- They are easy to whip on and off over your shoes.
- Repel rain from the most exposed areas - your bum and thighs.
- Avoid 'chain suck' at your ankles.
- Minimise overheating when pedalling hard.
However full-length over trou are sometimes best - notably for commuting when you want to keep your long pants dry, or when touring to really cold and/or wet places.