If you want to spiff up your car with aftermarket accessories, be careful. Some aren't good for your car.

The urge to personalize your car with aftermarket accessories is as natural as the urge to set up your living space with furnishings you like. Some people like to jazz up the car’s exterior with new rims or bumper stickers, others like to boost engine performance with air intakes, and others like to illuminate the interior with LED lighting. Personally, I like to keep seat belt extenders plugged in to avoid the annoying warning beep when I drive 20 mph along the country lane on which I live. (Any cops reading this, please note: I always fasten the belts when I get onto a busy street).

Many accessories are benign, but not all. Some, such as steering wheel covers that slip and seat covers that interfere with airbag deployment, create safety issues. Beyond that, some accessories can actually damage your vehicle. In consultation with automotive marketing expert Joe Giranda, this article highlights eight of those.

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Close-up view of a gold alloy car wheel with a low-profile tire, showing the rim details and valve stem, parked on a stone-paved surface with grass patches.
Igor Shoshin/Getty Images

Aftermarket Rims and Low-Profile Tires

Low-profile tires give a car a sporty appearance while improving performance by gripping the road better than standard tires and enhancing cornering and braking. But they can actually be bad for your car, according to Giranda.

“Lower-profile tires can increase the impact and stress on suspension components like bushings and ball joints, and make the ride much harsher. This is especially true if the wheel diameter or wheel offset is different from the manufacturer’s specifications.”

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Air filter with turbocharger in racing car engine
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Cold Air Intakes

The goal of installing a cold air intake is to provide the engine with additional outside air to improve performance. It can draw air from above the hood or from another location that isn’t as hot as the engine compartment. Whether it actually improves performance is debatable, and because it alters the fuel-air ratio, it can just as easily hurt it.

A poorly filtered cold-air intake can damage the engine by introducing contaminants from outside. And there’s a chance of the disturbance in the fuel-air ratio triggering the check engine light, which no one wants to see.

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new car exhaust pipes
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Performance Mufflers

An aftermarket performance muffler is designed to increase airflow from the engine’s exhaust port, theoretically increasing engine output. It makes the engine run louder, but a louder engine isn’t necessarily more powerful.

The downside to aftermarket mufflers is that they’re often made with cheap fiberglass that eventually melts, breaks free and clogs the exhaust opening. In the end, rather then enhancing engine performance, the muffler can seriously reduce it and may shorten the engine’s life. If your aftermarket muffler fails and damages the engine, don’t expect your vehicle warranty to cover the repair.

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shock Absorber and Coil Spring of Car Suspension System
kynny/Getty Images

Lift Kits

When you install a lift kit to raise the height of your vehicle, the thrill of standing above all the rest can exact a toll on performance. Lift kits put extra strain on the vehicle’s linkages, suspension and driveshaft, and they make the engine work harder, costing you more in gas and potentially reducing engine life.

Moreover, by raising the vehicle’s center of gravity, a lift kit presents safety issues. It reduces stability and increases the possibility of rollover, especially if you also install oversized tires. It can also affect your vehicle warranty, says Giranda. “If a problem arises, manufacturers are normally required by warranty law to demonstrate that a modification caused the failure before denying a claim.”

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The process of installing PPF film on the headlight of the car. Selective, blurred focus. Wrapping car.
Dmitry Presnyakov/Getty Images

Car Bras

The purpose of a car bra is to protect the front of your car as it battles its way through slush, mud and hordes of flying insects. Leave it on too long, though, and it will do the opposite. Fitment Industries has a YouTube video that shows how badly a car bra can damage a car’s finish.

The problem is that the bra flaps in the wind and catches dirt, which gets trapped behind it and scratches the paint. Not only that, but the bra prevents the paint on the front of the car from fading along with the paint on the rest of the car. If you don’t want to end up with a two-tone finish with scratches, skip the car bra.

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Bull Bar Led Lights
Baloncici/Getty Images

Bull Bars

In Australia they’re known as roo bars, and whether their purpose is to protect your car from a collision with a bull, a kangaroo or the back of another vehicle, they can actually damage your car instead of protect it. They transfer the force of the collision away from the front grille to another part of the chassis, and that part may not be designed to handle the force. Besides that, bull bars are heavy, and the extra weight strains the engine.

Bull bars can also create a safety issue. Since they absorb the force of impact instead of the grille, the air bags may not get the signal they need to deploy. One more thing…because they are mounted above the bumpers, they can cause extra damage to any vehicle you hit.

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Male
alfexe/Getty Images

Aftermarket Headlights

These days, most new cars are equipped with LED (light-emitting diode) or HID (high-intensity discharge) headlights. If you’re driving an older model with halogen headlights and want to upgrade, you could run into problems with the electrical system, such as blown fuses and battery drain.

Newer headlights are brighter than older ones, and cars with them usually have sophisticated beam control systems to avoid blinding other drivers. Without proper beam control, you could cause an accident or get a ticket, because some states regulate headlight brightness.

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Keys on a table
Photographer, Basak Gurbuz Derman/Getty Images

Heavy Key Chains

If your car has a keyed ignition, and you’re in the habit of putting tons of extra keys, good luck charms and other paraphernalia on your keychain, you could damage the ignition lock cylinder. That could mean that one fine morning your car won’t start. Besides this, the extra stuff on the keychain can easily scratch the steering column.

Even if you have a push-button ignition, you should limit the extra keys and other metal objects on your keychain. Metal can interfere with the key fob’s radio signal, and the result again is that you could find yourself stuck with a car that won’t start.

FAQs

Will using an accessory that damaged my car void my car’s warranty?

The car’s warranty won’t cover damage that was clearly caused by the accessory. That can sometimes be difficult to prove, and if it can’t be proven, the warranty will still be valid.

Are there accessories that are legal in some states but not others?

Yes, different states have different climates, driving conditions, and safety requirements. Some examples of accessories that are legal in some states but illegal in others include tinted windows, radar detectors, aftermarket exhaust systems and studded tires. Blue and red lights (except for taillights) are illegal in many states because those colors are reserved for emergency vehicles.

About the Expert

  • Joe Giranda is the director of sales and marketing at CFR Classic, specializing in international car shipping and relocation.