What I'd like (Metal crafters, look)

[tehbrookzorz]

Oh... You know what? I didn't even think that it might be beneath the recesses of the speaker covers, because I'm not using my speaker covers. Haha.

[Ukrman]

found it for sale even cheaper

http://www.carparts.com/WHITELINE-QUICK ... _10618.car" onclick="window.open(this.href);return false;

[fowljesse]

Those are just converted bicycle seatpost clamp quick releases. I highly doubt that they would hold strong enough for your bars to work. That tiny bolt stretches, and the plastic camguide squishes. I've been an avid bicycle mechanic/ racer for many years. I tried using them for another application, and was surprised how little clamping power they had. If you were to notch your bar ends, and where they attatch, they could work.

[Ukrman]

Correct me if I'm wrong, but you don't need clamping power, its just to make it easier to take off.

Its not like on a bicycle where its not a complete circle and once you release it you can take the wheel off, here once you release I think you have to unscrew it all the way just like a regular bolt, you just won't need a wrench. At least thats my understanding.

[Ryan]

I don't think it needs clamping power either, just shear strength.

[fowljesse]

Of course it needs clamping power, otherwise, it doesn't work. That's why the OEM front is one solid piece. Otherwise, you have a bar two pivots, and the car flexes that same as it would if there wasn't anything there. Basically, the suspension is a "U", and the tops flex, making it less precise. The bar makes it a box, and when the top corners of the box are soild, they can't flex, making suspension response tight. If you put in a bar that's not tight, you have a flexing "U" with a bar on top.
I'm looking into making a soild rear strut bar, and braces that would connect my strut tops to the B pillars, for even less flex.

[Ryan]

Okay, question.

Strut bars try to compensate for movement between the towers, or at least transfering force. Is it when they lean both together, or both to one side? I would think both lean to the same side, so yeah, if there was even one pivot point, the bar does very little.

[fowljesse]

Yeah. The bar is there to try to keep them from leaning.

[tom_finn]

hauling really large loads like campers and stuff isnt meant for this car, you will lug the engine and it will be that much closer to the junk yard

[wytbishop]

Both towers do flex in the same direction, but the outside wheel has almost all of the load in a hard corner so that side would flex much more. The inside tower acts as an anchor for the outside. You cannot eliminate that flex and you don't really want to, the strut brace minimizes it. The total deflection we're talking about here is millimeters. A very strong pin (high strength in shear) is way more important than whether the brackets are rigid or pivot. If the brackets can't pivot and you really drive it hard, I bet you would eventually break the welds in the bracket.

Research will need to be done.

[Ryan]

Play with Fantastic Contraption. What happens to a bar trying to hold two points apart if there is a joint in it? It folds.

[tehbrookzorz]

Regardless, the design of my current strut bar includes 'pivots.' The bar also preloads. If the pin diameter is the same as the bolts that normally hold the bar to the feet, I am happy. In this case, I don't believe the clamping force has to be very strong, because there is minimal force along that axis. The shear force is important, because it is directly related to the strength of the bar.

[Ryan]

I completely agree with you, but I'm attempting to fully understand the physics. If there are 2 pivots in it, it simply bends slightly into a Z shape and does nothing.... but I think because its mounted solid to the strut top (4 bolts, not one swivel point) it does indeed work... Yeah.

Clamping power, not important. Shear strength, yes. The clamp isn't what resists the torsion, its the force running parallel to the bar.

[wytbishop]

So I'm full on involved into the question of what's going on with the strut bar. These are my thoughts so far...

Let's also say that 80% of that weight is on the outside wheel in a hard turn. That means that the frictional force the road exerts on the outside wheel is much greater than that of the inside wheel (because the frictional force is equal to the force acting straight down times the coefficient of friction). Since the frictional force is always directed opposite the direction of motion, it acts toward the center or apex of the corner. Since the weight of the car is acting away from the apex, a net positive moment or torque is created about the center of rotation which in this case is the ball joint if we're talking about the front or the Lateral Link outer ends on the rear.

Because the force due to friction is greater on the outside wheel, the moment about that ball joint is also greater and as a result the stress on the outer shock tower and subsequent deflection is greater. The inside tower does experience a stress, but not as great as the outer wheel so the net result is that the strut bar would be in tension.

That's why it doesn't matter if the bar is pinned at each end. It doesn't even matter if the bar is straight. The pins don't even have to be tight. As soon as the suspension loads up, the strut bar will become taught. The strut bar cannot buckle in the middle either, so a slight bend won't hamper performance (although too large a bend will allow too much "straightening", defeating the purpose). If the strut bar was perfectly straight from clamp to clamp it could be very thin. If a bend is introduced to clear the intake manifold the bar would have to be substantially thicker to resist flexing itself.

All that being said, I think it is far more likely that the strut itself is where the greatest flexion occurs. The shock is secured to the spindle/steering knuckle by two bolts...and it's a tall, fairly thin assembly. I bet in reality it flexes much more than the body of the car.

I think this is one of those things where it's obvious that there is something to be gained, but the gain would really be imperceptibly small. I'm still gonna build one though.

[Ryan]

[quote="wytbishop"]So I'm full on involved into the question of what's going on with the strut bar. These are my thoughts so far...

Because the force due to friction is greater on the outside wheel, the moment about that ball joint is also greater and as a result the stress on the outer shock tower and subsequent deflection is greater. The inside tower does experience a stress, but not as great as the outer wheel so the net result is that the strut bar would be in compresion. [\quote]



Now I completely agree with you
When it comes to pivots, because they are mounted solid to the towers(cannot rotate on any axis), one or two pivots would not change the strength, but I believe three pivot points would cause it to fold, defeating the purpose.