Rear tire of motorcycle Scorpion Rally of the company Pirelli. It is suitable for sport driving, meaning it is designed for use over long distances and at high speeds.

Its dimensions are 90/90-21. That is, it has a width of 90mm, a profile of 90, and can be mounted on a 21" rim. The profile in tires, meaning the height of the tire's sidewall, is always referred to as a clean number without a unit of measurement as it is a percentage of the width. For example, a 180/55 tire has a width of 180mm and a profile of 55, meaning it has a profile of 180 x 0.55 = 99mm.

The TT marking comes from the initials of the words Tube Tyres. Tires bearing this marking require an inner tube.