Introduction
If you’ve ever looked at your car and thought, “I could really use a bit more space up there,” you’re not alone. Roof racks are a popular solution for UK drivers needing to carry everything from camping gear to Christmas trees. But before you fit one, it’s worth asking: how will a roof rack affect your car?
Let’s break it down — the benefits, the drawbacks, and the practical tips that could save you money, time, and a lot of frustration.
What Impact Does a Roof Rack Have on Fuel Efficiency?
Adding a roof rack changes how air flows around your car. That extra frame on top might not seem like much, but at motorway speeds it’s like strapping a small parachute to your roof.
How much fuel does a roof rack actually use?
-
Makes the engine work harder by obstructing smooth airflow, which increases drag.
-
Fuel economy might reduce by 5–15% when a roof rack is empty.
-
Up to a 25% drop can result from a loaded roof box, especially at higher speeds.
-
More noticeable on smaller cars than larger vehicles due to proportionally greater drag.
Real-world driver insights
-
UK motorists report losing 5–8 mpg on long trips with a loaded roof rack.
-
Some drivers find switching to aerodynamic bars reduces this fuel loss.
-
Short, low-speed journeys are less affected than long motorway drives.
-
Removing the rack immediately restores original fuel efficiency.
Do Roof Bars Affect Fuel Economy in the UK?
Yes, and sometimes much more than you may imagine. Even without luggage, roof bars disturb smooth airflow, creating extra drag. Square-section bars tend to be the worst offenders, while modern aerodynamic aluminium bars can reduce the penalty (but won’t eliminate it entirely).
Tips to reduce the fuel hit:
-
-
UK motorists report losing 5–8 mpg on long trips with a loaded roof rack.
-
Some drivers find switching to aerodynamic bars reduces this fuel loss.
-
Short, low-speed journeys are less affected than long motorway drives.
-
Removing the rack immediately restores original fuel efficiency.
-
How Does a Roof Rack Affect Vehicle Handling and Stability?
It’s not just about fuel. A roof rack — especially when loaded — raises your car’s centre of gravity.
Raised centre of gravity and its effects
-
Increases the car’s lean in bends, particularly when driving quickly.
-
Reduces overall stability, particularly in crosswinds.
-
Can make sudden manoeuvres feel less controlled.
-
Requires more cautious driving on country roads.
Braking distance and manoeuvrability
-
Added weight increases stopping distances.
-
Steering may feel heavier and less responsive.
-
Emergency stops require more space to complete safely.
-
More difficult to swerve or change lanes quickly.
What Happens When Carrying a Heavy Load on your Vehicle?
Whether it’s on the roof or inside the boot, a heavy load will:
-
Slow acceleration
-
Increase fuel consumption
-
Wear tyres and suspension faster
-
Make steering feel heavier
UK law is clear — you must not overload your vehicle. Doing so could land you with fines between £100–£300, or worse if it affects your driving.
How Much Extra Wind Noise or Drag Does it Produce?
Why wind noise increases
-
Air rushing around the bars creates turbulence and whistling sounds.
-
The noise gets louder as speed increases.
-
Boxy loads (like suitcases or coolers) amplify the noise.
-
Can be tiring for the driver and passengers on long trips.
Minimising noise and drag
-
Fit aerodynamic bars or wind deflectors.
-
Keep loads streamlined and covered where possible.
-
Check fittings regularly to prevent rattles and vibration.
-
Remove the rack when it’s not in use.
What are the Legal Limits and Risks for UK Drivers?
Overloading rules and penalties
-
Follow the roof load limit stated in your car’s manual.
-
Overhanging loads must be clearly marked and within legal limits.
-
Fines range from £100–£300 for overloading offences.
-
Licence points or court appearances may result from severe situations.
Bike racks vs roof racks legal considerations
| Aspect | Roof Racks | Bike Racks |
|---|---|---|
| Number plate visibility | Rarely blocks the number plate or lights. | Can obscure number plates and lights, requiring an additional plate and lighting board. |
| Legal risk | Low risk if used correctly and within load limits. | Higher risk of fines or penalty points if plates/lights are obscured. |
| Load security | Loads must be secured with straps or clamps. | Bikes must be secured with proper mounts and straps. |
| Potential offences | Poorly secured loads may lead to dangerous driving charges. | Poorly secured bikes may cause dangerous driving offences or loss of load fines. |
Could a Roof Rack Affect Insurance or Increase Maintenance Costs?
Insurance implications
-
Non-disclosure of a permanent rack could cause claim issues.
-
Overloading may void cover if it leads to damage or accidents.
-
Insurers may see roof racks as a modification, so check your policy.
- Always check with your physician for weight restrictions and use.
Maintenance and potential car damage
-
Roof racks can scratch paint if not fitted correctly.
-
Metal feet can cause rust spots over time.
-
Extra weight stresses suspension and brakes.
-
Regular inspections help avoid costly repairs.
What are Practical Tips for Safe, Efficient Roof Rack Use?
Loading smartly
-
Put heavy items inside the car, lighter ones up top.
-
Distribute weight evenly along the rack.
-
Keep loads as low as possible to reduce drag.
-
Use straps or netting to secure everything tightly.
Regular checks and protection
-
Inspect bolts, mounts, and straps before each journey.
-
Clean under mounting points to prevent dirt scratches.
-
Apply protective pads where the rack touches paint.
-
Replace worn straps or damaged fittings immediately.
Mind total vehicle height
-
Measure your new height with the rack and load fitted.
-
Watch for height-restriction signs in car parks.
-
Be aware of low bridges and garage entrances.
-
Lower tall loads before entering enclosed areas.
You’re About to Go Down a Steep Hill — How Should you Control your Speed?
If you’re carrying a roof load, you’ll have extra momentum pushing you downhill. To stay safe:
-
Select a lower gear before starting the descent
-
Use engine braking rather than riding the brakes
-
Apply brakes firmly in short bursts rather than constant light pressure
This reduces the risk of brake fade and keeps your stopping power ready if you need it.
Pros, Cons, and Tips of Using a Roof Rack
Pros
-
Extra storage space without upgrading your car
-
Ideal for bulky or awkward items (bikes, kayaks, camping gear)
-
Keeps the inside of the car more comfortable for passengers
-
Flexible — can be removed when not needed
Cons
-
Increases fuel consumption
-
Adds wind noise
-
Can affect handling and braking
-
Potential for scratches or rust if poorly maintained
-
May impact insurance if misused
Top Tips
- To conserve gasoline, remove the rack when not in use.
-
Choose aerodynamic bars to reduce drag and noise
-
Stick to your car’s weight limits
-
Spread weight evenly and secure loads tightly
-
Clean and check mount points regularly
Conclusion
So, how will a roof rack affect your car? For UK drivers, the answer is clear — it can increase fuel costs, create extra noise, change how your car handles, and even lead to legal or insurance issues if used incorrectly. But when fitted and used sensibly, it’s a great way to gain storage space without buying a bigger vehicle. Just remember: the best way to avoid the downsides is to remove it when it’s not in use.
FAQs
How much does a roof rack increase fuel use?
Usually 5–15%, sometimes more with bulky loads.
Can I get fined for misusing a roof rack?
Yes — overloading or unsafe loads can result in fines and points on your licence.
Will a roof rack void my insurance?
Not automatically, but misuse or non-disclosure could cause problems.
How can I reduce wind noise?
Use aerodynamic bars, add wind deflectors, and remove the rack when not in use.
Is it safe to drive down a steep hill with a loaded roof rack?
Yes, if you use engine braking, control speed early, and avoid overusing the brakes.
