Everything You Need To Know About Car Fender And Bumpers – A Comprehensive Guide

What Is A Car Fender And What Does It Do?

Some car parts have nothing to do with the mechanical aspect, but are just as vital as the engine, transmission, and suspension. Car fenders and bumpers are two of those parts. They don’t affect speed and performance but are critical to the car’s safety. So, what is a fender, and what does it do?

Car fenders have changed radically since the first automobiles appeared on the road, but their function has remained the same. They are designed to prevent stones, mud, and other debris thrown up by the tires from damaging the car’s bodywork or hitting nearby objects and people.

While many people are confused by the difference between fenders and bumpers, they aren’t the same thing, and their protective roles are quite separate. To clear up any confusion, let’s take a close look at each, how they’re made to perform in a modern car, the materials used in their manufacture, and how we can ensure that they stay in the best condition to do their job.

What Is A Car Fender, And What Does It Do?

What Is A Car Fender And What Does It DoLooking first at car fenders, they can best be described as the part of the bodywork that covers the front and rear wheels of the car. “Fender” is an American English term, and even in some dictionaries is confused with “bumper,” which is not the same thing.

In a modern car, the metal fender is a panel forming an integral part of the bodywork. The front fenders are positioned in front of the door panel, and the rear fenders are behind the back doors. They cover the wheel arches and are protected by fender liners from all the dirt and debris thrown up by the tires.

If you’ve watched Formula One motor racing, you will have seen the plume of spray thrown up by the cars on a wet track. This is because these cars have no fenders on the rear wheels and only very small “mudguards” over the front pair.

In the old days, the fenders were separate body parts, attached to the car’s sides with metal stays and protruding over the wheels (check pictures of the Ford Model T to see an example).

Without fenders, depending on the speed at which the car is being driven, the stones, rocks, mud, and spray thrown up by the tires could cause serious damage to following vehicles, injure people hit by these objects, and damage the car itself with every impact of debris on the bodywork.

The Difference Between A Car Fender And Bumper

Difference Between A Car Fender And BumperWhile the fender is situated on the car’s sides, over the tires and wheel arches, the bumpers are at the vehicle’s extreme front, and rear ends.

Car Fender Vs. Bumper

The difference between the fender and bumper is that the fender is not designed to protect the car from damage in a collision and is usually one of the most vulnerable parts. You’ve heard the expression “fender-bender” applied to minor damage caused by a light impact. That’s why one of the auto body parts most searched for is a replacement fender – it’s usually cheaper to replace than repair.

The bumper, conversely, is specifically designed to protect the car from the front- and rear-end impacts. Bumpers used to be metal or chromed bars bolted to the car, but modern cars now have plastic bumpers integrated into the bodywork, which might look better but don’t provide much protection.

Another role of the bumper is that it provides protection, not for the occupants, but for pedestrians who get knocked over in an accident. Car designers have gone to great lengths (often compelled by law) to ensure that the bumpers minimize injuries to those who get hit by a car in an accident.

Fenders And Bumpers – Materials Used In Their Construction

Now that it’s clear what the difference is between fenders and bumpers, the various materials used in their construction can be better understood.

Material Used In Constructing Fenders

Except lightweight performance cars and most kit cars where fiberglass is used in construction, a car’s bodywork is usually made from light steel. Steel fenders are preferred because of the strength of the material, its durability, and the fact that it’s easily shaped.

The alternative material for bodywork, including the hood, trunk lid, and fenders, is aluminum. It’s much lighter than steel, which is why you’ll find it used by BMW in their sports cars, and it’s extremely strong, hence used in the construction of Land Rovers. The disadvantage of aluminum is that auto body repair shops often need to train repairers who can handle this material.

Materials Used In The Construction Of Bumpers

Bumpers are required by law in the US. As mentioned,  they protect pedestrians and reduce the damage caused by low-impact collisions. Until the 1960s, bumpers were made of steel, often chrome-plated and highly decorative.

Modern bumpers are plastic covers over bars made of steel, fiberglass composite, aluminum, or plastic. The cover may also be made of fiberglass. In the case of plastic bumpers or fiberglass bumpers, they are often filled with a polystyrene foam core which absorbs most of the impact while minimizing the danger of injury.

