BALLS BY THE RULES
eleven sports at true relative size — circumference, mass, pressure, and who sets them
Free
BICYCLE CLASSES
frame, wheel by ISO 5775 and handlebar — three signs of a class, and what the frame is rated for
Free
CAR CLASSES
segments A to F by length and bodies by box count — how to name any car you see
Free
MOTORCYCLE CLASSES
rake, trail, wheelbase and seat height — six classes drawn at one scale
Free