Hi All:
I had an exchange by PM with another forum member about tank bags just a week or so ago and so I have clipped it out and inserted it here. Basically, I have always used a tank bag with my previous bikes but I really wanted to check the fit before I bought any new luggage because I was concerned that it wouldn't fit on the ST1300s oddly shaped tank.
It was also important to me that the bag not interfere with the handlebars and controls such as the starter button, horn and turn signal switches - and I have MCL Gen III risers which makes the potential for interference even worse.
After some experimentation, I went with a German-made (i.e. expensive but very high quality) SW-Motech tank bag which mounts using a tank-ring on the fuel filler flange. I got the whole setup from Twisted Throttle who have a distributor here in Canada as well as in the US. I went to their store here in Ontario and was able to test fit the bag so that I could confirm the fit and compatibility with the STs bars and controls. The Motech bags fit fine - no compatibility problems at all.
I have two SW-Motech bags - the smaller "DayPak" and the larger "CITY" model. I find the DayPak to be great for booting around on day trips and commuting because it is small and you can take it into restaurants etc. and the City is good on longer trips because it can hold all of my "minute-by-minute" access stuff like sunglasses, my phone, charger cords etc. and it has a detachable clear top map pocket.
The DayPak is small enough that it simply perches on the top of the ST tank while the CITY is quite a bit bigger and it goes from just ahead of the fuel filler to down just about the front of the seat. It is not intrusive at all and in fact, unless you actually look down, you might forget that it is even there until you need it. Both bags have a little cut-out in the front to allow an electrical cable to be led into the interior (for a phone charger for example) and overall, they are very very high quality products.
The tank ring is easy to mount using the stock mounting bolt holes on the top of the ST fuel tank (they provide new hardware) and you do need to get the correct ring for the Honda fuel filler bolt circle spacing.
I shot some photos of the City and as you will see, it really drops toward the back which makes it a good fit for the ST1300 fuel tank. There is an even larger model that was designed for the BMW GS model, but I was told that it really does not fit the ST very well and the City was big enough for my purposes. The City tank bag cost about $275 - but it is extremely well made and in my view, worth the money.
The other good option I found is a tail bag - and I have attached a photo of the inexpensive (but very good IMHO) Moto-Centric tail bag that I got from Motorcycle Superstore for about $75 USD. It is mounted on my 1976 Yamaha XS650C which I am restoring (and really enjoying riding too).
Pete