K-Tech Spring Rate Calculator
Optimize your motorcycle suspension performance
Understanding K-Tech Spring Rates
Choosing the correct spring rate is the fundamental first step in motorcycle suspension tuning. K-Tech Suspension components are world-renowned for their precision, but even the best valving cannot compensate for an incorrect spring rate. The spring's job is to hold the motorcycle and rider at the correct height (SAG) while allowing the suspension to move through its stroke effectively.
Why Spring Rate Matters
If your spring is too soft, the suspension will sit too low in its travel, leading to harshness as it hits the stiffer part of the progressive damping curve or bottoms out. If the spring is too stiff, the bike will feel "toppy," lack mechanical grip, and fail to transfer weight correctly during braking or acceleration.
Calculation Methodology
Our K-Tech Spring Rate Calculator uses industry-standard linear approximations for K-Tech performance springs. It factors in:
- Rider Weight: This is the total mass including helmet, leathers, boots, and gloves (typically +10kg/22lbs over body weight).
- Application: Racing requires higher rates to handle the extreme forces of high-speed braking and cornering compared to street riding.
- Bike Geometry: Heavier bikes require higher base rates to manage the static mass of the machine.
Typical Recommended Ranges
| Rider Weight (Gear On) | Front Rate (N/mm) | Rear Rate (N/mm) |
|---|---|---|
| 65kg – 75kg | 8.5 – 9.0 | 85 – 90 |
| 75kg – 85kg | 9.0 – 9.5 | 90 – 95 |
| 85kg – 95kg | 9.5 – 10.0 | 95 – 105 |
| 95kg+ | 10.5+ | 110+ |
Fine-Tuning with K-Tech
Once you have installed the recommended K-Tech springs, it is essential to measure your "Static Sag" and "Rider Sag." For most sportbikes, a rider sag of 30mm-35mm for the front and 25mm-30mm for the rear is the target for track use, while street riders may prefer slightly more (35mm-40mm) for comfort.