R1200GS aux tank mounted on AltRider pillion rack

Marc11

Premier Member
#2
I have a the same mounting setup on my 2017 GS and passed tech for this year's ibr. If you read the ibr rules the tank has to firmly attached to the bike, it should not move independent of the bike with the exception of tanks mounted to the stock bike pillion mounting points.

When using the pillion mounting points some tank/mounting plate movement is allowed as that is how the pillion seat/plate were designed by the bike mfg.

So in short, so long as the tank is firmly attached to the plate with zero movement, and the plate is frimly attached to the bike using the same attachment points as the OEM seat you should be fine.
 

EricV

Premier Member
IBR Finisher
#3
Who did your tech this year Marc?

Typically fuel cells mounted to seat mounts do not pass tech. Several have been specifically failed for this in the past years. It is NOT recommended because they have a tendency to launch during a get-off. I've personally seen this occur. Getting smacked in the back of the helmet with a 4.25 gal fuel cell partially full of fuel is not recommended. The seat latch is simply not designed to handle that much weight and the inertia of a sudden impact during a crash can be violent.

If you want to stick with the mount set up you have, add an additional securing feature. Looking at the '16 GSA in the garage, an additional bracket across the cell from the pannier rack mounting points or even the grab bar bolt would likely be sufficient. In the past Tech has had riders put a ratchet strap across the fuel cell as an expedient measure for the IBR, but that is not preferred.

FWIW, I've worked for Warchild doing Tech inspections multiple years. Marc's set up slipped past us this year. I'm not sure why.
 

Marc11

Premier Member
#4
Yeah mine slipped by, there were at least three of us that "slipped" by. I'm not opening this crap can of worms by saying who did my tech or who else was called over to confirm my venting and inspected my tank.

And there is no way my tank is flying off the bike in a get off unless it is a catastrophic hit from behind, the rear of the GS has a three point mounting system, very robust, may not have been designed for the 40 pounds of fuel but when mounted to a plate that is spreading that load across all three points IMHO it isn't going anywhere.
 
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EricV

Premier Member
IBR Finisher
#5
Marc, I was A. There in Greenville doing tech. B. have a GSA in the garage. Dale always has the final say. I'll certainly go read the '19 rules. I wasn't given them since I wasn't a rider in '19. They should be online for public view now. I certainly could be wrong. I know I wouldn't pass a cell mounted to pillion seat mounting points only. I've see fuel cells depart bikes in a crash. And I stand by my point that the latch and mounting for the seat is not designed for the kind of weight a fuel cell presents.

Just read the '19 rules and I see no provision for pillion seat mounted tanks. I see the following applicable sections:

3. Any auxiliary tank(s) shall be mounted in a secure manner so as to minimize the chance of its becoming separated from the motorcycle.17 Approval of attachment systems rests at the discretion of the rallymaster or the president.

17. When pressure is applied to the fuel cell, limited visible movement (i.e., 1/2") relative to the frame of the motorcycles will be permitted only if it is due to the compression of padding on which the tank ispositioned. However, all tanks must be secured to the motorcycle with straps or fasteners that are securely connected to a bracket or structural member that does not flex when pressure is applied to the auxiliary tank. No bungee, shock cord, or similar attaching device will be permitted.
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If you see something I'm missing, please bring it to my attention.

It's completely moot if StormRider just wants this for his normal use and is not planning on rally use. If he plans on rally use, it will fall to the individual rallymaster to allow it or not. For the IBR, I don't recommend it for the reasons I noted.