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The History Behind The Calculator
The History Behind The Calculator
Born from a 200 Series Build
Born from a 200 Series Build
This calculator wasn’t built by a software company - it was built in a garage.
It started when I was setting up my own Toyota LandCruiser 200 Series for touring. Like many 4WD owners, I had a long wish list: bullbar, winch, drawers, roof rack, dual batteries, and a fridge. But as I started adding up the numbers, I hit a wall.
I realized that despite the LandCruiser's reputation as the ultimate tourer, the factory payload is surprisingly low once you start modifying it. I built a complex spreadsheet to track every kilogram, calculating moment arms and axle loads to figure out where I sat legally.
The Reality of Modern 4WDs
The Reality of Modern 4WDs
There is a misconception that 4WDs are built ready to cross the continent straight off the showroom floor. The reality is that manufacturers design these vehicles for stock standard conditions. They are not engineered by the factory to carry 400kg of steel protection, recovery gear, and camping equipment while towing a caravan.
Most 4WDs will hit their Rear Axle Limit long before they hit their total GVM limit. This creates a dangerous "cantilever effect" where weight in the back lifts the front wheels, reducing steering traction and braking efficiency.
The "Engineer's Frustration"
The "Engineer's Frustration"
As an engineer, I found it baffling that a tool like this didn't already exist.
We spend tens of thousands of dollars modifying our vehicles, yet figuring out if we are actually legal involves guessing, complex maths, or a trip to a weighbridge when it’s often too late. It became clear that staying legal isn't just about being careful - it’s actually mathematically difficult given how these vehicles are designed.
I realized that if I was struggling to balance the numbers with an engineering background, most other 4WDers were likely driving unknowingly overloaded vehicles. I decided to turn my personal spreadsheet into a public resource.
More Than Just Compliance
More Than Just Compliance
I was stocked when I took my vehicle over a weigh bridge with only bullbar and winch and nobody on board that it was over its front axle rating. While avoiding fines and insurance denials is critical, this project isn't just about ticking a regulatory box. It’s about building better vehicles.
A vehicle that is within its weight limits - and properly balanced across its axles - is a superior vehicle.
Stability: It handles predictable in emergency manoeuvres.
Comfort: The suspension works as intended rather than sitting on the bump stops.
Capability: You maintain traction and clearance when off-road.
This tool is designed to help you plan your build before you spend the money, ensuring your rig is safe, legal, and ready for the tracks.
Keeping it Free
Keeping it Free
You might notice ads or product links on the site. My goal is to keep this calculator 100% free for the 4WD community - no subscriptions and no paywalls. I am not looking to make a fortune from this project; however, hosting a web application and maintaining the database does incur costs. The advertising you see simply helps cover these server expenses, ensuring the tool stays online, fast, and free for everyone to use when planning their next build.
Contact Us
Contact Us
Get in Touch / Report a Bug
Get in Touch / Report a Bug
"Found a bug in the calculator?"
"Have a GVM upgrade kit specs you want added?"
"Interested in advertising?"
This calculator is a community project. While I try to keep the database current, there are always new models and aftermarket accessories hitting the market.
If you spot a bug, have a suggestion, or want to submit specs for a vehicle not currently listed, please use the form below. Your contributions help keep this tool free and accurate for everyone.
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