How fast do you have to run to make a reel mower work?

Q: My neighbor says that reel mowers don’t work. He says he can’t get the reel to spin fast enough to cut his grass, even if he runs. How fast do you have to run to make a reel mower work?
A: You do not have to run, or even to walk fast to get your reel mower to cut the grass. You will get the same great scissors cut when walking at any speed.
“Push” or “manual” reel mowers are “ground driven”. That means that, unlike power mowers which are engine driven, the cutting mechanism on a push reel mower – the reel – turns when the wheels turn against the ground. The wheels cause the reel to turn because there are pinion gears inside the wheels. There are teeth on the pinion gears and teeth on the inside of the wheels. The teeth mesh together so that when the mower is pushed and the wheels turn, the pinion gears also turn. The pinion gears are attached to the reel shaft, so when the pinion gears turn, the reel spins at the same rate.
How fast the reel spins depends on the “gear ratio” or the number of teeth on the gear relative to the number of teeth on the inside of the wheels. Mascot Silent Cut reel mowers, for example, have 14 teeth on the pinion gears and 63 teeth inside the wheels. The result of this is a 4.5 ratio: the reel spins four and a half times for each turn of the wheels. It does not matter how fast the mower is pushed. Every time the wheels turn one time, the reel will spin 4.5 times. The gear ratio is about the same on each of the several reel mowers that I have checked.
The Mascot “10 inch wheels” are actually about 10.25 inches in diameter, which means they are a little over 32 inches in circumference. So at each rotation of the wheels, the mower will cover about 32 inches of ground. The reel is spinning 4.5 times for each turn of the wheels, and there are six blades on the reel. So we multiply the gear ratio by the number of blades and learn that the reel blades will make 27 passes at the cutter bar, making 27 cuts for every 32 inches of travel. A five bladed reel mower with the same gear ratio and the same sized wheels would make 22.5 cuts for every 32 inches mowed.
Your pushing speed is not important, but the number of blades on the reel is important. Choose a mower that is designed to cut your turf grass and push it at your own speed. How the number of blades affects the cut is another blog. For now, just remember that you do not have to be a track star to get a great cut from reel mower.