Understanding Weight Limits
Exceeding your car’s roof weight limit is dangerous and illegal. This guide helps you calculate exactly what you can safely carry.
Three Critical Numbers
- Dynamic Roof Load: Maximum weight your car’s roof can carry while driving (check manual)
- Box Weight: Empty roof box weight (15-25kg typically)
- Roof Bar Weight: Weight of roof bar system (8-12kg)
Formula: Maximum cargo weight = Dynamic roof load – Box weight – Bar weight
Common Car Weight Limits
- Small cars (Fiesta, Polo): 50-60kg total
- Medium cars (Golf, Focus): 65-75kg total
- Large cars/SUVs (X5, Qashqai): 75-100kg total
Example Calculation
VW Golf owner with 420L Thule box:
- Dynamic roof load: 75kg
- Thule Motion XT weight: 18kg
- Roof bars: 10kg
- Maximum cargo: 47kg
What Weighs How Much?
Typical item weights:
- Sleeping bag: 1-2kg
- Pillow: 0.5-1kg
- Clothing (week’s worth per person): 5-7kg
- 2-person tent: 3-5kg
- Pair of skis + boots: 5-8kg
- Medium suitcase (packed): 15-20kg
Smart Packing Strategy
- Heavy items: Keep in car boot (suitcases, books, tools)
- Bulky but light: Perfect for roof box (sleeping bags, pillows, clothing)
- Medium weight: Pack over roof bars for best support
- Fragile items: Never in roof box
Warning Signs of Overloading
- Roof sagging or bowing
- Unusual creaking noises from roof
- Difficulty steering or unstable handling
- Clamps loosening frequently
If you notice any of these, stop immediately and reduce weight.
Unsure about your car’s weight limit? Bring your vehicle handbook to our Birmingham location and we’ll help you calculate safe loading capacity for your specific setup.