DoubleWhoosh

To help clear up the previous non factual opinions, impressions and statements, here are the facts:

Stock front bar, 28.5mm
TRD front bar, 31mm
DST front bar, 32mm

Stock rear bar, 14mm
TRD rear bar, 19.2mm
DST rear bar, 19mm

The front bar is pretty thin wall material, TRD is solid, DST is pretty thick wall material. Some slight changes were made with the DST front bar for better fitment purposes.

The rear bar is solid on the stock bar, and the TRD bar. The DST is hollow.

Assumptions (opinions) were made that the TRD rear bar was small, in reality it is quite large for this particular chassis. I do know for a fact exactly why the bar is this particular size, but that information is not relevant here. Basically, the TRD rear bar is quite large for this application, and the front is matched accordingly. These are pretty much the stiffest bars you can safely put on this vehicle and still make it driveable. This is also why it exceeds the comfort level for many users - the sizing is quite extreme.

On this chassis, the rear bar definitely does not control the front of the car and vice versa. If you tried every single combination of sway bars on the market, in combination with each other, (mix and match) along with no front and/or no rear bar, you'd be able to gather the data required to know the characteristic behavior of this chassis. I can guarantee that the rear TRD bar cannot be used with any other front bar. Don't even bother to try it - you will die. If anyone tells you otherwise, run (not walk) away from them..

Now, back to the earlier point that a hollow sway bar only loses a certain percentage of stiffness over a similar OD solid bar, you can start to see some sort of logical structure among the above mentioned sizes. The wall thickness is quite critical with hollow bars, but short of going into another tangent topic, a pretty thick walled hollow bar will be pretty damn close to a solid same OD bar, and will be a significant upgrade over a hollow thin walled bar. As I had said earlier, in a nutshell the stiffness comes from the OD more than any other factor.

On a final note, this particular chassis is extremely sensitive to sway bar sizing. Not in an overall stiffness sense, but in a chassis-balancing sense. The overall stiffness is not as significant as is the overall balance.

Before anyone out there gets any bright ideas about mixing front and rear bars, DON'T EVEN BOTHER! Trust me, it won't be worth your time, as there will be either no gain (actually a loss in performance), or an extremely dangerous handling vehicle. Just stick with the matched front and rear set of whatever brand (or stock for that matter) sway bars.

I think this is all pretty objective information without promoting one brand or another. If you wish to argue any of this, first go ahead and test everything. I have a lot more data on this, but of course a lot of it is for our own use and I would prefer not to share it. I am pretty confident however that anyone else will have the same conclusions.

DaveGS4

iTrader: (2)

Great info Todd, thanks much!

Couple of additional items I'd like to see that I can't find after reading all the stuff above if you or anyone that has had access to the various sways.

What are the comparative weights of the three bars front and rear?

I've read in other posts about unsprung weight being a factor with the DSTs.... Aren't sway bars attached to the chassis at a point where they'd be considered part of the normal load of the car (sprung weight)?

I'm very interested in learning about these new options for GS owners. At this point I don't plan to switch out my TRD Race sways; I'm perfectly happy and have absolutely no complaints on ride quality or stiffness issues with them. BUT I think it's great that folks making an initial purchase have more options.

DoubleWhoosh

Oh yes, we've tried them all, including mixing and matching. This why I don't suggest mixing and matching...it's definitely not a smart thing to do, you will surely die. Don't ask me why I know this

I haven't done any exact weight comparisons, I'll probably get around to that sooner or later. We just don't have a scale with any resolution smaller than .5 lbs. I suppose that would be enough for a comparison like this.

On the unsprung weight, the lever arms of a sway bar are basically 1/2 of their weight in unsprung weight if I recall correctly. Unsprung weight does have a severe impact on handing, etc. even a few pounds.

rominl

iTrader: (4)

this thread is so technical and so much information about sways bars, and i love the fact that it's staying very neutral about pure facts and information, and no saying this good and that bad. i think i will make it a sticky (just like the coilover thread) so people can learn more about sways

and i will reserve my opinions until i try out the sways this weekend. i am going to make an extensive testing and put up my reviews. i have already did some prelim testing, we will see

DrewGS4

Great post everyone and excellent information

I am also very happy with the TRD race sways. If the poly bushings are available for the TRD sways that is one direction I might go vs my rubber bushings.

