Calculation of spring strength for expedition vehicles

Bee

2 months ago

Spring calculator for expedition vehicles

From "The Cold Storage Trick" – Burkhard Menn

Important notes on the calculation:

Objective: Pre-dimensioning, non-standard verification
Vehicle: ladder frame, expedition truck
Bearing: Fixed bearing at the rear, spring-loaded at the front
Accelerations: 0.5 g (realistic, not normative)
Safety factor: 1.8 (flat rate)
Frame torsion angle: 4° (conservative empirical value)

📏 Not sure how to determine the values?
Here you will find a detailed Instructions for determining measured values on the vehicle with pictures and step-by-step explanations.

⚙️ For technicians and engineers:
Want to understand how the calculation works? Here is the complete derivation with formulas and interactive visualization:
→ The physics behind the spring calculation

Choose your spring assembly:

Case A: One spring or several springs next to each other (transverse)

Case B: Several springs in a row (direction of travel)

Cabin weight (kg)

Distance fixed bearing to front spring (m)

Distance from center of gravity to fixed bearing (m)

Height center of gravity above spring level (m)

Track width (m)

⚠️ IMPORTANT: This is the distance between the left and right spring on the main frame, NOT the wheel track width! Typically 0.8-1.0 m for truck ladder frames. Values that are too large lead to dangerously weak springs!

Number of springs per side (side by side = 1)

Number of springs per side (one behind the other)