What is the benefit to restricting them?
Hi Andrew:
I noticed the rather considerable movement of the panniers on my ST 1100 back in 2002 when I purchased the moto. I assumed that the freedom of movement was there for a reason (although I could not figure out what that reason was), but at the same time, I was concerned about accelerated wear of the components as a result of the movement. By 'wear', I mean fretting of the hook portion of the pannier and of the rail that the hook sits on.
So, I developed a small modification that would minimize the movement of the panniers during normal operations, but still leave the two panniers free to move (as originally designed) if a force was exerted on them. The modification consisted of two interventions, as follows:
First, I took note of where the round rubber bumper on the pannier rested against the rear mudguard. I then drilled a hole in the mudguard, and fitted a bolt into the hole, choosing the head size of the bolt so that it would be the same size as the inside diameter of the round rubber bumper on the pannier. The result was that when the pannier was installed, the round rubber bumper encircled the bolt head, and this stopped movement along the vertical and fore/aft axes of the motorcycle, while still permitting lateral (inboard-outboard) movement if that was necessary.
A unplanned but significant benefit of this bolt installation is that it made it very unlikely that the pannier would come off the motorcycle if I failed to close up the locking mechanism at the lower front of the pannier. The photos below illustrate this modification:
Bolt Size Selection
Bolt Installed in Mudguard
Pannier Rubber Bumper fitted over the bolt
The second modification was addition of a rubber bungee cord (connected to a 'Bungee Buddy' installed on each pannier) that ran behind the licence plate. This bungee cord minimized inboard/outboard movement of the panniers, but still left them free to move if a force was applied to them. The picture below shows that installation.
Bungee Cord Connecting the Two Panniers
(it runs behind the licence plate - you can see the bungee cord hooks on either side of the licence plate)
Since embodying these two modifications, I have travelled over 100,000 miles on the motorcycle, and there is no evidence of wear at any of the pannier attachment points, or at the rubber bumpers. This particular motorcycle has spent the bulk of its life based in Switzerland, and I often cruise at very high speeds (about 180 km/h) in Germany. I have never noticed the saddlebags flopping around, regardless of speed or wind conditions.
Michael