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What vehicle modifications might void car insurance?



If you’re planning to modify your car in some way you might already be aware of the fact that some modifications can increase the cost of your car insurance, but what happens if you make the modifications after you’ve taken out your policy?
Here’s a quick overview of the types of modifications that could invalidate your insurance if you fail to disclose them to your insurance provider.

Arranging modified car insurance before heading out on the road is an absolute necessity for any driver, of course. But just as important as getting a suitable car insurance policy is making sure your coverage is adequate for your personal circumstances, including the type of vehicle you are driving.

If you have made changes to your car and failed to declare them to your insurer, there is a risk this could invalidate your cover. Consequently, it’s vital to be aware of the impact of modifications on car insurance and to always be upfront with your provider.

Modifications that might invalidate your car insurance

The modifications most likely to have an impact on car insurance premiums, and potentially invalidate your cover if they are not declared, are those that are perceived to either increase the risk of the driver being involved in an accident or increase the risk of the vehicle being targeted by thieves.

Undeclared modifications designed to enhance the performance or appearance of the car are the most likely to render a policy invalid. These include:

  • Turbo/supercharging
  • Bodywork changes
  • Transmission or gear change
  • Exhaust modifications
  • Air filters
  • Body kits or panels
  • Specialist paintwork
  • Uprated brakes

Any of these modifications, or other adjustments intended to improve the look or performance of your vehicle, must be added to your insurance policy in order to maintain your cover, even though there’s a good chance your car insurance premium will rise once you disclose the modifications.


You stand a far better chance of finding a cheaper quote if you compare policies from a wide range of providers

It’s also worth considering policies that are specifically designed for certain vehicle types, such as high-performance car insurance and 4×4 insurance.

Car modifications that sometimes don’t affect insurance

It’s always a good idea to keep your car insurance provider up to date with any changes to your vehicle, but some modifications will only have a negligible impact on your policy and premiums, or no effect at all.

In some cases relatively minor and commonplace adjustments such as tinted windows and alloy wheels might be seen as low-risk, but even so they should still be declared.

It’s also important to remember that some modifications can affect your insurance in a positive way – lowering your premiums by cutting the risk of accidents. Parking sensors, for example, reduce the likelihood of minor collisions and prangs, while installing an alarm of engine immobiliser will reduce the risk of vehicle theft.

How will declaring modifications impact my premiums?

Certain modifications will increase the cost of your car insurance, for the simple reason that providers will assume a higher-performance car has a higher risk of being involved in an accident, while a car that looks more attractive to thieves has a higher risk of being stolen.

Research has suggested that the adjustments likely to result in the biggest increases in premiums are:

  • Turbocharged engines
  • Modifications to bodywork
  • Transmission or gear change
  • A complete body kit and panels
  • Roll bars, roll cages and seat removal

While some drivers might be reluctant to declare these modifications and see their insurance costs go up, if you fail to do so you could find yourself without cover if your car is stolen, and possibly in legal trouble if you have an accident on the road.

Modified car insurance for young drivers

Younger drivers who want to make changes to their cars could face some particularly steep insurance premiums, as the insurer will combine the perceived risk of the modifications with the fact that younger motorists are statistically more likely to be involved in an accident.

One of the options available to these drivers is to look for the best modified car insurance that reflects the changes made to their vehicle. Comparing dedicated insurance for young drivers is another option that can help to reduce costs.


You stand a far better chance of finding a cheaper quote if you compare policies from a wide range of providers

Furthermore, younger drivers can take steps to lower their premiums by showing they are responsible motorists, such as choosing a car with a smaller engine or completing the Pass Plus course. Third-party car insurance can sometimes be a cheaper option than fully comprehensive cover too, although that isn’t a hard and fast rule.

The risks of not declaring modifications on car insurance

Quite simply, the risk of failing to declare vehicle modifications to your insurance provider is that your policy will be invalidated.

If your car is stolen or involved in an accident, the insurer could decide that the modifications were a key factor in the event, and if these features were not declared, you could find that you aren’t covered. Suffice it to say, this raises the risk of some very serious financial and legal consequences.

Illegal car modifications

As well as being aware of vehicle adaptations that could invalidate the insurance and affect premiums, drivers need to know about modifications that are governed by strict legal constraints.

Tinted windows, for example, must let in at least 75 per cent of light through the front windscreen and 70 per cent of light through the front side windows.

There are also legal constraints on car modifications like neon lights on cars. Vehicles should not be fitted with lamps that show a red light to the front or anything other than a red light to the rear. Green lights are not permitted at all, as these should only be used on medical practitioners’ vehicles.

Other UK laws govern car modifications like stretched tyres and large exhausts. If you are planning on modifying your car, make sure you are fully aware of the legal restrictions and declare all changes to your insurer so you’re fully covered.

This article is intended as generic information only and is not intended to apply to anybody’s specific circumstances, demands or needs. The views expressed are not intended to provide any financial service or to give any recommendation or advice. Products and services are only mentioned for illustrative rather than promotional purposes.

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