Spring Rate Calculator

Why Choosing the Right Spring Rate Matters?

Selecting the incorrect spring rate leads to harsh ride quality, poor suspension travel, saggy suspension, and premature wear, especially when your 4WD is carrying gear it wasn't originally set up for. Whether it's a steel bullbar and winch, rear canopy and drawers, or a full touring setup, choosing springs based on your actual, measured load is the key to long-term reliability and comfort.

Measuring Real World Load!

What really matters is the load your 4WD carries every day, not what you might install later. To get it right, we recommend using a weighbridge or corner weight scales and recording your axle loads with the vehicle fully set up as you drive it.
That means: full tank of fuel, bar work, tools, fridge, spare tyres, roof gear, and any other permanent accessories already installed. And don't forget about the passengers!
Avoid choosing springs based on gear you plan to fit later. Lets face it, life happens and those plans can change.
Choosing a spring rate for weight you don't yet have can lead to a poor ride, handling issues, or uneven tyre wear.
Instead, we recommend setting the vehicle up with all your gear fitted first, then upgrading your suspension to suit the actual load.

Stick to Constant Load

Your springs are designed to support the stuff that lives on your 4WD full time. Permanent accessories, like bar work, roof platforms, drawers, fridges, canopy setups and long-range tanks. That's your constant load.
Camping gear, water jerries, luggage and food, not so much. This is where a lot of builds go wrong, people count the occasional gear and end up with springs that ride like a brick when the back's empty.

Let's Get It Right, Together

This doesn't need to be hard, and you don't have to do it alone. At Superior Engineering, we've been setting up suspension for real-world 4WDs for over 20 years, and we know what works.
Using the calculators below, select the gear you have already fitted to you vehicle. This will give you an estimated spring rate to suit your vehicle. Taking the guess work out of it, meaning no more incorrect spring rates.

Alternatively give us a call with your axle weights, list of gear, or even a photo of your setup, and the team at Superior Engineering will help find the best option for your setup.