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A study has revealed that a whopping 52% of drivers are unaware that they must declare all car modifications to their insurer. And, even more surprisingly, the same study revealed that 45-54-year-old retirees are the most likely age group to modify their vehicles, instead of the often stereotyped ‘boy racers’. We know that the older men get, the more important it is to have a nice car to them. But remember: understanding how car modifications affect insurance can’t be overlooked whatever your age. 

From car modifications for aesthetics to those for improving the safety and handling of your vehicle, all types of modifications will have some sort of impact on your premiums – and most importantly all have to be declared to your insurance provider. 

Whether you have an annual policy, use temporary car insurance, or are learning to drive with temporary learner insurance – if modifications haven’t been declared, you run the risk of your policy being invalidated…

Car Modifications That Affect Insurance

Car modifications can do a number of things to your car, change the aesthetics, improve handling, increase safety, increase speed, and so much more. If you are making changes that don’t impact how the car drives, or changes that should increase safety and vehicle control, you might be thinking ‘why would I need to declare that’ or ‘that won’t make a difference to my insurance’. But if you look at it from an insurer’s perspective, any change you make to your vehicle could be increasing your vehicle’s value or making it more prone to theft or damage – all things that your insurer will care about. 

The below modifications legally need to be declared to your insurer and will have an impact on your premiums.

List of Modifications That Must Be Declared:

  • Engine Modifications
  • Mechanical Modifications (exhaust, brakes, transmission etc)
  • Wheel Modifications (not including winter wheels)
  • Bodywork Modifications –
  • Wing & Spoiler Changes
  • Wheel Arch Changes
  • Side Skirt Additions
  • Exterior Light Changes
  • Window Tinting
  • Suspension Modifications
  • Brake Modifications
  • Paint Jobs, Stickers & Decals
  • Interior Modifications –
  • Seat Changes
  • Light Changes
  • Pedal Changes
  • Steering Wheel Changes

Car Modifications That May Raise Your Premiums

Before you set out to get your car modified, consider the increased cost to your insurance premiums that might ensue. If you are making your car more valuable, more likely to be stolen, or making it faster and potentially accident-prone there’s a good chance your insurance costs will go up.

But whatever you do, don’t avoid declaring these to try and avoid insurance cost increases – doing so can cause your insurance to be invalidated, meaning you will be illegally driving without valid insurance. Something that isn’t worth the risk…

Paintwork Changes, Stickers & Decals

Maintaining the paintwork on your vehicle is important, as the paint layer acts as a protective layer for your bodywork. However, if you decide to have your car custom-painted for a hefty price, this could also have a knock-on effect, as this raises the value of your car – making it more attractive to thieves. 

Additionally, insurers will associate certain paints or decals with drivers who are more likely to make claims, meaning you might just be painting yourself with the wrong brush in opting for a new paint job.

Engine Modifications & Upgrades

Installing a turbo on your vehicle’s engine might improve the performance and fuel efficiency of your car, but it can also raise your insurance. This is because a turbo engine is usually more expensive to fix, while adding power and speed can also increase the risk of an accident in the wrong hands. 

In addition, failing to declare the addition of a turbo to your vehicle could void your insurance entirely. Alternatively, engine tunes and remaps could also invalidate your policy if you fail to mention them to an insurer.

Cold Air Intake Changes

If you install a Cold Air Intake to improve engine combustion you must declare it, it may only slightly increase your premiums.

Wheel Modifications

If you are switching from steel wheels to alloy wheels you are likely to see an insurance premium increase. This is because whilst they may make your car easier to drive, they are also more expensive and are very alluring to thieves. 

Trying to make your wheels a bit more swish? Unfortunately, even the simple act of painting your standard wheels could raise your premium, with upgrading them likely to be even more costly. 

Some wheel modifications are illegal in the UK, including stretched tyres and mixing tyre types. 

Car Light Modifications

Many modifications of car lights will not impact your insurance premiums, but some modifications can cause issues. 

The first of these are LED strips on the bottom of your car. When these are mixed with a history of claims, theft, and irresponsible driving, your insurer is likely to increase your premium. 

In addition, coloured LED headlights and flashing under-car lights are illegal and therefore invalidate your insurance.

