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Old 07-08-2007, 05:51 PM
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Default Big enough/light enough sway bars?

Spohn 32mm front (solid) & 22mm rear (solid) 4140 chrome moly sway bars strong enough/light enough? Anybody know the weight difference from the stock bars? I'm looking at ordering from lighted than stock sway bars from Spohn tonight or tomorrow.

Looked around, but, the search feature doesn't nail any up-to-date Spohn products ... brings up **** from 2003 and back.

Any advice/answer is appreciated.

Last edited by JEB99TA; 07-08-2007 at 06:18 PM. Reason: Change title
Old 07-09-2007, 01:58 PM
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No, the front is not big enough, and they aren't "light" bars in any way, shape or form.

CM isn't magically lighter. CM parts tend to be lighter than mild steel when the parts are tubular and the greater tensile strength of CM allows the use of a thinner wall tubing. If you use solid stock, there is no weight difference, and actually CM is a more brittle material when flexing is involved--which swaybars do a lot of.

And while the rear bar is a decent size, the front bar is relatively too small IMHO. If we use a 32mm front, I stay with a 19mm rear. If we use a moderate rear like a 21 or 22, we use a larger front. My bars are 35/22, and both are hollow. Meaning you gain very little weight (about 2 lbs) up front, since the GM bars in front are hollow, and you save about 5-6 on the rear vs. the stock 19mm solid. Comparing my bars to solid 32/22's, the difference between the pair is about 15 pounds, and compared to solid 35/22's it's about 20.

Bottom line is only hollow bar sets (front and rear) save you weight vs. stock.
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Old 07-09-2007, 02:05 PM
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hey jack deff go with sams setup you wont be disapointed i have them and love them. and when r u getting your hood painted i can have it done for about 350 if its dosnt need much prep.
Old 07-09-2007, 02:10 PM
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so which is better solid or hollow
sorry
Old 07-09-2007, 02:13 PM
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i would say the hollow b/c it allows for more flexing in a corner and that would cause it to absorb a little more of the road causing the tires to stick better to the ground.
Old 07-09-2007, 02:18 PM
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You want bars to give you an amount of roll stiffness. Hollow vs. solid doesn't matter in that regard because you just alter the size of the bar and in the case of hollow bars the thickness of the wall size in the tubing. You will NEVER see solid bars on any kind of serious competition car, it's just dead weight, and in the rear of this car isn't worse because that dead weight is also unsprung weight--a double whammy.
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Old 07-09-2007, 02:20 PM
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thnks
Old 07-09-2007, 09:30 PM
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Alot of dual purpose cars (street/road race) running the hollow Strano bars on here(mine included).
Its a proven combo, and there just isn't a downside to being lighter.
Sam is an experienced and successful auto-xer. He picks his spring rates and sway bar sizes after much thaught and experience. Thats why he has the respect he does on here.
I really couldn't be happier w the combo I have from him (koni SAs, Strano Springs and 35/22 Sway bars). It not only feels better on the street (subjective), it has reduced my lap times (objective).
Old 07-10-2007, 05:16 AM
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So, I guess I'm down to sort of a different question after reading the replies here. here are 2 questions maybe someone can answer for me:

1. How much better than stock is a solid 32mm chrome moly front swaybar ... for street/strip useage?

2. The primary purpose of the front sway bar is to keep the tires flat as possible by disallowing as much body roll as possible when rolling into a turn really hard, right? It seems sensible to me that a 32mm solid single-coined/chrome moly heat-formed front sway bar would achieve this purpose better than a cold-formed hollow bar being 35mm size difference ... 3mm is hardly any difference at all, so, why would the weaker hollow bar be so much better than the solid chrome moly bar? I would think the opposite would be true.
Old 07-10-2007, 08:34 AM
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Originally Posted by JEB99TA
It seems sensible to me that a 32mm solid single-coined/chrome moly heat-formed front sway bar would achieve this purpose better than a cold-formed hollow bar being 35mm size difference ... 3mm is hardly any difference at all, so, why would the weaker hollow bar be so much better than the solid chrome moly bar? I would think the opposite would be true.
Nope. That 3mm of diameter is very significant. It's all about the math. Bust out the calculator and see for yourself.

Most of a bar's resistance to twisting is in the outer region of the tube. That is why a hollow bar of decent wall thickness can be nearly as stiff as a solid bar. That is why a larger diameter bar is much stiffer than a slightly smaller bar.

