Finnz, I am not sure of the actual RPM's as a friend of mine was taking the readings but I am quite sure tge Menz 20x10s loads the motor quite well. If you are planning to use a Mejlik I think you will have to go with a 21x10 or even a 22x10 on this motor as they seem to turn up a good deal more. I run a Mejlik 20 x 10 on my BME 44 and in turns in the mid to high 7000's. I went with the Menz on this plane in an effort to reduce weight. I am not sure on the Zingers, Bolly's, etc. Hope this helps, cbk