You can produce a smaller pulley on the rotor shaft, then you will have bigger ratio.
Hello Mister Yuan,
Reducing the flail mower rotor pulley shaft diameter to increase the speed ratio is a double edged sword so to speak for a number of reasons.
The blade tip speed will be increased and thusly increase the chance of impacting the forward knifes edge and damaging depending on the knife station hanger separation distance as relates strictly to the individual flail mower rotor diameter i.e. 2 row, 3 row or the 4 row knife station flail mower rotor.
The scoop knife/duckfoot-hate that/Cast Hammer flail knife would also be affected by this due to the increased tip speed in some cases affecting the knife cutting efficiency where it would simply bounce off the material.
2. plugging and wrapping of the flail mower rotor with heavy brush.
3. reduced bearing life on the drive pulley open flange bearing (B10 life).
a. reduced bearing life on driven pulley open flange bearing(B10 life).
b. reduced bearing life on the flail mower rotor bearings(B10 life).
4. increased belt wear/reduced V belt life.
There are other reasons but the above reasons are more than adequate to explain why one should not attempt to change the pulleys to change the speed ratio on the flail mower rotor.
The use of a larger flail mower rotor diameter pulley would allow the end user to make use of shorter side slicer lengths with tool less blade installation and removal and as a result save a lot of money on knife replacement if needed.
The added benefit of the above would allow the flail mower rotor to match the speed of the driven pulleys diameter to obtain the same high quality of cut.
The smaller flail mower rotor diameter using a steel tube is a compromise with the blade tip speed with the use of the longer knife being used to equal the combined radius of the larger pulley diameter and the shorter knife length.
Me I like not needing tools to change knives to sharpen them or install the thatching knives on my towed flail mower.