This one's here for Old Time's sake. We don't pull for ratio anymore but we did for years.
Understanding the Pull Ratio
Here is how the ratio is stated in the rules.
Ratio* = (full pull weight/tractor weight)+(pull length/72")*(added weight/tractor weight)
What follows is taken from my score at the Portland Fair last fall.
My tractor weighed in at 3370 and the sled weight was 6500 on the previous pull.
I started pulling at a sled weight 7750.
I pulled the load 72" on my first pull.
The weight added to the sled before my first attempt was 1250.
Here is the calculation for the first pull:
Ratio = (6500/3370) + [(72/72) * (1250/3370)]
Ratio = (1.928) + [(1) * (.370)]
Ratio = 1.928 + .370
Ratio = 2.298
My final pull was at a sled weight of 11,500 which I moved 17 inches. Here is the calculation:
Ratio = (10250/3370) + [(17/72) * (1250/3370)
Ratio = (3.04) + [(.236) * (.370)]
Ratio = 3.04 + .087
Ratio = 3.127
If you check my score from the Portland Fair you’ll see that the ratios are actually 2.300 and 3.129 respectively. That is because the computer uses more places to the right of the decimal in it’s calculation than I did here.
* It is helpful to note that "full pull weight" refers to the sled weight the last time you hooked up where you had to pull the full distance to be able to come back out. If this is your first hitch, that weight is still used.