Bodom Posted June 24, 2019 Share Posted June 24, 2019 (edited) *UPDATE: I was not happy with some numbers and I calculated the whole process again... now it should be correct* This one is for the number guys and nerdy freaks: Until now the calculation for the IronMind-Number from a rated gripper has been made with this formula: ((Meassured weight - standard weight) / difference) + standard number = rating But this formula got one problem: depending on the standard gripper you got heavy variations. As a simple example shall be any gripper with a rated weight of 65kg / 143,298lbs. We can insert this weight into the formula and we use as reference a CoC #2, CoC#3 and a CoC #4: CoC #2: ((143,298 - 110) / 27) + 2 = 3,23 CoC #3: ((143,298 - 150) / 40) + 3 = 2,83 CoC #4: ((143,298 - 209) / 59) + 4 = 2,88 All 3 values are not correct. Why? A little picture will show: This are the "correct" values for the Captains of Crush-Grippers. Beginning with a #2.5 and ending with a #3.0 - devided by 0.01. Now we can see: the 143,298lbs (65kg) is a 2.84 - not a 3.23 or any of the other calculated values. Even for the IronMind-Standard-Grippers the formula can not offer correct results. We use a #4 as standard: Captains of Crush #1: ((83 - 209) / 59) + 4 = 1,86 Captains of Crush #1: ((110 - 209) / 59) + 4 = 2,32 Captains of Crush #1: ((150 - 209) / 59) + 4 = 3,00 Captains of Crush #1: ((209 - 209) / 59) + 4 = 4,00 But why can't we get any correct results? The formula just provides approximated values based on a standard gripper. That means that the meassured gripper just behaves like a 3.23, 2.83 or 2.88 compared to a standard gripper. Now how can we get around this problem? The solution is quite simple: we use the actual values from the intermediate stages. Those are not provided by IronMind but we can calculate them quite simple. For this we use another picture: You can seet that the CoC #1.5, #2.5 and #3.5 placed just in between the standard grippers #1, #2, #3 and #4. A standard #1 is rated at 83lbs, a #2 at 110. The average is exactly the strength of a #1.5: 96.5. We can use this for every other intermediate stage. The course of the Captain of Crush just differs at the #1, #2, #3 and #4. You can see that in the picture above. Now I calculated the ratings for every intermediate stage - graded by 0.01 (if we use more decimal places it's just getting more difficult, annoying and the athlete does not feel the difference by closing the gripper): Spreadsheet: RGC Rating vs. IronMind Numbers Now comes the fun part: How did I calculate the values for the #5 and #6? Well for this I take the standard values of the current #1, #2, #3 and #4 and create coordinates: A(83|1), B(110|2), C(150|3) and D(209|4). Now follows a simple math function for creating the graph: f(x) = ax³ + bx² + cx + d We can now insert our 4 points and create 4 formulas: 83 = a1³ + b1² + c1 + d = a + b + c + d 110 = a2³ + b2² + c2 + d = 8a + 4b + 2c + d 150 = a3³ + b3² + c3 + d = 27a + 9b + 3c + d 209 = a4³ + b3² + c4 + d = 64a + 16b + 4c + d Now we have to find the correct values for a, b, c and d. For creating a standard formula we have to convert those variables into constants. Step 1: formula 5 = formula 2 - formula 1: 27 = 7a + 3b + c formula 6 = formula 3 - formula 2: 40 = 19a + 5b + c formula 7 = formula 4 - formula 3: 59 = 37a + 7b + c Step 2: formula 8 = formula 6 - formula 5: 13 = 12a + 2b formula 9 = formula 7 - formula 6: 19 = 18a + 2b Step 3: formula 10 = formula 9 - formula 7: 6 = 6a This is now the first constant we can calculate: a = 1. We can roll up the hole process from behind to get our values by inserting a = 1 into formula 8: 13 = 12 * 1 + 2b => 13 = 12 + 2b => 2b = 1 => b = 0,5 a and b are inserted into formula 5: 27 = 7 * 1 + 3 * 0,5 + c => 27 = 7 + 1,5 + c => c = 18,5 And finally we calculate d by inserting a, b and c into formula 1: 83 = 1 + 0,5 + 18,5 + d => d = 83 - 1 - 0,5 - 18,5 => d = 63 We have to check if we made any errors: 83 = 1 + 0,5 + 18,5 + 63 110 = 8*1 + 4*0,5 + 2*18,5 + 63 150 = 27*1 + 9*0,5 + 3*18,5 + 63 209 = 64*1 + 16*0,5 + 4*18,5 + 63 Every equation is correct and we got the formula we were looking for: f(x) = 1x³ + 0,5x² + 18,5x + 63 With this we can calculate the values for a theoretically #5 and #6 by setting x = 5 and x = 6: f(x) = 1*5³ + 0,5*5² + 18,5*5 + 63 = 293 f(x) = 1*6³ + 0,5*6² + 18,5*6 + 63 = 408 The chart for Ironmind standard grippers is shown in the following picture: Please be adviced that this only is correct for the CoC #1, CoC #2, CoC #3, CoC #4, CoC #5, CoC #6 etc. The intermediate stages have to be calculated by the values in the first part. Edited June 25, 2019 by Bodom 3 Quote Link to comment Share on other sites More sharing options...
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