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Is a Strut Brace Worth It?

When it comes to car modifications, strut tower braces have been the topic of many a great debate on the Internet. Whether for street use, track use, or additional chassis reinforcement on an already stiff and caged race car, the question always comes up: Is a strut brace worth it?

Yes, you need a strut brace!
“Yes! You need a strut brace. Trust me! You’ll feel it working!”

There are those who will argue to the e-death that they can feel a noticeable improvement in chassis stiffness and suspension control with a strut tower brace installed, and there are those who refuse to even look at strut bars because they believe they’re nothing more than engine bay bling and eye candy. There’s plenty of conjecture, but it’s extremely hard to find any actual facts to back up claims from either side. Since we love to have actual data to make an informed decision or recommendation, we turned off the proverbial butt dyno and decided to measure the actual amount of strut tower deflection on a BMW. What can we say? We like to go the extra mile – and we like learning just as much as we like sharing knowledge.

No, strut braces don't do anything!
“No! A strut brace is a worthless piece of eye candy. I couldn’t feel anything!”


When in doubt, test!

Spec E46 testing
Our Spec E46 330i was the test subject

While plenty of people like to run strut tower braces on street cars, we wanted to get measurements on something that would see much more severe duty, so our test car was our BimmerWorld Spec E46 BMW 330i, and we used both Lime Rock Park and the full course at Virginia International Raceway (VIR). VIR gave us the most usable data since it has elevation change and some significant high-loading features that really put a chassis through a workout. Plus, it’s our home track, and we’re intimately familiar with the layout.


Testing was conducted without a strut bar in place to determine “the problem” that a strut bar would otherwise solve. Nick Large, BimmerWorld’s Product Development Engineer, configured the onboard AiM MXL2 data system to include linear potentiometers in several locations/configurations to measure distance changes between points. After recording on-track data, we filtered out some level of noise with an exponentially weighted moving average, or for those of us who aren’t engineers, that means data smoothing, which gives us a cleaner look at the data. You can see the results in the graph below.

BimmerWorld SE46 Strut Tower Deflection Data from VIR
(Click image to view the full-size graph)

The Delta Distance on the graph measures the change in distance between the tops of the strut towers, so a positive number means the towers are spreading apart while a negative number means the towers are getting closer together. Note that the measurements are in millimeters, or more specifically tenths of millimeters. As a rule of thumb, the distance increases during cornering because the load on the tire is twisting the top of the inside tower away from the vehicle center line, and the distance decreases under braking and over bumps because the towers twist simultaneously and in opposite directions. If you know the layout of VIR well enough, the annotations allow you to understand the trends and see how they correlate to certain sections on the track.

The data was gathered over many laps, with every lap showing incredibly consistent deflection numbers, and as you can see, the movement in this measurement location is minimal on this particular car. A strut bar, or any other structural member, provides strength almost exclusively in this tension/compression range, and most E30/E36/E46 BMWs exhibit movement purely laterally across the strut towers, as our measurements reflect. Further testing of additional locations showed similar minimal movement, although those locations wouldn’t typically be affected by an aftermarket strut bar regardless.


So, is a strut brace worth it?

That brings us back to the main question: Is a strut brace worth it? The scientific answer is, “It depends!” Based on the data from our specific Spec E46, this car didn’t need one on this particular test day.

But that isn’t the comprehensive answer, and from experience, we know there is a need in some cars. Why is that? BMW is iterative in their chassis design, and part of the added weight of each new chassis is the added stiffness. The older, lighter, and more flexible E30 definitely needs a strut brace, which we know from the high number of racers with collapsing strut towers that are actually pushing together with age; a strut tower brace solves this! And one hard concept to accept is that everything wears out over time, including the metal chassis of a car, so even newer models will likely head down this path eventually with enough mileage, age, and pounding on the street or track.

We’ve also seen other E46 cars bend strut tower braces, which was the catalyst for this experiment, so there is clearly something moving. But remember, standard strut braces help in tension and compression, not bending, so while there is movement, a strut brace really didn’t help much in the cars where we saw damage. And why was there movement? The example cars we saw had been hit previously in the front, weakening the spot welds or sheet metal. If our test car were older, in worse shape, or if it had any broken spot welds in the strut tower, then a strut brace would help.

People ask why we don’t recommend strut braces for all cars. Easy answer – not every car requires one, and we don’t believe in pushing products you don’t actually need. But there are certainly situations where BMWs benefit from having a brace.

E46 strut tower brace

So, what about installing a high-quality, single-piece strut brace like the Rogue Engineering Race Brace to simply add reinforcement to the strut towers – the prevent a problem before it happens approach? That could certainly be a benefit, as it may very well help to disperse the energy from potholes, bumps, and severe cornering loads (especially when running camber plates). Anything you can do to help distribute loads and avoid deformation of the strut towers is a plus, but there are less expensive ways to do that if you don’t need a strut brace – BMW’s factory strut tower reinforcement plates being a prime example. The minimal movement shown in our test graph proves to us that a strut brace would be most beneficial if you have an older car or tired chassis with noticeable flex and/or pre-existing issues. Then you may get the intended benefits of the brace with the added insurance against strut tower deformation.

Ultimately, we’d like to perform this same test after five years of racing with this car. While the movement in our graph is minimal, it may certainly be enough to have a fatigue effect over time. According to James Clay, who once had his finger stuck between the main hoop of a cage and the B-pillar for part of a lap by accident (ouch!), this would likely be no more fatigue than the entire metal chassis of the car would suffer from. So it becomes a question of the added weight from an extra part (weight is normally considered the enemy) versus the potential long-term benefits. That’s not as easy to answer.

