Strut Bar Purpose – Will You Feel The Difference?
Strut bars are one of the cheapest performance parts you can buy and strut bars are also available with a huge variety of designs. But what is the strut bar purpose? Why fit one? What can you expect & are they worth the money?
What does a strut bar do?
Short answer, it makes the shell of the car stiffer
Why is this good?
Keeping the body shell of the car in the shape it is supposed to be ie not flexed, the suspension can work the way it was designed to
Why does the suspension not work as well if the body is flexed?
The goal of the suspension design is to keep as much of the tyre in contact with the road as possible in all conditions ie cornering, braking and acceleration. If the body of the car is flexing the suspension mounting points will be moving in relation to each other which means the amount of tyre in contact with the road will be compromised ie there will be less grip
Why doesn’t the car manufacturer make the body stronger?
Ultimately it’s because of cost. If cost was no object, like in a WRC car, the flex can be minimal due to the roll cage. A road car on the other hand is built to a cost. The car manufacturer will make the car as stiff as they think they need to for the average driver and for the budget they have to build the car. For drivers who demand more from the car than the “average” driver and/or for owners who fit better suspension and/or grippier tyres, the body will flex more than it will for the average driver. If the above average driver wants better performance they can fit a strut bar to keep the suspension mounting points closer to the optimum.
Is extra body stiffness noticeable?
This depends on the driver and the car. In my experience a strut bar can make a noticeable difference.
What is the difference with a strut bar?
In my experience the difference can be a more comfortable ride, better turn in, better steering feel and more grip, these are the strut bar purpose.
Which type of strut bar should I choose?
Strut bar is a blanket term. I think a more accurate term would be body/chassis strengthening. There are three main types.
Strut tower bars are the ones you can see. These are the most popular and most readily available. These connect the top mounts of the damper/struts to each other. You can see them going across the top of the engine. Some strut bars have two mounting points ie one on each strut tower. Better strut bars have three or maybe even four mounting points. The three point bars connect to the strut towers and also form a triangle which connects the strut towers to the firewall at a central point. A four point strut bar may also make an additional triangle that link the strut towers to the slam panel but these designs are rare.
Strut tower bars can also be found for the rear strut mounts but generally these are the two point type.
Wishbone Bars/Lower Strut Bars.
These bars connect the mounting points of the wishbones underneath the car together. These are generally cheaper than the strut tower bars because they are smaller. These are also not as common as the strut tower bars.
There are bars from companies such as Cusco and Ultra Racing that will make three or four point lower strut bars. These tie the wishbone mounting points into the sub-frame at additional points.
These are mounted to the body shell itself. There are a huge variety of products in this area but generally they are available for a smaller selection of cars. These bars include bracing which secure the front top mounts to the a-pillar, bars which tie together the seat belt mounting mounts across the car inside (some may even double as harness bars) and bars which mount underneath the chassis linking points either side of the transmission/exhaust tunnel together.
Which One To Choose?
I’d probably start with the strut tower bar because these are the most common. After this I’d go for a lower bar. These two before the others because I think they will probably have the biggest effect. After that and if there are other braces available, any order you want.
If there are more than one type of brace available for your car, personally I would one bar at a time so you can feel what difference each one made.
Strut Bar Purpose – Generally Speaking
Anything that keeps the chassis stiffer is a bonus for grip because the suspension is kept closer to its optimum geometry for more of the time.
This is a question I hear a surprising amount and generally speaking I think the people who are asking this question should not bother fitting a strut bar.
The conversation goes something like this.
“If I fit a front strut tower bar and I have an accident on the right side, is the car going to get damaged on the left.”
In my opinion there is absolutely no way to answer this because every crash is different.
What I would say is that logically speaking, I believe when you make a car stronger you are making it safer. Roll cages are put into competition cars primarily for safety, the performance benefit is an added bonus.
I would also say that if a car has more grip, more of the time it is less likely to get into an accident in the first place which is also safer.
And finally, as with any modification, you should tell your insurance company, if they have no issue with fitting a strut bar then I think the car owner should probably not worry about it either.
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