How roof boxes and bike racks could invalidate your car insurance
Tue, 03 Jun 2025
Motorists planning a summer road trip are being warned that common modifications such as fitting roof boxes and bicycle racks could invalidate their car insurance.
Tow bars and window tints could also end up costing motorists, warns Quotezone.co.uk.
All such changes must be declared to an insurer, or car insurance policies are at risk of being voided. If a motorist needs to make a claim, an insurer could refuse to pay out.
Many common summer additions such as roof boxes and bike racks can be classified as modifications. Cycle carriers, for example, are seen as increasing the likelihood of damage or an accident, particularly if not installed correctly.
Indeed, all such additions "can be seen as increasing the risk of an accident or the likelihood of damage, which is why it’s so important to notify the insurer," says car insurance expert Greg Wilson.
"There’s a full list of modifications that insurers need to be aware of. It’s important for drivers to check the list thoroughly as some items are quite unusual and many drivers may assume they are covered as standard."
Failing to inform the insurer of these changes could invalidate the insurance and leave the driver unprotected.
Roof boxes are a common summer modification, but Wilson says that, as they are not standard equipment, they can impact a vehicle’s weight distribution and, potentially its handling. Poorly-secured or overloaded roof racks can also be dangerous.
Window tints can be a controversial area, but they do not automatically invalidate your car insurance – provided they’re legal and the insurer has been informed.
Rules state that at least 75% of light must pass through the windscreen and at least 70% through the front side windows. There are no restrictions on tinting the rear windows. Premiums are unlikely to go up with this modification.
As for tow bars, towing another item increases the risk of an accident happening. Car insurers must be informed before fitting – and check your policy covers the item you’re towing, too.
Are modifications recorded on the motor insurance database?
