uses – Glolink Bicycles 12 inch 🧒 For toddlers (2–4 years). Balance bikes & starter bikes. 16 inch 👦 Kids 4–6 years. Slightly bigger, often with training wheels. 20 inch 👧 Kids 6–9 years. Also common in BMX bikes. 24 inch 👫 Pre-teens (8–12 years). Smaller MTBs and junior riders. 26 inch 🔹 The classic adult MTB size, versatile for city trails. 27.5 inch (650B) ⚡ Popular MTB size. Balances speed (like 29") and maneuverability (like 26"). 29 inch 🏔️ Larger wheels, f