As a preventative measure, I just changed the alternator belt on my bike at 45,000 km, using the adjustable wrench technique that I saw on a youtube video. I have driven about 400 km since, and so far, so good.

What I am kind of wondering about however is the following statement, excerpted from the BMW Repair Manual DVD for the bike:

"If it is not correctly installed on the pulleys, the belt will suffer irreparable damage within a very short space of time.

Make sure the belt is installed right way round."
Emphasis mine.

I am wondering what they mean by "right way round"? I mean...the belt isn't directional (like a tire) it? I couldn't find any marking on either the original belt (which, upon removal, looked to be in perfect condition by the way), or on the replacement belt, that would indicate that it is supposed to rotate in one direction or another.

Are these belts directional?