I wish I was closer to completion on a write-up I am working on about tires. To boil it down as best I can the ST1300 needs to be fitted with a 120/70ZR18 (59W) front tire and a 170/60ZR17 (72W) rear tire. That simply means that Honda had the companies change something in the tire from the generic perduction tire. But either tire will still have to comply with the fitment listed on the Federal sticker. Tires are manufactured to certain specifications dealing with size, load capabilities and speed rating. They also use different compounds in the tread to gain traction or extend longevity. As many have reported certain tires have certain ride characteristics and life expectancies. The bottom line is simply this. If the tire meets the specifications listed on the sticker on the left side of the frame neck then it would be considered safe for the bike.
Tires are built and certified to carry the weight at whatever the speed rating is and it's molding into the sidewall. The tire manufacture may or may not have tested each tire on every possible bike, or car for that matter, but it doesn't mean that the tire is not approved because they haven't.
New tires lines are released before testing can be done on all vehicles or may never be done, their choice. But before they can be released for sale they have to under go testing for their specified rating. So if you are worried whether or not a certain tire is safe to use on the ST1300 check the specifications. If it is listed as a 120/70ZR18 (59W) or a 170/60ZR17 (72W) you are good to go. Whether or not you are happy with the tires performance is a totally different story.
I like several others on this site have bought new tires that were not in the tire manufactures online fitment charts. Also, in todays litigious world do you think a company is going to say a tire is safe to use on a vehicle that they have not personally tested it on? But they won't hesitate to sell it to you so go figure.
Personally I feel the new Avon Storm ST's are a better tire than the Azaro line they replaced. I only have about 1,500 miles on them though so desired life expectancy is still up in the air.
The bottom line is
YOU have to be comfortable with your
DECISION.
Happy Shopping!