We built this calculator specifically for people training to lift the Nicol Walking Stones using rings with weight-loadable pins. It calculates the weight for each pin using the weight ratio of the original Nicol Walking Stones. Enter weights in your preferred unit (kg or lb) - the ratio will work the same either way.
The total weight of the Nicol Walking Stones is 252kg (555.5 lb). The large stone is 138kg (304.2 lb), and the smaller stone is 114kg (251.3 lb) - a ratio of about 1:0.826. This calculator rounds to 2 decimal places.
There are a few alternative calculation methods that might be useful to know if you need to figure out the weights to use, but don't have access to this calculator.
Firstly, you can calculate the small weight as 80% of the large weight. For example: 80% of a 120kg large weight would be 96kg.
With a 130kg large weight, the small weight will be 104kg instead of 107kg, only a 3kg difference using the simple 80% method.
Another method is to use 'the 25kg gap' where you simply keep 25kg (or 55lbs) between the large weight and the small weight.
The 25kg gap is easy to remember and calculate. But the downside is that it is less accurate at lower weights. Using the calculator, 145kg would be 79kg and 65kg - a difference of ~14kg. Using the 25kg gap you would use 85kg and 60kg which is a much larger imbalance.