JimMc
Platinum Member
Several drive ratios are available for the gearboxes and, in addition, the pulleys for the belt drives are also a factor in blade speed. But you are correct in that given the same gearbox ratio and pulley configuration, the longer blade would have a higher tip speed.
Higher tip speed can, and the key word is "can", deliver a cleaner cut, higher lift, a more even discharge pattern, and allow a faster ground speed while mowing on the plus side. On the down side, unless a machine is engineered with high tip speeds in mind, high speeds can lead to vibration, reduced bearing life, belt failures, greater travel of ejected foriegn objects and noise. Ever listen to those commercial mowers as compared to your home lawn mower? Normally you hear the exhaust of a home lawn mower but the blades singing on the commercial unit. In fact, various agencies have different standards for tip speed on commercial vs consumer mowers. Bottom line is you can't just change the drive ratio and reap the rewards of higher tip speed without making some other adjustments. Sort of like hopping up an engine to run 10,000RPM and not doing some bottom end work to hold it.
Higher tip speed can, and the key word is "can", deliver a cleaner cut, higher lift, a more even discharge pattern, and allow a faster ground speed while mowing on the plus side. On the down side, unless a machine is engineered with high tip speeds in mind, high speeds can lead to vibration, reduced bearing life, belt failures, greater travel of ejected foriegn objects and noise. Ever listen to those commercial mowers as compared to your home lawn mower? Normally you hear the exhaust of a home lawn mower but the blades singing on the commercial unit. In fact, various agencies have different standards for tip speed on commercial vs consumer mowers. Bottom line is you can't just change the drive ratio and reap the rewards of higher tip speed without making some other adjustments. Sort of like hopping up an engine to run 10,000RPM and not doing some bottom end work to hold it.