How Motorcycle Tire Sizes Work (90/90-18, 3.00-18, 110/80-17)

Two common formats

• Metric: 90/90-18 = width 90mm / aspect 90% / rim 18”
• Inch: 3.00-18 = approx width 3.00” / rim 18”

Quick rules that prevent mistakes

1. Keep rim diameter the same (18 means 18”).
2. Check rim width range and clearance for wider tires.
3. Load & speed rating matter for high-speed use.