Originally Posted by nononsense4857
Wracked my brains for ways to get the surface profile right...
Found these and tried to source it from friends for a day... so that they can be scanned for the surface profile
Any better idea?
that "650R" insert can be used to fabricate a pair of exact copies in steel. these would become your baseplates. the drilled dowels that you already have would be carefully cut to fit the required depth and angle to fit the existing M8 mounts behind the plastic tail fairings. as you tighten the M8 fasteners, the baseplates will be pulled into general conformance with the desired shape. the shape can be fine tuned with a hammer and sandbag backing, easy.
once the shape and try fit are satisfactory, bolt the base plates in place with the dowels still loose behind them.
fabricate pannier mounting points out of something like 4mm x 30mm flat that will run with the length of baseplate, terminating 10mm from the ends. radius the outside corners 10mm, and pre drill properly spaced holes for 3 M8 fasteners. this mounting point will be welded perpendicular to the baseplate above the baseplate mounting holes, and needs to be scribed and ground to perfectly fit any contour in the baseplate. i recommend that this mounting point run parallel to the upper edge of the baseplate.
once fitted, the mounting points should to tack welded in place with the baseplates mounted on the bike. protect adjacent surfaces. this locks the contour. unbolt the baseplates and tack the dowels in place. try fit the assemblies, and if everything still checks, finish the welding.
now you're ready to mount the hoops using mounting points that correspond to the baseplate to make it easy to demount the pannier racks. the trick here is to make sure that the pannier hoops are parallel to each other in two planes. takes some clamps and straight edges, plus more tack welding in place. it's the only way to do it accurately in a one off fabrication, but the process is easy.
weld a tab on the back of the hoop to accept a cross brace. the brace should be located where it is inconspicuous, but will not get hit by the rear tire at full suspension travel.
at least there's no snow on the ground...