sourbeer
I did this install a couple of weeks ago, had to modify it to strengthen it up and just got around to snapping a few pics. http://imageevent.com/saubier/motorcycles/st1300
The box works great, is certainly water tight and seems to handle my intended needs very well. I wanted a low profile box to house my laptop case for commuting which is what i do with my bike most. I didn't care if it came on/off as I knew I would leave it on. I wanted it to be lockable and secure as well as a good box to transport important things in. The side cases didn't fit my laptop bag very well. So, I first took off the plastic cover from the rear rack and used it as a template to mark the holes to be drilled in the bottom of the box. Went to the hardware store and got 4 button head bolts with nylon lock washer nuts and some washers - everything stainless. I installed the case using just those four points and used it for a couple of days like this. I wasn't happy with the amount of flex that the box had so I decided to reinforce the box with a piece of sheet metal on the inside. I cut a piece of aluminum sheet metal and rounded the corners so that it would fit inside the box nicely. To secure the sheet metal to the box i used the 4 little round feet that the bottom of the box had. These feet were in the middle of the ridges that run across the bottom of the box providing some strength to the box. I used some big washers and more stainless hardware to secure the box to the sheetmetal. Turned out very well and provided all of the strength that i hoped for without adding too much additional weight. The box is very secure now. Not sure if it adds to any high speed wobbly problems but have tested it to 110 mph (GPS indicated) without a hint of unstable behavior.
The box works great, is certainly water tight and seems to handle my intended needs very well. I wanted a low profile box to house my laptop case for commuting which is what i do with my bike most. I didn't care if it came on/off as I knew I would leave it on. I wanted it to be lockable and secure as well as a good box to transport important things in. The side cases didn't fit my laptop bag very well. So, I first took off the plastic cover from the rear rack and used it as a template to mark the holes to be drilled in the bottom of the box. Went to the hardware store and got 4 button head bolts with nylon lock washer nuts and some washers - everything stainless. I installed the case using just those four points and used it for a couple of days like this. I wasn't happy with the amount of flex that the box had so I decided to reinforce the box with a piece of sheet metal on the inside. I cut a piece of aluminum sheet metal and rounded the corners so that it would fit inside the box nicely. To secure the sheet metal to the box i used the 4 little round feet that the bottom of the box had. These feet were in the middle of the ridges that run across the bottom of the box providing some strength to the box. I used some big washers and more stainless hardware to secure the box to the sheetmetal. Turned out very well and provided all of the strength that i hoped for without adding too much additional weight. The box is very secure now. Not sure if it adds to any high speed wobbly problems but have tested it to 110 mph (GPS indicated) without a hint of unstable behavior.