OK... RB Racing's sprung clutches are fictional from what I have gathered from other riders. Too bad, they seemed like a nice idea! Then I started to Google 180mm clutches and kept on coming up with early 60s Volkswagen Beetle stuff... so... $48 including postage later I have a new 180mm sprung clutch disc from a Volkswagen Beetle. Worn out R1100 GS on left, new VW Beetle on right Both are 180mm wide. Both fit on the same on the GS's input shaft. The only difference is that the VW clutch is thicker, 9mm vs 5mm remaining on my BMW disc - I have no new BMW clutch to use as a reference - what are they supposed to measure? The only difference is the thickness of the center hub. BMW = 20mm and the VW is 25mm - The BMW could easily be machined down by 5mm and be identical. I have yet to assemble to see if the springs get in the way of anything... but there are unsprung versions of this clutch as well. So... the only other "real" aftermarket 180mm clutch is the Touratech four puck disc at $650 and change! Which got me to thinking about getting some ceramic four puck clutches made up... there are a few places that make custom VW clutches around... Questions I have for the group would be: - How thick is the stock R1100 GS clutch? - How thick is the Touratech four puck ceramic clutch? I am sure I could get ceramic clutches built for a LOT less money than Touratech!!