The main difference between rollerblades and roller skates is the number and arrangement of the wheels. Roller skates always have four wheels that are aligned in two rows. The rubber brakes are arranged in front of the wheels. On the other hand, rollerblades may have three, four, or even five wheels on each skate. The wheels are usually thinner than those on roller skates and the rubber brakes are placed in the back, behind the wheels. Rollerblades also have larger wheels than roller skates, so they’re much faster and a better choice for speed skating. “Most inline skates use a hard outer plastic shell that comes up above your ankle and that provides a lot of lateral support,” DeLong says. “In contrast, roller skates are usually made of leather and come up just above or even below the ankle, giving the skater more ankle mobility which can be helpful for certain styles of roller skating.”