Journeyman
"And this one is just right" ~ Goldilocks
Most excellent- thank you!Hi Journeyman
What Mr Pix means is that there are a number of fixing options (4 times 8mm) into the rear frame that can be used for a pannier bracket . Triumph use 2 for their panniers and 2 for their backrest and rear rack. H and B use 2 for theirs but they use the backrest holes not the ones Triumph use for the pannier brackets. This means that holes in the under guard (the plastic cover that effectively acts as a rear mudguard (fender) would be exposed and let the crap get in. However when you buy the pannier kit you get an extra under guard pre-drilled for the bracket fixings. You can then use the original one for the H and B bracket fixings. If you haven't got the Triumph pannier kit then your under guard will not have any holes in it anyway. You are going to have to drill it for the H and B fixings.
The strength issue comes from the fact that with both the Triumph pannier brackets and the H and B brackets you are relying on all the weight in each pannier being supported on two 8mm bolts which fix upwards into the rear frame (by far the weakest type of fixing for load bearing). I believe that this is why both Triumph and H and B only rate their panniers at a paltry 5 kg load. Incidentally the huge Corbin bags only use 3 of the 8mm fixings and they do not specify a load for their bags (I know this because I asked them twice and they didn't reply!) I don't know how heavy the Corbin bags are but they must pretty heavy to start with.
I have H and B bags and fixing but I have added an extra support for the brackets using one of the free 8mm holes. It was quite a job to make the extra brackets, but I'm now confident that my bags will take a bit more weight without issue.
You asked about the Orbit bags, I have not seen those (I have the C-Bow Buffalo bags), What I can say is that the quality from H and B is excellent so I would imagine those would be fine (if a little small). I don't like the look of the C-Bow brackets and they get very scratched quite quickly taking the bags on and off. I like to have the bags on the bike all the time so it doesn't bother me.
Hope that helps
Steve