Polaris PRO QD verse LoudHandle's chosen upgrades for reference
An update from my previous post. I'm not using a bearing plate anymore. I'm actually just replacing the tunnel sides with thicker sheet that has my 9 inch center to center built in. Jack shaft stays in the stock location, driveshaft moves down and back, I also raise the tunnel height a little and build a double pass cooler out of a thermodynamically efficient extrusion that only resides under the fuel tank. No more ice ball on top of the tunnel.
Thought I'd post the info I just PM'd SNWMBL
The stock PRO QD drivetrain w/o drivers is; 16.412 #'s (weight is with the 4 Wahl round Aluminum Flangettes with standard bearings and snap rings)
959 Grams; Stock caliper w/ mount, pads, and hose
835 Grams; Stock disk (unlightened, ZRP will lighten it for $75)
896 Grams; 4 Standard bearings in Walh Broz round flangettes with snap rings
1807 Grams; Stock Aluminum large hex driveshaft w/ stock collar and QD fastener (no drivers) no stock Bearing or flangette
1806 Grams; Stock Jack Shaft with Stock Fasteners
1155 Grams Stock QD complete
I don't have any unmodified C3 setups but with my Titanium and Ceramic hybrid bearing upgrade 58T lower and the full range of upper sprockets (in the ratios I chosen to run for my 9 tooth drivers) it comes in at 1234-1295 Grams
I would not run the stock caliper, the Wilwood PS1 is a much better double piston caliper and will mount easier without the Stock heavy steel slide shoe mount, and be far lighter (it will actually bolt right up to the stock Polaris chain case or QD plate w/o any modifications).
So even if you chose to upgrade to an aftermarket belt drive, 1 or two of the better aftermarket driveshaft collars (Happy Face is my recommendation), run the stock shaft or one of my double splined drive shafts. Your still almost 5-6#s lighter, depending on the AVID driver weight penalty.
My current stage of development is 18.5 #'s complete with 9 T 2.86" P involute drivers
5217 Grams; My double spline driveshaft complete with 9T drivers, bearings in Wahl Flangettes, 58 T C3 sprocket, Yeti disk with my aluminum hub, Wilwood PS1 caliper with Ti bolt upgrade, My aluminum caliper mount / Wahl flangette adapter, Happy Face collar with Ti fastener upgrade, TI shaft bolts with heavy BRP steel washers.
845 Grams; TI upgraded C3 drive minus the 58 T sprocket (heaviest ratio)
2350 Jack Shaft w/ loaded Wahl Flangettes and stock steel fasteners and BRP heavy steel washers.
My plans are to get the shaft flat washers water jetted out of some 1/4" 6-4 TI plate I have and go to all TI shaft fasteners.