April 22nd, 2025.



Customising your road-legal quad can enhance its performance, security, or appearance, but it is essential to understand the insurance implications of any changes you make.

While some legal modifications are generally accepted, others could increase your premium or even lead to a loss of cover if not declared. Jessica Lofts, BikeMatters expert at Lexham Insurance, explains how five common modifications could affect your coverage:

1. Road-legal aftermarket exhausts and end cans: Dependent on the changes made
Providing that they comply with Euro regulations, aftermarket exhausts and end cans are performance modifications that will generally be accepted by insurance companies. However, any increase in performance can also increase the value of your bike, which furthers the risk so it is important to declare these changes to your provider. If your exhaust takes your bike outside of its class (ie.125cc) and you do not have the correct insurance, your policy can be invalidated.

2. Engine changes: Can result in coverage refusal
Swapping out a engine is often easier than doing so in a car, but it can unintentionally create significant insurance complications. Insurers classify vehicles based on a designated rating system, typically determined by the power of the vehicle. Installing a larger cc engine can render this classification invalid, often resulting in immediate removal from cover.

Engine modifications can also introduce handling challenges, increasing the risk of accidents and making you a higher liability to insurers, many of which may ultimately refuse to provide coverage altogether.

3. Aftermarket alarms and immobilisers: May actually save you money
These are arguably some of the best adjustments you can make to your bike, and on some occasions may be able to save you money on your insurance policy. Recognised examples of security include those that are Thatcham-approved, however, this will vary between insurers so it is worth confirming before committing to anything.

4. Grips and heated grips: Usually okay, but could impact claims if undeclared
More of an accessory than a modification, grip changes are usually cosmetic and often done to switch colour or to add a heated option for winter. While this is a change that typically won’t affect your insurance, nondisclosure of modifications and/or accessories could impact future claims, so it is essential to consider their implications. This might not mean a rejection, but it could slow down the process because of missing important information.

5. Replacement or rebuilding of a frame modification: Typically a no-go for insurers
This modification can have both performance and cosmetic benefits; however, it is the performance impact that raises alarms with your insurance provider. Much like an engine swap, this type of modification poses a higher risk to insurers, and if you have replaced or rebuilt your frame, you are more than likely to be refused a standard policy.

The impact of modifications on your quad insurance will depend on your provider and the specifics of your policy. In general, modified bikes are more expensive to insure due to their increased value or enhanced performance which are both key factors in determining insurance premiums. This increases the risk for insurers and the potential cost of claims which is why they can affect the insurance policy premium or insurer acceptance.

To avoid the risk of your policy being voided in the event of a claim or accident, it is essential to declare any modifications to your insurer.

For more information on quad modifications and how they can affect your insurance policy, visit: www.lexhaminsurance.co.uk/blog/what-modifications-void-motorcycle-insurance/

For Lexham quad insurance CLICK HERE.