6 Hours on The Ridge BimmerWorld

6 Hours on The Ridge – 2016

Talk about living the good life. That’s exactly how it felt at the 6 Hours on the Ridge, spending a great weekend with our friends and customers. The Ridge is a relatively new facility that opened in May of 2012 in Shelton, WA, and it’s got a great track layout with an amazingly scenic view; we were treated to a snow-covered Mt. Rainier as our backdrop for the entire weekend.


A weekend at the track means a weekend with friends

When we’re not in the BimmerWorld office, we all like to get out and spend time with the BMW community, and that often involves heading out to club events, track weekends, and races all over the country. James Clay, BimmerWorld president and complete track junkie, can often be found digging in with friends and customers trackside to help with car setup and share some of his own learning experiences. Not only do we get to hang out, we can give back and get first-hand experience with what issues people are having and what trends or region-specific needs we can help with. These weekends also give James a good chance to spend time with several of our BimmerWorld dealers around the country. The weekend at The Ridge was no exception, giving the perfect opportunity to visit with a few BW dealer friends in the Washington area, like Advance Auto Fab, Bristow’s Exclusive Auto Repair, Grip Racing, and Lowe Group Racing.

Anyone who’s met James or spent any time with him learns immediately that the cars, track days, racing, and motorsports in general are just an elaborate excuse to spend time with the people as much as anything else. It’s really all about the time we get to enjoy with our friends, whether on track or off.


AiM Data – School’s in Session

Saturday was all about testing, and all the teams were working on getting dialed in with the track and car setup for the 6-hour endurance race on Sunday. The highlight was the Saturday evening data acquisition seminar put on by our good friend and occasional substitute driver for our pro team, James Colborn, along with help from BimmerWorld drivers James Clay, Dan Rogers and Seth Thomas. The group put on a much-appreciated lesson, sharing the fundamentals of working with data in a racing environment, specifically with the wildly popular AiM Solo. This also marked the start of several data seminars Colborn will be presenting through the Conference season.

James Colborn AiM seminar
James Colborn teaching everyone the intricacies of data acquisition and what to do with the AiM-sourced data once you have it.

ICSCC, or “Conference,” is the International Conference of Sports Car Clubs made up of several sports car clubs in the U.S. and Canada, making the largest racing sanctioning body in the Pacific Northwest. This also happens to be the first sanctioning group to adopt Spec E46, so they obviously know the makings of a good race class when they see one.

6 Hours on The Ridge with close Spec E46 racing
There was plenty of good, close Spec E46 racing at every turn of the 6 Hours on The Glen enduro. (Photo courtesy of Doug Berger – scroll down for gallery.)


Spec E46 Continues to Grow – And Win

Sunday was the big 6 Hours on the Ridge endurance race where it was once again proven that Spec E46 is a solid racing class that’s here to stay with constantly growing numbers. It was a great turnout with nearly 30 teams spread out among various classes, and BimmerWorld’s Dan Rogers finished at the top of the podium for the second time in three years at this same event.

The racing was great, the track and facilities were perfect, and the surroundings were breathtaking, but the real highlight was spending an entire weekend on track alongside our friends.

6 Hours on The Ridge with James Clay and man's best fan
It doesn’t matter how soon the green flag is going to drop, there’s always time for extreme closeups of dogs. (Photo courtesy of Doug Berger – scroll down for gallery.)


Race Gallery by Doug Berger

Event Gallery by James Clay


BimmerWorld Partners with American Endurance Racing

Dublin, VA (March 29, 2016) — BimmerWorld, with a long history of both successful racing and customer racing support, will be teaming up with American Endurance Racing (AER) again for the 2016 season.  

AER is one of the great new endurance racing series that provides a great place to race a BMW, so the partnership is a natural fit. “AER is the perfect venue for a lot of our customers, and we are excited to be involved as a sponsor for the full 2016 season,” says James Clay, BimmerWorld team owner and president. “The formula of inexpensive team endurance racing in well-sorted and quick but not overly expensive equipment is compelling. We have run fun bang-for-the-buck cars for well over 10 years at the club level, to be both competitive and entertaining.  AER has found a sweet spot for where those two goals meet, and we are excited to be involved again this year.”  

In addition to providing contingency support for BMW teams in the field, BimmerWorld will campaign their own BMW 325i endurance car in selected events. “As we launch this new program, our BimmerWorld staff racers who primarily focus on the office side of the business, with the support of two of our technical partners, will be running under the BimmerWorld Red Line Oil Racing with OPTIMA Batteries featuring Nick and Phil banner,” explained James.

“While we may not be using the staff and equipment of the BimmerWorld pro team, this isn’t our first rodeo.  We know from watching teams like Rahal Letterman Lanigan, Target Chip Ganassi Racing with Felix Sabates, and Team TC Design featuring Mark Drennan that even without rolling our transporter, if we have the longest name in the field and bring along our great friends and supporters like OPTIMA and Red Line Oil, we are sure to make the intended splash as we participate alongside our friends and customers in this awesome series.”

The 2016 AER season starts April 22-24 at Watkins Glen, and more information can be found on the AER website (, or call the professionals at BimmerWorld to discuss your next track adventure.


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