As above.
Fitted new belts last year without any subsequent problems, but about a month ago i noticed the AC belt missing, installed a new one and it snapped within a few days. Did the same again this weekend.
I have this rubber deposit where the belt seems to be rubbing against the bracket that holds the tensioner pulley, But when inspecting the belt it does not seem to be touching at all? I inspected the tensioner pulley at is seems ok, but i will replace it if that's what causes the problem?
They are installed and tensioned correctly. Any ideas what would cause this?