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Registered:
August 2002
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Strut Bars Front/Rear: Myths and Facts
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Sun, 27 April 2003 23:26
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Ive been doing some research into the theory of the strut brace in front of a car but havent found too much on the rear.
Now ive read that there is both contraction and expansion forces exerted upon the bar during different cornering situations.
I own a 1984 Supra and plan on doing an engine upgrade (quite possibly 7m) soon and the suspension is not really up to task.
Just wanting to know if the strut tower bar is purely a ricer cosmetic feature or a proven suspension tool?
Will it only be useful on a track car vs a street car?
Will a rear strut tower bar affect the dynamics of the IRS?
And if i go front strut tower bar, will it vastly the affect the rear end if i dont put a rear strut tower bar on it?
And what do you think of this little beauty?
http://ca.photos.yahoo.com/bc/farmz1ca/lst?.dir=/M KII+Supra+triangulated+strut+bar&.src=ph&. order=&.view=t&.done=http%3a//photos.yahoo .com/
Sorry about all the questions, just trying to determine myths and facts.
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Location:
Brisbane
Registered:
May 2002
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Re: Strut Bars Front/Rear: Myths and Facts
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Sun, 27 April 2003 23:56
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The purpose of a strut bar is to prevent unwanted changes in suspension geometry as a result of body flex. A front strut bar on a McPherson strut setup is always useful, even on a road car; however its effectiveness depends on how hard you push your car and how stiff the body shell is to begin with.
As for a rear strut bar, I can't see the point of such a thing on your car because the strut towers simply house the shocks, which are not used for wheel location. In other words, rigidly locating the shocks will have little or no effect on suspension geometry.
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Location:
The Rainy City
Registered:
May 2002
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Re: Strut Bars Front/Rear: Myths and Facts
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Sun, 27 April 2003 23:57
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Im not sure about theories and racing practices, but ive recently installed a front strut brace into my starion, and it is doing wonders. Turn in is improved, though some may call it twitchy cos ive got it adjusted up pretty hard.
My only real worry is that ive heard that overtensioned strut braces can crack the chassis... any opinions on this?
cheers
tom
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Registered:
August 2002
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Re: Strut Bars Front/Rear: Myths and Facts
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Mon, 28 April 2003 00:18
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Well those yanks with their MKII's seem to swear by both front and rear bars and beleive both make vast improvements.
Im just wondering if you hit a point whereby your car has so little body flex that you start lifting wheels through corners if you brace it in such a fashion.
And what do people think about the difference between the straight strut bar and the one that bolts to the firewall?
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Location:
sydney,nsw.oz.
Registered:
July 2002
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 Re: Strut Bars Front/Rear: Myths and Facts
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Mon, 28 April 2003 03:36
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Hi Mr.Black Supra,
ST162 Celica (FWD) came out in late 1985 with a Front Strut Bar standard. It is attached to the Firewall. Pipe is about 4cm diameter.
This was before the term "Rice" was even thought of. Whether they work or not is hard to say. But the ST162 is widely thought of as 1 of the best handling FWDs even today.
They must do something or Toyota wouldn't have wasted the money putting them on.
My 2 cents worth.
Cheers
T.
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Location:
Brisbane
Registered:
May 2002
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Re: Strut Bars Front/Rear: Myths and Facts
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Mon, 28 April 2003 03:48
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| BlackSupra wrote on Mon, 28 April 2003 10:18 |
Well those yanks with their MKII's seem to swear by both front and rear bars and beleive both make vast improvements.
Im just wondering if you hit a point whereby your car has so little body flex that you start lifting wheels through corners if you brace it in such a fashion.
And what do people think about the difference between the straight strut bar and the one that bolts to the firewall?
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Well you know what the Yanks are like... if it's shiny and has a brand-name sticker on it, it MUST be good!
Ideally there should be no body flex whatsoever; all of the compliance should be in the suspension. If you start lifting wheels it's because your suspension is too stiff, not because your body is too stiff! Have a look at all the cross-bracing they put in WRC cars, V8 Supercars, etc. They wouldn't put all that extra weight in there if it wasn't doing something!
Triangulated strut bars are a good thing because they locate the struts longtitudinally as well as laterally. If you have room to fit one, go for it!
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Toymods Board Member
I supported Toymods
Location:
Turramurra, Sydney.
Registered:
May 2002
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Re: Strut Bars Front/Rear: Myths and Facts
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Mon, 28 April 2003 09:04
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Yeah, strut braces are definitely a good thing.
I was very impressed with the improvement one made on my car, heaps better turn in on slower corners, & the front sits so much firmer on faster corners, I would hate to have to take it off & drive without it.
One thing about strut braces though, they are NOT meant to be adjusted once on the car! The adjustment is only to fit it, which should also be done on a flat surface, and then locked in that position with the nuts supplied.
Preloading tension or compression forces on it would certainly risk damaging the strut brace, & I guess cracking the chassis wouldn't suprise me either.
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I supported Toymods
Location:
melbourne
Registered:
June 2002
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Re: Strut Bars Front/Rear: Myths and Facts
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Mon, 28 April 2003 09:33
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nothing wrong with lifting a wheel off the road, as long as it isn't a driving wheel. its not giving you any traction, so why have it on the road??
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Location:
Hobart, Tas
Registered:
May 2002
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Re: Strut Bars Front/Rear: Myths and Facts
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Mon, 28 April 2003 14:45
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FWIW I think I read somewhere that a strut bar helps the most of strut-type designs (makes sense) but can still help other designs, or that the most improvement will be with strut-type designs. I know that's not lending much to the conversation, but it makes sense.
I thought the Alpha Sprint was supposed to be one of the best handling fwds. I read this great book.... "Handling and Roadholding" by some car engineer, and the sprint was one of the few listed 'good' fwds at the time that handled a lot like a rwd.
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Location:
Madrid - Spain
Registered:
August 2002
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Re: Strut Bars Front/Rear: Myths and Facts
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Tue, 29 April 2003 03:28
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One of the biggest problems with desiging a car chassis is maintaining adequate stiffness. Usually this is a trade off between cost and performance and you can guess where the trade is pushed.
The idea of a strut brace is to increase the chassis stiffness where the load carrying suspension points are. The idea being that the suspension cannot do it's job properly when it's mounting points are moving about. As norbie said, a macpherson strut will benifit from a strut brace as the strut is responsible for locating the upper half of the suspension. Live axel, double wishbone, 5-link etc set ups probably won't benifit from a strut brace because the towers are not locating the suspension components, only the shocks.
As far as fore/aft members on a strut brace are concerned, most of these loads will be taken by the lower control arms / wishbones. The proportion of this load of course depends on the suspension geometry, but I doubt you would see much of a difference.
What I find interesting is that a lot of these strut braces are bent, which means that they have to be made a lot heavier to maintain the same stiffness as a straight bar. All this weight is carried very high in the chassis, loading up the suspension more in a corner. I guess some have to be bent to get around the engine without fouling on the bonnet, however I have seen plenty that are bent for no reason but to look good. I guess it is a good place to put a company sticker 
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