Avon Tyres has put up a website section specifically for motorcyclists, and there’s information on it that could be useful.
The "motorcycle" tab on the avon-tyres homepage gets you to a place where all Avon motorcycle tires are described, and technical information on tire construction, reading sidewall information, and tire sizes can be found. There’s a "Rider" section where special information is available. For instance, under the "Safety" heading, there’s a note that tires used in a dyno test will no longer be covered by the manufacturer’s warranty — didn’t know that, did you?
There is some useful information on the site, but there’s a lot of wasted space, too. Arlen Ness, for example, gets his own page, and gets to tell you that he uses Avon Tyres because "they are available in some of the monster sizes we need for some of the more far-out conversions."
Lame, but perhaps useful at times, and if you’ve got a bike with an odd-sized wheel, it’ll help you find something that fits. www.avon-tyres