The exception, of these injuries-reducing bumpers can be found on SUVs and off-road vehicles where the owners often fit heavy-gauge solid steel “bull bars .”These are designed to protect the car if it collides with trees, animals, and other off-road hazards, but they often are used to create an image of ruggedness. Surprisingly, because they can be extremely dangerous in a collision, there is no law in the US preventing bulling bars from being fitted.

Tips for Keeping Your Car Fenders & Bumpers in Good Condition

Car Fenders & Bumpers in Good ConditionKeeping your car in tip-top condition may cost you initially, but by maintaining auto body parts that get damaged from time to time, you will preserve the value of your car and get your investment back when you decide to sell.

Keeping Fenders In Good Condition

  • The simplest tip is to keep the fenders clean (with the rest of the car). With road dirt building up in the wheel arches and on the fenders, particularly in winter, the risk of corrosion and rust increases. Spray this dirt off regularly and protect the metal with a silicone polish.
  • Fenders get scratched and damaged even if you don’t have an accident – parking lots are notorious for this. Particularly if your car has flared fenders, try fitting plastic or rubber fender guards, which usually attach with a press fit to the edge of the fender.
  • Another helpful car repair tip is to protect the fender with a plastic sheet when working on the engine bay. This will prevent spills of coolant liquid, brake fluid, or oil from damaging the paintwork.
  • Suppose you are unlucky enough to have a fender-bender; get the damage repaired by an auto body repair specialist as soon as possible. In that case, damaged paintwork can lead to moisture contacting metal, and rust may follow.

Maintaining Bumpers In Good Condition

  • Many bumpers are color-coded, meaning they have been painted to match the bodywork. They look great until scratched, and the black plastic shows through. If the blemish is minor enough, a touch-up with paint supplied by the manufacturer or a good auto body repairer should be sufficient to keep the car looking pristine.

  • If your car has black plastic bumpers, they tend to fade to an ugly gray quickly. Don’t wax them, as this leaves a white residue. Instead, used boiled linseed oil to restore the color and shine.

  • If the bumper has been cracked or deformed in a minor incident, you don’t have to replace it. Some specialists repair plastic bumpers, and it’s relatively inexpensive to get your bumper looking good and back to protect the car.

How To Choose The Right Replacement Fender Or Bumper

If the damage to the fender or bumper is too severe to repair, replacement is the only alternative. But there are ways to reduce the cost, which may save you a lot of money without diminishing the value of the car.

Replacing a fender can be costly, especially if you’re driving, say,  a luxury German or Italian exotic model. You can search for a second-hand fender and compare the cost with the price quoted in the manufacturer’s auto body replacement cost guide. You may save up to 50% 0f the price, and if it’s undamaged, the replacement part needs to be sprayed to match the bodywork.

It’s not a great idea to buy a “pirate” or aftermarket part. From experience, the fit is always a few millimeters out, the quality is not as good as the original, and it will be noticed by a dealer when you want to sell or trade in the car.

Replacing A Bumper should be considered if the bumper is badly damaged, if the impact bar has been distorted and if its effectiveness in the future has been compromised. 

New bumpers can cost anything from $100 to $1000 and more, depending on the make, model, and age of the car. Labor costs in removing the damaged bumper and replacing it will also be considerable. Check whether your insurance will cover the cost or whether the excess makes it more economical to carry the price yourself.

Because the quality of the bumper can make all the difference in a serious accident, it’s only advisable to buy an aftermarket product if an independent expert approves it.


Fenders and bumpers are two very different auto body parts, but each plays a vital role in protecting the car and its occupants. While there is some confusion in defining the two, and in some countries, the two names are interchangeable, we hope we’ve given you a better understanding of precisely what they are and what they do.

To recap, fenders protect the bodywork from flying dirt, dust, mud, and road debris while also preventing these from hitting other cars and pedestrians. Bumpers are designed to minimize front and rear damage to a car in the event of an impact and are shaped to inflict less injury to anyone hit by a car in an accident.

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