RH1300S wrote:Do the discs actually 'pump' air?
Could you rig up something so that you could attach a flexible duct to the inside of the disc (just have the free end somewhere you can feel/measure any flow) - I'm sure you could make up a box in cardboard to seal off the driveshaft etc as you would have to if you made the thing properly. Have the car wheels off the ground and run it in gear to a decent roadspeed? If it's pumping anything surely you could measure/feel the flow into the duct.
Great idea! To see what happens with the car off the ground and in gear would give me some feel. I can use whool strings and some tape...
What I do know is that the brake disc dealer tells me: the discs do pump air in the brake testing bench.
I think that with the rim arround they act as a kind of centrifugal air fan but maybe it would be better with an internal rim cover that doesnt have relative speed 0 with the disc like the rim does.