The old RAM mount system I used on my previous motorcycle didn't fit my Aprilia RSV1000R, so I designed a 51mm fork mount for my Aprilia on which the Garmin gps holder is bolted.I think the stl with less support is for a 53mm Fork, the 45 stl is for an 51 fork with the closing end at 45 degrees. But I'm not sure anymore! So download the scad and modify to your needs.I changed the clamp opening to 45 degrees because it touched my brake fluid reservoir, also added some extra support.[3-9-2011] Had my first testrun yesterday and nearly lost my GPS... the bracket broke, which I mainly blame on a jammed extruder during printing, causing some weak layers in the bracket. Before it broke I noticed lots of vibrations so I think it may be wise anyway to add some more structure to get a sturdier bracket. I now came up with v3, which I will be testing next.9790.2845 mm of filament used in this printthe print goes from 23.79 mm to 150.22 mm in X and is 126.43 mm widethe print goes from 52.3 mm to 149.66 mm in Y and is 97.36 mm widethe print goes from 0.35 mm to 49.35 mm in Z and is 49.0 mmUpdate: I've used the v3 for some time now and it holds very good, strong enough for this type of use I would say. The position isn't perfect, you have to look down to have look at the GPS.Adjust the OpenScad file to your fork diameter (I used 52mm for a 51mm fork and 54mm for a 53mm fork). Export to stl and print.Break or cut off the supports.Fix the clamp with a 4mm bolt and nut.