Are strut/shock tower braces in compression or bending?

[Ultramaroon]

[RT-BRZ]

I know, this is an old, dead thread. What's the verdict though? It seems as though the Carbing and AEM setups might offer some value. This is keeping in mind that not everyone is running OEM suspension. Solid top hats with spherical bearings in them. Is there still benefit to a brace in that scenario or is the added weight just offsetting any perceived benefit?

I'm asking from the position of running a car with all other suspension bushings being spherical and having the 4 point roll bar in the car that also tightens things up.

[cmiovino]

Originally Posted by RT-BRZ

I know, this is an old, dead thread. What's the verdict though?

There isn't going to be one.

Just my opinion, but strut bars are going to be a thing that's super subjective, even if there's a way to calculate if they do anything.

Take swaybars for example. One person might prefer a stiffer front bar or softer front bar. It doesn't mean X bar is 'faster' than another. One person might prefer even spring rates whereas others seem to like staggered 6k/9k rates.

We can definitely agree the magnitude of the change with a strut bar isn't on the same level as a spring rate or swaybar change... and when those changes are subjective, you can almost toss out strut bars as being a meaningful suspension mod.

With that said, I can say that on my 2004 WRX, the rear bar especially, the rear glass didn't make the creaking noises it did in the very cold over some weird inclines I'd take home from work at slow speeds. Again, not this chassis and even then, it might keep an older car's chassis from flexing maybe a few milometers, if that.

They look cool, so I'll probably add one to my BRZ at some point. The Cusco one weights 3lbs

If we're talking some mid-90's Honda or something - yeah, I think you actually can feel a noticeable difference, even without coilovers. That's how much chassis stiffness has changed over 30 years.

[Racecomp Engineering]

I wrote a little bit about strut bars and chassis bracing here...nothing too groundbreaking.

https://www.instagram.com/p/CjnUih_g...RlODBiNWFlZA==

[RT-BRZ]

Well, I'm going to give it a try. I believe that the worst it can do is about 2-3lbs. of unneeded weight. Given that I already care 30-70lbs. of unneeded weight, I doubt this is going to be much more than a really bad bowl movement.

I bought the Grimmspeed bar. I picked it because of the fundamental integration with the two stock location bars. I figure that it's a completion of triangulation. A big word like that must help.

My review of the Grimmspeed bar is that it gets a 1 out of 5. It is a bar. It has a nice finish. Unfortunately it didn't fit with my fancy stock replacements (were on the car when I bought it. It was more hassle then it's worth so the ole cutoff wheel was brought out to make clearance. It sucks to do it to a new part but it is what it is.

I guess I'll post back my results (if any) for this weekends events.

[cmiovino]

Originally Posted by RT-BRZ

My review of the Grimmspeed bar is that it gets a 1 out of 5. It is a bar. It has a nice finish. Unfortunately it didn't fit with my fancy stock replacements (were on the car when I bought it. It was more hassle then it's worth so the ole cutoff wheel was brought out to make clearance. It sucks to do it to a new part but it is what it is.

The thing I don't love about the Grimmspeed bar is it only attaches to those bolts/points the other two triangulation points attach to. It's similar to the Perrin bar.

This might be ok, but at the same token, it's only those two small bolts attaching it. I like the idea the three strut top hat bolts are used as the attachment points. But hey, I'm not en engineer and Grimmspeed and Perrin are two reputable companies and the other braces attach there, so maybe there's something to it.

I sort of like the DC Sports design, despite it being not a super name brand. It connects to those 3 points, distributing the forces, plus it's a fixed bar unlike Cusco and some others. They're also only $90 shipped.

[RT-BRZ]

Originally Posted by cmiovino

The thing I don't love about the Grimmspeed bar is it only attaches to those bolts/points the other two triangulation points attach to. It's similar to the Perrin bar.

This might be ok, but at the same token, it's only those two small bolts attaching it. I like the idea the three strut top hat bolts are used as the attachment points. But hey, I'm not en engineer and Grimmspeed and Perrin are two reputable companies and the other braces attach there, so maybe there's something to it.

I sort of like the DC Sports design, despite it being not a super name brand. It connects to those 3 points, distributing the forces, plus it's a fixed bar unlike Cusco and some others. They're also only $90 shipped.

