Originally Posted by
aubinmg
Seems like a bad idea to me. Capes are fine if you're walking, on the bike they will flap and flop and get caught of stuff. They MAY keep your shoulders dry but that would be all. I recommend and use a waterproof breathable jacket.
This is incorrect.
Bike capes have straps that loop around your seat post. Also, the front has straps to put your hands in. So you stretch the cape out from the handlebars to the seat. That keeps your upper torso very dry, with plenty of ventilation under you. It works great. The wind comes into play to knock the cape around below your waist. That can cause you to get wet on the sides or front of the bottom of your legs.
Note that if you intend to ride fast in the rain this isn't the best bet. The cape acts like a sail and slows you down a bit. I wouldn't do without one, but I can see some that those who enjoy a big ride in the rain need a different product.
FYI--you'll still get wet from underneath if you don't have fenders.