Cusco vs. Corksport Strut bars
 

Just wondering if there is a large quality/stiffness between the two brands products.

I've got the Corksport. Its made of aluminum and steel. Unless the Cusco is carbon or titanium then I doubt there's much difference. Don't pay for a name.

Chris

Ditto, the Corksport ones are very good quality.

I've heard the Corksport bars referred to as "flexi-flyers."

is there REALLY any difference between like ANY different strut bars? (except maybe the solid ones... ?) I can't see how one piece of alluminum can be that much different than another...

Well I wouldn't call the Corksport ones that. Maybe some of the $5 eBay ones, but the Corksport ones were modelled after the Cusco ones, and are plenty stiff.

well, i have the cusco bars.. front and rear, uppers and lower... and rear tri-bar.... they are excellent quality... never seen the coksport.. but they seem to make quality stuff... so its really up to you

i have the Corksport Front an rear with stock sus. and it works great.. :)

ive used egay bars, and worked fine.

I have the CS front. The car understeers like a pig with it (old stock suspension), so try to get the front and rear

edit: i'll sell you mine if you want

I have an ebay bar on my piece... don't see how it could work any better... they all fit the same way.

well, alot of ebay ones are made from inferior metal/aluminum.... the point of a strut bar is to stop flex and swaying of each strut tower under hard cornering... low quality bars will still flex... basically rendering them useless

how would stiffening up the front would cause understeer?

cuz thats how it works. just like stiffer springs in front increase understeer.

generally, stiffer in front = more understeer. stiffer in back = more oversteer.

I still find it seriously hard to believe that just because one bar is made of slightly better alluminum its going to make a noticeable difference... is there any alluminum bar thats not still going to flex just a little bit?
I'd like to hear from someone who's actually used both and compared them.

unicorn_squad cuz thats how it works. just like stiffer springs in front increase understeer.

generally, stiffer in front = more understeer. stiffer in back = more oversteer.

I still find it seriously hard to believe that just because one bar is made of slightly better alluminum its going to make a noticeable difference... is there any alluminum bar thats not still going to flex just a little bit?
I'd like to hear from someone who's actually used both and compared them.

hes talkn about strut bars not springs i dont think a strut bar would cause a noticeable amount of either over or understeering but make it handle more consistant bcs frame flex and twist happensunder diffrent amounts of load and the frame doesnt move at the same rate for the amount of flex

It certainly does make it understeer more. I have both corksport bars and I put them on one at a time to see just how the car would react. The front one will make steering response a shitload faster but also understeer more. Both certainly help balance the car out more but unless you get camber plates in the front then its gonna want to understeer no matter what. Unless you fuck with the sway bars too.

Chris

strut bars probably won't be as noticeable as spring rates, sway bars, or shock adjustment, but it still is going to make some difference in the same way those other things will...

what im tryn to say is when the springs and shocks move faster then there limit the shocks will pack and its going to twist the frame more then it would with the shocks moving at a slower rate and with a sturt bar in place it will isolate the shocks from the frame making for a more consistant steering input

right, noone's saying it won't do that, but it will also increase understeer for the same reasons stiffening anything else on the front of the car will.

if u want a flawless style frt bar go with the racing beat upper bar the solid bars give no flex while any that are bolted at the flange can and will give at the bolt.. but IMO the corksport and cusco seem fine..

I used ebay bars on my civic and they worked fabulous

The eBay bars aren't less stiff because of inferior materials. ALL steels and ALL aluminums have the same stiffness, plus or miunus LESS than 5%. The differences will come in the designs. The Corksport bar is wider with good flanges on the strut top connectors. Most of the eBay bars are thin and have very little material at the flanges, which leads to increased amounts of flexing.

It's the design, not the material that makes one bar stiffer than another made with the same material.

The only way to go is triangulated.

i built my own strut braces, front and rear...
took some time, but they were 100% free :D
made them to fit perfect, and they work absolutely great! very noticeable difference!

made them out of steel, cause that was the only material at hand (translate: free for the taking). they are also strength adjustable using left and right threads

now at my new job i have access to a lot of aluminium, so im going to modify the rear and fabricate a complete new one for the front.

absolutely going triangular in the front!

front:
http://partyaddict.xszone.net/furb/m...ontstrut_3.jpg
http://partyaddict.xszone.net/furb/m...ontstrut_8.jpg

rear:
http://partyaddict.xszone.net/furb/m...earstrut_5.jpg
http://partyaddict.xszone.net/furb/m...earstrut_7.jpg

Wow! real nice. Have you thought abt making more of them and selling them in the forum?