Your point is well taken. I would only counter that the Grimmspeed bar does work because of the triangulation is creates with the other two bars. I think it can work properly since there are no pivot joints, just studs connecting the bars to each other in the stack mount style. A final thought there is that it's not a replacement for a lesser bar. It's filling a space that had nothing before. While the impact of its performance may be limited, it's not a lesser solution because there isn't anything in that location anyway.

Note for those with stock suspension; by putting something like this in place, you just move the problem elsewhere in your softer suspension. This is something that goes with coil overs and either poly or spherical bushings.

I can't state for certain that it made a huge difference because I have no idea of how to measure it exactly. However, my car felt really good at our event. I finished at a much higher raw time at our weekend doubleheader than I usually do. Unfortunately (for testing purposes), I had also put on new tires and their grip was such an upgrade over what I had previously (new RE71RS's vs. heat cycled RT660's).

[cmiovino]

Originally Posted by RT-BRZ

I finished at a much higher raw time at our weekend doubleheader than I usually do. Unfortunately (for testing purposes), I had also put on new tires and their grip was such an upgrade over what I had previously (new RE71RS's vs. heat cycled RT660's).

It was definitely the strut bar and not the new rubber
RT660's are.... terrible. I ran them all season in 2022 out to ~230 runs. I was terribly frustrated with them past about 100 runs. My times and PAX scores suffered heavily. Tons of tread, but they heat cycled out quickly.

When I tossed them, they were sitting at our local shop's dead tire bin and someone scooped them up for rollers, but ended up having to run them at an event when something happened with their slicks. They said they were the worst tire they've ever driven on and was spinning tires in 2nd gear with FWD for half of the RPM range lol. He had no idea how I was driving on them.

I'm sure strut bars do something and that something is likely worth the 2-3lbs of weight. That's like a difference of 1/2 a gallon of fuel.

[RT-BRZ]

Originally Posted by cmiovino

It was definitely the strut bar and not the new rubber
RT660's are.... terrible. I ran them all season in 2022 out to ~230 runs. I was terribly frustrated with them past about 100 runs. My times and PAX scores suffered heavily. Tons of tread, but they heat cycled out quickly.

When I tossed them, they were sitting at our local shop's dead tire bin and someone scooped them up for rollers, but ended up having to run them at an event when something happened with their slicks. They said they were the worst tire they've ever driven on and was spinning tires in 2nd gear with FWD for half of the RPM range lol. He had no idea how I was driving on them.

I'm sure strut bars do something and that something is likely worth the 2-3lbs of weight. That's like a difference of 1/2 a gallon of fuel.

The RT660's were fine when they were new. I heat cycled them at a Time Trials event last summer and they were never the same.

I agree about the strut bar. For my setup, it isn't hurting anything. At worst, it doesn't matter.

Oh yeah, gas mileage left the building a while ago. I'm e85 now.

[NoHaveMSG]

Originally Posted by RT-BRZ

I know, this is an old, dead thread. What's the verdict though? It seems as though the Carbing and AEM setups might offer some value. This is keeping in mind that not everyone is running OEM suspension. Solid top hats with spherical bearings in them. Is there still benefit to a brace in that scenario or is the added weight just offsetting any perceived benefit?

I'm asking from the position of running a car with all other suspension bushings being spherical and having the 4 point roll bar in the car that also tightens things up.

I like the design on the nameless strut bar. It uses conical nuts instead of relying on pure clamping load on a flat surface. I don’t think they are worthwhile until you have done bushings and have spherical top hats.

It too, also hate the RT660.

[RT-BRZ]

Originally Posted by NoHaveMSG

I like the design on the nameless strut bar. It uses conical nuts instead of relying on pure clamping load on a flat surface. I don’t think they are worthwhile until you have done bushings and have spherical top hats.

It too, also hate the RT660.

I've gone off the deep end on my car when it comes to suspension. I do agree that if you haven't changed out most of the rubber bushings in your suspension with spherical or, at least, poly then you probably aren't going to see any benefit.

Regarding the fasteners; I wouldn't see a huge benefit from conical fasteners since the whole triangulation setup on these bars ends up in a mechanical bind anyway. Again, you're going from nothing to something across the span of the strut towers so even adding a bar of any kind would help.

RT660's were fine for the price two years ago. Now, I would go with V730's for the price instead. However, on our cars, I think there are really only two viable tires for autocross (Bridgestone and Yokohama) if you want to be on the pointy end.