Most drivers would expect “boy racer” car modifications to increase their insurance premiums. But even those motorists that roll their eyes at the thought of adding tinted windows and loud exhausts to their car could still fall foul of insurers’ rules around changes made to cars.
Even the most genteel car additions such as roof racks and satnavs can bump up insurance costs. This is because changing a car in any way might increase its value, how it handles or how likely it is to be stolen.
For example, adding alloy wheels or leather seats might raise the vehicle’s worth. Insurers are left out of pocket when paying claims for cars modified after buying cover, as it would have been insured at one value and replaced at a higher one.
Aside from increasing the car’s value, additions such as alloy wheels will bump up premiums because they are easily, and often, stolen. If drivers live in an area where this theft is common, their cover costs may increase.
Some modifications, such as bigger engines, new wheels and spoilers, can affect how cars handle. If insurers think these changes will increase the chance of accidents, premiums will rise.
Adding alloy wheels can increase insurance for a Vauxhall Corsa from £927 a year to £974. Likewise, adding a roof rack to a Volvo V70 estate can increase the cost of car insurance from £983 to £1,019.
To save money it is tempting not to mention these modifications to insurers, but doing do might mean the firms reject claims for cars modified without their knowledge.
However, modifications can lower insurance premiums too. For example, fitting a tracking device, better brakes or a more fuel efficient engine will result in cheaper cover costs.
A spokesman for the Association of British Insurers, a trade body, said: "Car insurers are not interested in trying to catch out customers – more than 98pc of all claims made on motor insurance are paid.
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"However if you’re making changes to your car that mean it is different to when you started your cover, it is a good idea to tell your insurer in case it could affect your premium. Some modifications, such as a new security system, could save you money.”
Have you been surprised by modifications changing your premium? Email sam.barker@Finance.co.uk to share your experience.