Car modifications: Will they affect your Car Insurance?

If you're a fan of the franchise, the quickest way to get Furious, Fast is to modify your car and not tell your insurer. A voided policy, a rejected claim, and a repair bill that's entirely yours to cover: that's a bind even Vin Diesel couldn't drive out of.

A wise person once said “the only thing you must do to a car is buy it”. There are engineers and designers in Japan, Italy, Germany, Korea, France and China who know what they're doing. Yet, South Africa has a thriving car modification culture. From lowered Golfs in Jozi, mobile boom boxes and kitted out and lifted bakkies in the Karoo, South Africans love standing out by “uniqueifying” their rides. Most of those modifications are perfectly legal. Some are not. And almost all of them have implications for your Car Insurance that your insurer expects you to know about.

Here is what you need to understand before you visit the fitment centre.

What counts as a modification?

For insurance purposes, a modification is any change to your vehicle that departs from the manufacturer's original factory specification. That covers everything from a new sound system and custom paint to a turbo upgrade or a suspension lift.

From a legal standpoint, vehicle modifications in South Africa are governed by the National Road Traffic Act (NRTA) 93 of 1996. The Act sets out what is permissible in terms of roadworthiness and safety. Modifications that compromise either of those can render your vehicle unroadworthy, expose you to fines or impoundment, and, critically, make your Car Insurance claim invalid.

The Automobile Association (AA) is clear on this: before modifying your vehicle, check that the changes are legal, safe, and compliant with the NRTA. Many insurers will not cover vehicles with unauthorised modifications.

The golden rule, just disclose everything

When you take out Car Insurance, your insurer prices your policy based on the vehicle's risk profile as it left the factory. Change the vehicle, and you change the risk. It is your legal and contractual obligation to tell your insurer.

This obligation cuts both ways. If you modify your car before taking out a policy, declare it upfront. If you modify it after your policy is in place, notify your insurer as soon as the work is done.

If you buy a used car that has already been modified, the same rule applies. Declare every modification the previous owner made, whether or not you plan on keeping them.

How common modifications affect your Car Insurance

The table below gives an overview of how common modifications may be viewed by insurers. NB: Individual policies vary, so always confirm with your specific insurer.

A closer look at high-impact modifications

Engine and performance upgrades

Turbochargers, engine swaps, nitrous oxide kits, and exhaust modifications all signal one thing to an insurer: more power. More power means a higher assumed accident risk, which typically means a higher premium. TopAuto reported in November 2024 that significant engine changes may require re-certification to confirm roadworthiness and emissions compliance under the NRTA.

Suspension changes

Lowering or lifting your suspension is popular, but both carry risk if done incorrectly. Under South African law, the maximum allowable suspension lift is 50mm from the manufacturer's original specification without requiring a Letter of Authority (LoA) from the National Regulator for Compulsory Specifications (NRCS). Exceed that, and you need NRCS approval before the vehicle can legally be used on a public road. Without it, your insurer is under no obligation to pay a claim.

Tinted windows

Window tinting is legal in South Africa, but within strict limits. The NRTA requires a minimum of 35% visible light transmission (VLT) on side and rear windows, and 70% VLT on windscreens. Limo tint, which falls well below the legal threshold, is illegal. Insurers regard below-legal tint as both a safety hazard and a policy breach. If your windows do not comply, expect your claim to be complicated.

Anti-theft devices: the modification that works in your favour

Not every modification pushes your premium up. Vehicle Tracking systems, electronic immobilisers, gear locks, and hood locks all reduce your theft risk, which is something insurers reward. If you compare Car Insurance quotes through Hippo, you will find that some providers offer specific discounts for approved Vehicle Tracking devices -which can also be found on hippo.co.za. It is the one modification worth talking to your insurer about before you buy.

Bigger wheels

Fitting larger diameter wheels and wider tyres changes the effective rolling circumference of the wheel. That matters because your car's gear ratios are calibrated to the factory tyre size. Go bigger, and the ratios shift: the engine effectively has to work differently through each gear, your speedometer can under-read your actual speed, and braking distances may increase. Insurers view incorrectly fitted or oversized tyres as a handling and safety risk, and if a claim arises where tyre specification is a contributing factor, an undeclared change in wheel size gives them grounds to dispute the payout.

What happens if you don't disclose?

Non-disclosure of material information is one of the most common grounds for claim rejection in South Africa. If your insurer discovers an undeclared modification during a claim assessment, they have grounds to:

• Reject your claim outright

• Declare your policy void

• Refund your premiums and leave you uninsured

If your insurer discovers an undeclared modification during a claim assessment, they have grounds to reject your claim, declare your policy void, and refund your premiums — leaving you fully exposed. The Ombudsman for Short-Term Insurance (OSTI) confirms that non-disclosure of material information is one of the most consistently upheld grounds for claim rejection in South Africa. A claims assessor will inspect your vehicle after any incident. They know what factory specification looks like. If something has changed and was not declared, they will find it.

Compare Car Insurance quotes on Hippo

Whether your car is completely standard or thoughtfully modified, the most important step is making sure your cover reflects reality. Hippo lets you compare Car Insurance quotes from a range of FSP-registered insurers side by side, so you can find a policy that works for your vehicle and your budget.

Enter your details once. Compare in minutes. Your better starts here.

This article is for informational purposes only and does not constitute financial, legal, medical or insurance advice. Hippo is a comparison site helping you evaluate quotes from trusted South African insurers. Always review policy details before making changes. Quotes are risk profile dependent and subject to annual review. No fees are charged for using Hippo’s comparison service. HAS (Pty) Ltd and HCS (Pty) Ltd are authorised FSPs. Terms and conditions apply.