Adding Nitrous Oxide Systems

While these systems are not illegal themselves (as many believe), they can increase your premium by as much as 132% – meaning they are exceptionally costly additions to your vehicle. 

However, if you fail to tell your insurer about these mods, these could be considered illegal. In addition, these systems can be dangerous when improperly installed, as they increase cylinder pressure.

Lowering Car Suspension

Car suspension can be lowered as long as this doesn’t detrimentally affect the steering of the car or the angle of the headlights. However, any suspension adjustments must still be declared as lowering your car can make it more prone to damage whilst driving over speed bumps, or uneven road surfaces.

Modifying the Exhaust System

Any modifications to your exhaust system are likely to increase your premiums due to increasing engine performance. 

It is also important to note that any modifications that remove exhaust silencers creating a loud exhaust system are illegal in the UK.

Upgrading Brake Discs

While upgrading your brake discs will improve the safety and control of your car, opting for more costly discs like carbon ceramics or slotted brake discs will increase your vehicle’s overall value. Which you guessed it, leads to an increase in insurance premiums.

Bodywork Modifications

Bodywork modifications may be to personalise your car’s style, but they can have detrimental effects on safety and thus will increase your premiums. For example, adding larger bumpers or side skirts to your car will increase the risk of damage on bumpy roads and from squeezing through tight gaps.

Other body modifications that will also impact your premiums include – modified wheel arches, flared wings, and the addition of spoilers and valances.

Gear & Transmission Modifications

Changes to your gearbox will alter how your car drives, they must be declared to your insurer as they may make your car more of a risk on the road. Any gearbox modifications are very likely to cause your insurance premiums to rise.

Seat Modifications

Changes to the seats within your car can impact your insurance in several ways. If you reupholster them or upgrade them you are making your car more valuable meaning your premiums will rise. If you replace your seats with alternatives that don’t add value but also don’t comply with safety standards then premiums are likely to rise too. 

Whatever changes to your seats are made, they must always be declared.

Car Modifications That May Lower Your Premiums

Some modifications will lower your premiums, in some cases, this is only the case if your car is already modified. They all still must be declared to your insurer…

Engine Downsizing 

Opting for a smaller, lighter engine will increase your car’s energy efficiency and make it safer to drive. Doing this will decrease your premiums

Adding High-Performance Brakes

Uprated brakes will make your car safer to drive, whilst these won’t always reduce your premiums, especially if they add increased value – if your car is already highly modified. However, the addition of these could decrease your premiums.

Upgrades to Suspension

If your car is already highly modified and you upgrade your suspension to improve drivability, your premiums could be decreased.

Adding a Sway Bar

Adding a sway bar to your car will increase your safety and may decrease your insurance premiums. Sway bars can stabilise your car while taking tight turns and prevent rolling.

Adding a Water Cooling System

If your car is already modified, adding in a water cooling system to improve the performance of your brakes can contribute to lowered premiums. 

Adding a Tow Bar

As a tow bar will mean you will have to drive slower, this can also reduce your premiums.

Illegal Car Modifications That Will Invalidate Your Insurance

Even if you declare these modifications, you could invalidate your insurance due to legalities. If you have any of these modifications, your car cannot be legally driven in the UK:

  • Tinted windows that block more than 70% light
  • Certain light modifications, including:
  • Flashing lights
  • Additional red lights
  • Green lights
  • Visible bulbs
  • Visible LED strips
  • Interior LED lights
  • Modifications that increase the noise of your car – like removing the exhaust silencer
  • Some wheel modifications – including stretched tyres.
  • Some mechanical modifications, including:
  • Removing the catalytic converter
  • ECU remapping
  • Injecting nitrous oxide into the combustion chamber

So if any of the above are on your car modification wishlist, strike them off if you want to be able actually to drive your vehicle.

Hopefully, you are now a lot more clued up on modifications and their impact on your insurance. Always remember to notify your insurer of any modifications made otherwise you risk invalidating your insurance altogether. Remember to weigh up the impact of any modifications on your insurance before you commit…

And if you would rather borrow someone’s already green car before painting your own, our temporary car insurance is here for you.

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