As promised I took some measurements and calculated the blade tip speed. I took RPM readings on the engine and then the right side deck pulley with the blades running. I used my laser tach to take the readings.
1. The rear pulley under the engine is 6" OD, at least to my eye. The deck pulley is 5.75" OD thus the deck pulleys turn slighter faster than the engine RPM
2. With G5s on the engine RPM was 3490 and the deck pulley was 3810
3. With stock blade (601124) the engine RPM was 3499 and the deck pulley was 3809
Thus there is little difference in blade tip speed between the two blades.
The blade tip speed is 18453 fpm. Thus the blade tip speed is 447 fpm on the slow side. In other terms, a little less than 2.5% off of the target value.:thumbdown:
For what it is worth the unit cuts pretty dang good as is. Now I have to decide if I want to adjust myself, take it to the dealer or leave it alone.