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I've alluded to concerns with the mechanical design of the tail subassembly on Zeros. Unfortunately, what fueled my concerns reached a small crisis today, so I'll try to lay out an argument and what to do about this situation. My priorities: (1) fix this for me, (2) document it on the wiki manual, (3) hopefully prevent others from the same mistakes or vulnerabilities, (4) raise the attention of someone at Zero so the 2018 models are better. I can't expect to influence 2017 models at this point.

My DSR's current demands on the tail design are (in order of loading demands): (1) the tail rack, (2) the Corbin seat, and (3) the OEM side racks. It's possible that the problem I'm experiencing requires all of these interacting at once but I can't say.

My Corbin seat will not settle into its intended position the way the bracket is mounted; the bracket is at least positioned 1/4" aft of where it would align properly, which means the seat must be structurally compressed to thread the seat bolts. This means that my seat bolts have been experiencing some shear for about six weeks, and with all the troubleshooting and teardown I've been doing, threading and unthreading the seat has been a bit of a time bomb that I haven't made time to fix because I've been focused elsewhere.


I will figure out how to communicate this problem to Corbin but I don't expect my current seat to be fixed (moving the holes that little will just weaken the pan), and as of today, the holes for the seat bolts are now nearly fully stripped(!), which I need to address ASAP after little more than a month of usage.

There's this thread to reference for a fix: Quick removable seat. I've avoided that design out of structural integrity concerns, but am considering something like it now.

Also: wiki manual entry for the tail removal

Now, I need to lay out why this whole scenario is even possible, and how no larger motorcycle manufacturer has this problem: the seat is mounted to the frame with load bearing bolts. There is no justification for this other than "they haven't gotten around to designing something better".

What is the seat loaded with? Everything listed above, into the tail assembly itself which is separate from the frame. I'd say if Zero intends to reach a broader market where third parties support accessories more widely, the frame or tail assembly needs to integrate the top plate or at least the grab bars that it mounts to. Any loading on the top case has both a static and dynamic effect on all the bolts involved, and seat bolts that must be operated more than twice per year should not be part of that structural equation.

Some have carried extra charging capacity in a top case, most notably Terry, but it's worth noting that Terry's tail rack has extra bracing running from the lower center part of the frame out to the plate itself (part of a custom-welded side rack concept that I'm trying to emulate shortly).

I'm motivated with some urgency because my situation is complicated: I'll be commuting 80 miles per day instead of 20 miles per day starting tomorrow, my 2013 DS has been unavailable for months because of insurance issues after a car knocked it over in January (it was intended for supercharger testing and fabrication testbed, so that fell through), and I still need to test the supercharger further, helping test software tweaks mainly. This year has been a bit of a drag in many ways...

With all that said, can someone recommend suggestions that won't impact the structural life of the vehicle? Let's assume I can get a reasonably priced tail assembly replacement soon and swapped, and that I will make some quick compromise for now for safety until this is sorted.