How To Build A Racing Mower
|
|
Pulley Ratios Results In MPH This is a basic guide to pulley selection. Transmission types, 3 speed to 6 speed transaxles will vary these ratios. The size of your rear tires will also have an impact on the speed.
Trans Pulley3" ENGINE PULLEY
3 inch 3.5 inch 4 inch 4.5 inch 5 inch 5.5 inch 6 inch 6.5 inch 3.5" ENGINE PULLEY 3 inch 3.5 inch 4 inch 4.5 inch 5 inch 5.5 inch 6 inch 6.5 inch 4" ENGINE PULLEY 3 inch 3.5 inch 4 inch 4.5 inch 5 inch 5.5 inch 6 inch 6.5 inch 4.5" ENGINE PULLEY 3 inch 3.5 inch 4 inch 4.5 inch 5 inch 5.5 inch 6 inch 6.5 inch 5" ENGINE PULLEY 3 inch 3.5 inch 4 inch 4.5 inch 5 inch 5.5 inch 6 inch 6.5 inch 5.5" ENGINE PULLEY 3 inch 3.5 inch 4 inch 4.5 inch 5 inch 5.5 inch 6 inch 6.5 inch 6" ENGINE PULLEY 3 inch 3.5 inch 4 inch 4.5 inch 5 inch 5.5 inch 6 inch 6.5 inch 6.5" ENGINE PULLEY 3 inch 3.5 inch 4 inch 4.5 inch 5 inch 5.5 inch 6 inch 6.5 inch 7" ENGINE PULLEY 3 inch 3.5 inch 4 inch 4.5 inch 5 inch 5.5 inch 6 inch 6.5 inch |
Pulley Ratio 3" ENGINE PULLEY
1.000 0.857 0.750 0.667 0.600 0.545 0.500 0.462 3.5" ENGINE PULLEY 1.167 1.000 0.875 0.778 0.700 0.636 0.583 0.538 4" ENGINE PULLEY 1.333 1.143 1.000 0.888 0.800 0.727 0.667 0.615 4.5" ENGINE PULLEY 1.500 1.286 1.125 1.000 0.900 0.818 0.750 0.692 5" ENGINE PULLEY 1.667 1.429 1.250 1.111 1.000 0.909 0.833 0.769 5.5" ENGINE PULLEY 1.833 1.571 1.375 1.222 1.100 1.000 0.917 0.846 6" ENGINE PULLEY 2.000 1.714 1.500 1.333 1.200 1.090 1.000 0.923 6.5" ENGINE PULLEY 2.167 1.857 1.625 1.444 1.300 1.182 1.083 1.000 7" ENGINE PULLEY 2.333 2.000 1.750 1.556 1.400 1.273 1.167 1.077 |
MPH 3" ENGINE PULLEY
21.50 18.43 16.13 14.34 12.90 11.72 10.75 9.93 3.5" ENGINE PULLEY 25.09 21.50 18.81 16.73 15.05 13.67 12.53 11.57 4" ENGINE PULLEY 28.66 24.57 21.50 19.09 17.20 15.63 14.34 13.22 4.5" ENGINE PULLEY 32.25 27.65 24.19 21.50 19.35 17.59 16.13 14.88 5" ENGINE PULLEY 35.84 30.72 26.88 23.89 21.50 19.54 17.91 16.53 5.5" ENGINE PULLEY 39.41 33.78 29.56 26.27 23.65 21.50 19.72 18.19 6" ENGINE PULLEY 43.00 36.85 32.25 28.66 25.80 23.44 21.50 19.85 6.5" ENGINE PULLEY 46.59 40.31 34.94 31.05 27.95 25.41 23.28 21.50 7" ENGINE PULLEY 50.16 43.00 37.63 33.45 30.10 27.37 25.09 23.15 |
Jack Shaft Set Up
You need a Murray Deck spindle housing Murray part number 55962, a 5/8” dia.3/16 keyway shaft, two 5/8” shaft locks, 3/8” thick plate of aluminum or ¼” thick plate of steel, and a way to cut holes and a notch in your frame.
When locating your jackshaft setup try to get, as close to the middle (front to back) of the frame as possible,this will let your belts be close to the same size. If you get it to close to the rear axle and your belt is too short you will have problems with belt wear and rollover. A chain has been used with some success but you have to tighten the tension sprocket extremely tight. You will use a belt tension idler pulley like the clutch for ease of changing belts. Cut a hole just big enough for the Murray spindle housing to fit flush with the bottom of the frame. Mark and drill holes to mount your housing, after drilling your frame place your plate on top and mark holes to be drilled and drill holes in plate.
After drilling the plate mount your housing and plate together (housing on the top of the frame and plate on top of the frame. You can build a belt tensioner out of 1 ½” by ¼” flat steel or use an old clutch assembly. If you use flat steel cut 2 pieces about 6” long or according to what space you are going to have. Bend a joggle in each piece about ½” high as in you can do this in a vice with a torch and a hammer or if you know someone with a press brake that can bend it that’s even better. After bending drill a hole the size of the pin or bolt the tensioner will turn on thru both pieces. Drill a hole in one piece to fit your pulley or sprocket if you are using chain. Drill a hole in the other to fit your J-bolt. Put a bolt thru the 2 pieces and make sure both ends a bent up as in make them at a right angle. And weld them together. Add your pulley, mount it to the frame put your J-bolt in the other end and see where you can weld your piece of angle so it doesn’t get in the way of the belt. Pull the pulley up tight against the belt hand tight the nut on the J-bolt then tighten it with a socket or wrench until the belt is as tight as possible and will still turn easy. It is possible to get it to tight. This works on chain too.
Steering Linkage
Linkage Angles
