short answer : stock springs are dual stage 0.32-0.50 kg/mm, after cutting 10 coils (from the side with less spaced coils) stock springs became 0.38-0.50kg/mm. these numbers come from math formula and *are verified by my test at the scale* . imho they are very accurate (error could be +/- 0.01kg/mm) stock springs are: 64 total coils, 30mm outside diameter, 4.3mm wire diameter long answer: i used a scale with continuous refresh, a nut , a washer, a theaded 20mm rod. then i measured the necessary weight to compress (by hand) the spring for a given distance , reading the scale when the rod was touching the scale. easy and fast, i tested 25-50-75-100-125 mm of compression. the statement "short spaced coils compress first" it's completely false. in any point of the spring the distance between coils changes in the same way untill short spaced coils bind. at that point only large spaced coils remain active, causing an increased K (less coils =harder spring). change between "soft" and "hard" spring rate happens when compression is equal to (distance between short spaced coils) x (number of active coils). in a stock springs it happens at about 2.5mm x 62 active coils = 155mm of compression i wasn't able to compress the spring to that point but i verified that compressing my shortened spring (52 actice coils , 0.38-0.50kg/mm, change of spring rate predicted at 2.5mmx52=130mm) coils were almost binding during the 125mm compression test. if you put the spring infos into an online calculator like this: http://www.planetspring.com/pages/compression-spring-calculator-coil-calculator.php?id=compression you will see that you cannot shorten the stock spring too much , in fact the recommended max travel is lower than the total space between coils (20-25% lower). i do not know the math behind the 25% reduction of travel for safety reasons. probably the limit is there to allow a high number of cycles at 75%. going up to 80-85% reduces life of springs for sure so it should not be considered a final mod but rather a try before buying new springs with proper K.