This calculator helps you determine the appropriate spring rate for your K-Tech suspension. Understanding spring rates is crucial for optimal performance, handling, and rider comfort. A spring rate that is too soft can lead to excessive sag and bottoming out, while a spring that is too stiff can result in a harsh ride and reduced traction.
Road Sport
Track Day
Motocross (MX)
Enduro/Off-Road
Adventure Touring
function calculateSpringRate() {
var riderWeight = parseFloat(document.getElementById("riderWeight").value);
var bikeWeight = parseFloat(document.getElementById("bikeWeight").value);
var intendedUse = document.getElementById("intendedUse").value;
var resultDiv = document.getElementById("result");
if (isNaN(riderWeight) || isNaN(bikeWeight) || riderWeight <= 0 || bikeWeight <= 0) {
resultDiv.innerHTML = "Please enter valid positive numbers for rider and bike weight.";
return;
}
var totalWeight = riderWeight + bikeWeight;
var springRate = 0;
// Basic spring rate estimation formula (this is a simplified model and real-world application may require more factors)
// A common starting point is to aim for approximately 10-12% of total weight as the static sag.
// Spring rate is often measured in N/mm or lb/in. We'll output N/mm for this example.
// Adjustments based on intended use (these are general guidelines and can vary)
var useFactor = 1.0;
switch (intendedUse) {
case "road_sport":
useFactor = 1.0; // Standard
break;
case "track_day":
useFactor = 1.1; // Slightly stiffer for more aggressive riding
break;
case "motocross_mx":
useFactor = 1.3; // Significantly stiffer for jumps and rough terrain
break;
case "enduro_offroad":
useFactor = 1.2; // Stiffer than road, but with some compliance
break;
case "adventure_touring":
useFactor = 0.9; // Softer for comfort and load carrying
break;
default:
useFactor = 1.0;
}
// A very rough approximation of spring rate in N/mm
// (Total Weight in kg * 9.81 m/s^2) / Desired Sag Percentage
// Let's aim for ~30-35mm static sag on a typical suspension travel of ~120-150mm for general use.
// This translates to roughly 20-25% sag. We'll use 22% for this example.
var desiredSagMm = 0.22 * 120; // Assuming 120mm of travel as a reference for calculation basis
springRate = (totalWeight * 9.81) / desiredSagMm * useFactor;
// Convert to kgf/mm for common motorcycle suspension units
var springRateKgfmm = springRate / 9.81;
resultDiv.innerHTML = "
Estimated Spring Rate:
";
resultDiv.innerHTML += "Based on your inputs, a recommended spring rate is approximately: " + springRateKgfmm.toFixed(1) + " kgf/mm";
resultDiv.innerHTML += "Disclaimer: This is a general estimation. For precise tuning, consult your K-Tech suspension dealer or a professional suspension tuner. Factors like rider skill, track conditions, and specific suspension components can influence the ideal spring rate.";
}
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