I don't have Sam's bar so don't think I'm patting myself on the back here. He didn't have them out when I bought my solid 35.
Old 07-10-2007, 01:51 PM
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A hollow 35 is stiffer than a solid 32. And a solid 32 is a waste of money to go with, unless of course you like spending money on parts that are little different functionally and weigh more too.
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Old 07-10-2007, 06:20 PM
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If you're going to spend money on a 32mm solid, you might as well try to find a deal on a 1LE bar somewhere. Either go 35mm hollow or 1LE bar. The 1LE bar won't be all that noticeable though. I'm very happy with my 35mm hollow. I matched it with a 21mm solid SLP piece that I picked up for $50 brand new from someone local. I'm very happy with the feel. I am debating picking up Sam's 22mm hollow in order to save a few pounds out back of unsprung weight. I'd like to take away some of the "heavy" feeling back there with the 9" and 17s.
Old 07-11-2007, 12:13 PM
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The catch is that while everyone thinks 32/21 is a standard "1LE" configuration, and it was, it was only for one year--the first year. And that car did not use 1LE rear springs, but stock Z28 rear springs either. Every other GM build 1LE had 32/19, and SLP built ones has 35/21's.

In short, 32/21 is too rear roll stiffness biased when compared to the front IMO.
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Old 07-11-2007, 01:20 PM
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I concur... had 32/21 1LE on stock springs and it was doable, but the 35mm hollow up front is better when paired with good shocks. More stable, a little more understeer when you enter a corner too fast, but that is ok. Better off the corner when on the gas.
Old 07-11-2007, 08:11 PM
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... good info guys. Thnx ... mine being adaily driver, I think I'll go with the 32mm solid single-coined, heat-formed, chrome moly bar because my street time is nearly 100% and my needs are to have something just a little better than stock. If I were a auto-x racer, after hearing you folks opinions, I'd definitely go for the hollow 35mm bar. I believe I'll go with the hollow bar on the rear ... simply because of the power level I intend to achieve and the 12-bolt under the car and I will be drag racing more often, as sell.
Old 07-11-2007, 09:27 PM
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JEB, Did you already buy these or something?
Its your car and if you want to go against what everyone else has said, no problem-->its your car.
But it really seems you will be making your car heavier (and your wallet lighter), w no real advantage.
Especially if you drag race, the last thing you want is more weight(especially up front). Heck, alot of drag racers take off the front sway bar all together to shed front end weight.
And if you want good handling on the street, but don't need it to win an autocross, the stock bars will do quite nicely.
But, again, do as you wish. Not trying to agrue, only summarizing the thread (as I see it).
Old 07-11-2007, 11:28 PM
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Go with the Strano bars. Or if you want to spend more cash then go with the Hotchkis 36.5 mm front and combine it with a 22 mm rear. Strano could make this happen for you also.
Old 07-12-2007, 05:44 AM
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How much does the hollow 35mm bar weigh? With a 35mm size and 6mm wall thickness, it can't be much lighter than the solid 32mm chrome moly bar IMO (27 lbs), which is lighter than the stock hollow bar from the factory. Isn't that the same weight as the 35mm Strano hollow bar? Looking at some level of comfort here, as well. As I had stated, I just wanted a little something more than the stock bar ... especially after reading some posts here that the 35mm bar is waaaaay too stiff for a daily driven mostly car (from people who had a 35mm hollow bar and changed because it was too stiff).

The HD Bilstein's are already pretty stiff and the subframes have me launching pretty solid. I want a certain level of comfort as a daily driver, since it will only see the dragstrip 2-3 times per year. For my personal needs, I believe the 32mm solid chrome moly bar will be perfect. They're not expensive, so, I just ordered one for the front. I'll be doing the Strano bar for the rear for sure. If the 32mm bar feels good up front, then, that's what I'll ... if not, I'll order the hollow Strano bar. Besides, when I go to the track, I'm taking the front sway bar off, anyway. Thanks for taking the time to reply to everyone who did. I'm open for more comments.
Old 07-12-2007, 06:00 AM
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The stiffness of the swaybar is proportional to the diameter raised to the 4th power (D^4). For a hollow bar, that's ((OD^4)-(ID^4)). Actually, the second version covers all cases, but the ID is zero on a solid bar

Note that (OD^4) is going to be a MUCH bigger and more important number than (ID^4).
Old 07-12-2007, 07:43 AM
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Originally Posted by JEB99TA
How much does the hollow 35mm bar weigh? With a 35mm size and 6mm wall thickness, it can't be much lighter than the solid 32mm chrome moly bar IMO (27 lbs), which is lighter than the stock hollow bar from the factory. Isn't that the same weight as the 35mm Strano hollow bar? Looking at some level of comfort here, as well. As I had stated, I just wanted a little something more than the stock bar ... especially after reading some posts here that the 35mm bar is waaaaay too stiff for a daily driven mostly car (from people who had a 35mm hollow bar and changed because it was too stiff).
I have my strano bar sitting here and I just put it on scale, ~15lbs. Im probably going to install it today after work, Ill let you know how much rougher the ride is after.


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