Not true. I'm not sure what property you mean when saying "stiffness" but in tensile/ compressive strengths (which is what one would have in a strut bar for the most part) there is a vast difference in specs depending upon the alloy used. Aluminum alloys can range in yield strength from roughly 100 MPa in 1000 series aluminums to over 150 MPa in 3000 series. 300 series stainless steels (which is only one type of many SS's, which again is only one of many many different types of steels) can range from a tensile strength of 700 MPa to over 1550 MPa with just some cold rolling.

I'm not saying everyone should go out and buy the most expensive strut bar they can find, but materials are still something that one might want to consider before making their purchase.

Does anybody make a flat bar style for fc/t2's? Im not a big fan of tubular style like the Corksport and Cusco

n/m, after going back and looking, the cusco is flat bar and the cork is oval it looks like. dont know why i thought both of them were tubular

no not really, just because i live in Holland... shipping would be killing! specially for the steel version, it weighs a LOT! that's why im going over to aluminium ;)

Yield strength is the measure of the amount of stress (force over area) that a material can take before yielding (permanently deforming). That varies a great deal, and has nothing to do with how stiff it is (how much it'll deflect before yielding).

Young's modulous (E) is a measure of how much a material will deflect for a given stress. That is nearly constant for aluminums and steels (steel being rougly 3x stiffer, but also 3x heavier). That is what I was referring to as stiffness, because for any steel or aluminum bar of a given weight under the same loadings, the bars will all deflect about the same amount.

Stiffness is practically constant for any alloy made of a given material.

Indeed the young's modulous is roughly the same for these materials, but wouldn't you treat a strut bar as a 2 force member (obviously triangular ones are different)? In that case, the strength of the material would be important. Or should I be looking at this problem more from a buckling column standpoint? I'm still a student, so if you could help me work through this I'd appriciated it.

Buckling should be considered also, but the strength of the material is really only improtant for failure, either from excessive force, or from fatigue. But since it's a long, slender column buckling will occur long before yielding will, so it's not really that important what the ultimate or yield strengths are. In terms of chassis rigidity the relevant thing to look at is the young modulous, because you're trying to reduce flexing, and a stiffer bar does that, a stronger bar doesn't necessarily do that.

In terms of how you'd model it, it's a truss, it accepts only axial forces, because it's pinned at either end, so it can accept no moments or non-axial forces.

I'm also a student, I'm in my last half of third year of my Bachelor of Mechanical Engineering degree.

You are about the same place I am in school lol.

I'm just not seeing how the Young's Modulous is as big of a deal. I'm basically approximating the bar as a 2 force member (in a truss), since in can only really effectively transmit force transversely along the car. Following that assumption, lets take a look at this. I'm not seeing quite what you mean by flexing... there will really be only one kind of deformation going on, the axial deformation, or compression from the car during a turn, of which the buckling would be the ultimate failure mode.

black91- i'm sure you've seen this stuff but I'm gonna try to explain it for everyone, any input/corrections are fine by me

I'm gonna use the Johnson curve to model the buckling failure. This curve is a modification to the Euler Curve which is modeled by the following

P/A = Cpi^2E / (l/k)^2

where P is the load
A is the x-sectional area
C is the end condition factor (basically = 1 here)
l is the lenght
k is the radius of gyration
E is Young's Modulous

The Johnson curve takes the Euler one a step further and fits a different curve that eventually intersects with the Euler Curve. The Johnson equation is the following:

P/A = Sy - (Sy*(l/k)^2) / 2*(T)^2

T is the intersection point of the 2 curves at Sy/2 = Cpi^2*E/T^2
Sy is the yield strength

Anyway, you would set these equations up and solve for the x-sectional area.

I'm saying the strength matters based on the 1st part of the Johnson equation, which would be the ultimate failure and the manner in which the part would flex before completely buckling. I don't think you would see much purely axial deformation unless the brace had a amazingly designed mount.

That said, I doubt the car can load the brace up enough to even approach the critical load of steel, which is why aluminum would be used, and even then its probably nowhere near the critical load for that either, which allows the hollow braces and small x-sections seen in higher end bars *cough* cusco.

Anyone feel free to add to this, I'm learning alot.

I've basically started out unconciously making the assumption that the loads will be small relative to the yield strenth and that it'll resist buckling, in which case the Young's modulous is important and the yield strenth doesn't really matter because the column's not going to yield or buckle. Even assuming a load of say 250lbs, which is more than I'd think exists in the bar you'll find that using the curves gives you a very small cross sectional area, and radius of gyration, so much so that any bar ever made is sufficiently rigid to avoid buckling, in which case the strenth is irrelevant. This is backed up by experiance, even the flimsy eBay ones don't buckle or deflect much at all, backing up the low load assumption.

In any case, it won't take a big area and radius of gyration to push the design of the bar into the Euler area of the curve, meaning the strength of material is irrelevant.