What does a strut bar do?

A strut bar is a stiff metal bar that connects your front and/or rear strut towers with the purpose of adding more rigidity to your car. Its effectiveness, however, all comes down to your car.

We’ve seen strut bars make a big difference on older cars that are prone to chassis flex and/or body roll issues. While others are more like a non-functional cosmetic upgrade – all for show with no real benefit to handling.

Read on as we dive deep into the mechanics of strut bars, what they do, along with their pros and cons.

The Strut Bar Explained

A strut bar also called a strut brace or strut tower brace is a connecting rod that laterally (from left to right) links your suspension strut towers. This reinforces your chassis by tying these two stress points together.

A BMW 123i with M3 strut tower brace
A BMW 123i with M3 strut tower brace. Image: 135i Engine Bay, freshly detailed by gsloan, CC BY 2.0

You’re probably wondering “what are strut bars for?” Well, strut bars were primarily designed to overcome limitations of the MacPherson Strut type suspension system. However, this doesn’t mean that cars with other types of suspension setups cannot benefit from strut bars.

Unlike double wishbone type suspension systems, MacPherson Strut assemblies are load-bearing on the top — where they’re connected to the body of your car.

Because of this design, your strut tower undergoes extreme pressure while hard cornering or if you hit a bump at high speeds. This pressure is enough to offset and temporarily change the alignment of your suspension geometry, making your car unpredictable in tight situations. Installing a strut bar helps to counteract this effect.

How Does a Strut Bar Improve Handling?

There has always been an interesting contrast between handling and performance. Handling refers to how the car feels and how stable it is, while performance has more to do with speed and acceleration. Generally, cars that handle well are easier to manage at high speeds.

The main purpose of a strut bar is to make your car easier to handle when being driven hard.

Strut bars won’t necessarily increase your cornering speed or lap times. Instead, they’ll make your car more playful and predictable when cornering at speed.

This is the result of the strut brace redistributing excess pressure from one strut tower to the other. This significantly reduces chassis flex through tight corners and helps to keep your steering stable even at high speeds.

Installing strut bars increases the overall rigidity of your car. Because of this, your chassis doesn’t flex when you hit a bump or if you’re turning hard into a sharp corner.

Strut bars improve handling while drifting and cornering hard

Front vs Rear Strut Bars

Most enthusiasts claim that you need to be an experienced driver to notice the real difference that front and/or rear strut braces make.

To maximize the effectiveness of your strut braces, you need to combine them with aftermarket bushings and ball joints. Add a pair of sway bars to that list and you’ll dramatically change the handling of your car.

Strut braces can be installed either on the front or rear strut towers. Stiffening up the front end of your car will increase understeer and doing the same for the rear end will increase oversteer. However, this heavily depends on the current handling characteristics of your car.

A Cusco rear strut tower bar installed in a Toyota GT86

You can either install both or just one, depending on what you’re trying to set your car up for.

Strut Bar Pros & Cons

Just like every other car modification, strut bars come with a few advantages and disadvantages. We can’t conclude whether strut bars are either good or bad because this depends on the driver and car in question.

Either way, they’re a really interesting little upgrade and will make a nice addition to your list of mods. Here’s what makes strut bars great and what doesn’t.

Strut Bar Advantages

Stiffer Chassis

We cannot deny the fact that some cars really do benefit from strut bars. These include old, light-weight cars that are known for having body-roll and sway related problems.

If your car is new-ish and doesn’t have any stiffness related issues, you won’t benefit from installing strut bars.

Reduced Wear and Tear

Strut bars redistribute tension between the left and right strut towers. All the force and pressure that is generated while driving gets shared evenly across your chassis.

Because of this, the wear and tear associated with this pressure also get redistributed. Even wear is always a good thing.

Under-Hood Bling

Let’s face it, many enthusiasts install a strut bar because it makes their engine bay look great — and that’s okay. As long as the mod has some function and doesn’t take anything away from your driving experience, it is worth installing.

Tastefully painted or anodized strut bars look fantastic!

Tanabe front strut bar installed on an Infiniti G35

Easy to Install

Installing strut bars by yourself is a piece of cake as long as you’ve purchased the correct unit. Because they’re all made specifically for each application, you won’t have to whip out the drill machine or any cutting tools.

This installation can be done in your driveway, without needing to jack your car up. Simply clean up the strut tower area and unscrew the existing nuts. You’re going to have to use the same bolts to fit your new strut bar.

Before bolting on the strut bar, check if there’s enough clearance with the hood. Once done, simply bolt it on without over-tightening the nuts and you’re all set.

Affordable

Strut braces range from under $100, all the way to three digits. Which one to purchase is entirely up to you.

Cheaper strut bars are just as good as the expensive ones, as long as you choose your design and construction carefully.

Strut Bar Disadvantages

Off-Road Performance Takes a Hit

In some cases, your suspension needs to function independently. Especially if off-road stability is important for you.

For example, if you have a strut brace installed, and your front left wheel hits a bump, this effect will also be felt on the front right wheel. The same problem occurs with sway bars too.

This isn’t ideal when it comes to driving off-road. You could lose traction when you need it the most and your ride will be uncomfortable.

Makes No Straight-Line Difference

Strut braces can only be taken advantage of when going around corners or while steering over uneven surfaces.

If you’re driving in a straight line or racing at a drag strip, your strut bar won’t make a difference.

Strut braces aren't necessary for drag builds.
Strut braces aren’t necessary for drag builds. Photo: MM’08_350Z

Occupies Engine Bay Space

Your strut bar shouldn’t block any important access points such as your or battery.

Make sure that your hood doesn’t hit the strut bar when it’s shut. In some cases you may need to adjust the height of your hood after installing a strut brace, so research each product thoroughly before buying.

Form Over Function

We love modifications that look great and actually serve a purpose. That said, strut bars aren’t a “cosmetic only” mod by any means. They do serve a purpose but most people install them for the looks.

We consider strut bars to be 25% function and 75% form. It really depends on what you’re trying to accomplish.

If you’re expecting a drastic change in the way your car handles after installing strut bars, you’ll probably be disappointed.

Strut Bar Construction

Whether or not a strut bar does what its supposed to also depends on its construction. If it flexes more than your chassis does, it won’t be of much use.

Some of the cheaper strut bars come with brackets that get bolted on to your strut tower first, then the bar gets fitted on to these brackets (which tend to break). This is the design you must avoid because your strut bar is only as strong as its weakest point.

When it comes to material selection, steel is your best option. If you’re going for an aluminum strut bar to save weight, make sure it’s bulky and strong enough to actually work without flexing.

You must’ve noticed how steel has always been the metal of choice for building roll cages and frames. This is done for a good reason; the combination of affordability, high-tensile strength and rigidity makes steel the preferred material for making parts that are going to undergo a lot of stress.

Do Strut Tower Braces Work?

Whether or not a strut bar will work for you really depends on what car you drive. Not all cars need or even benefit from these.

Quite honestly, if this is going to be your first modification, we recommend purchasing a rear sway bar first; especially if better handling is what you’re after.

These days, most modern cars are quite torsionally rigid and don’t require any additional reinforcement. Adding a strut brace to these cars won’t really make a difference. It’s the old ones that can really benefit from this upgrade.

What’s your take on strut bars? Do you think it is worth installing them? Leave us a comment below!

 

Feature Image: Cusco Strut Tower Brace, and Angle Support system, with, Brake Master Cylinder Stopper, and Oil Catch Tank by Moto Miwa, modified by Low Offset, CC BY 2.0

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