The only other reason I would switch is the weight factor advantage of the Daizen. For first time buyers at least now there is an option. Would like to know the exact weight diffence.

Mr Johnson

Great post!

DoubleWhoosh

Well there really isn't any less body roll than the TRD...that is everyone's point that has tried them. They perform pretty much the same. Until you try them you cannot dispute this or make comments on it.

The point is, that if you switched from the TRD to the DST or stock, you WILL notice a difference in ride stiffness...and it is substantial. This is not whether you object to it or not, the purpose of this post is to compare them. If someone doesn't think there is a difference, then they are probably oblivious to many other things as well.

Bliu and rominl are not perceptive enough to compare these? I think not. If you say there is no difference between stock and the TRD bars as far as stiffness, I'm sure they will beg to differ. I am going out on a limb, but I think they would think you are insulting their intelligence if you said there was no difference. This is the type of info this thread is trying to uncover. I'm sure as more people try these, they will have the same conclusions. Neo is on the fence since he changed his springs and shocks as well, but I'm sure he'd put a decent wager up that the TRD are considerably stiffer of a ride than the stock sway bars. Any of these guys would also concur that there was NO loss in roll stiffness or handling. Bliu was the blind test guinea pig for most of this, ask him.

If you need input on the ride stiffness difference from stock to the DST, ask Kajukenbo, ask lexforlife, wineohs, gs300rich, phml. I am sure they will tell you the same thing, there is no significant change in ride stiffness.

Neo

iTrader: (3)

I think this is one of the major factors plus each of us has different suspension configurations. Ron430 is running a "minimal" configuration that works great for him. I don't dispute that.

I went to 18s and braces galore. They all contributed somewhat to the ride handling and quality. Maybe I should have swapped out the L-Tuned for the Flex first before the sways to get a better idea of the changes but it was just not convenient to do so. I am somewhat happy now with both handling and quality. I just need to play with the Flex settings some more. I will try some tests this weekend. The only reason why I am not as excited about the DSTs is the Flex. I cannot in all honesty say which contributed more to the ride quality improvement. (I am running the Flex at softest right now.) BUT if I had to pick whether or not the TRDs produced a stiffer ride, I would say yes.

I never really had a problem with the TRDs on relatively good, flat roads. It is only on uneven roads that I felt the side-to-side effects of the TRDs. I am not going to say that I don't feel that now with the DSTs but it is significantly reduced. Maybe the stock bars would feel this way too. Sorry, I am not about to put the stock bars back on to prove this point.

With my "Flex caveat" in place, I did notice one thing though. With the ride being softer, the road feel is more muted. I don't feel as connected to the car as I did with my previous setup. I'll get back to this once I have more time to experiment with the Flex.

I may be on the fence like DoubleWhoosh said but if I lean a bit, I'd fall onto the DST side. If some of you have a set up that you are happy with, no one (including me) is trying to convince you to switch. Why would you? If the ones with TRDs feel like they would like to get back closer to the Lexus soft ride without losing the handling improvements, you might give the DSTs a try if budget allows.

The hard part is for people without sways. There is a choice now. Enjoy the choice. At the same price point, you're going to have to figure out what you want. Do you want the red DSTs to match your Tom's braces or ...

bitkahuna

iTrader: (20)

I understand your point.

[quote]Now what data do you have to back up that you are so convinced that they do not have the same handling between the two bars?[quote]

No 'data'. Happy? But one is called a RACING sway bar and the other was described here as for the "true" and "real" driving experience or some such subjective nonsense.

OK, I'll just accept the data you won't make public then. Very objective.

OK, so NO ONE should post here except those who have tried both bars and not made ANY other changes and have used instrumentation.

///MDex

VERY well said Neo Again, I want to thank everyone for their participation in this most excellent thread. Much good data has been assembled.

///MDex

OK guys. I think we have all the facts posted, with a healthy dose of opinion tossed in as well. It's getting alittle too personal

I'll likely CLOSE this thread later today.

rominl

iTrader: (4)

\

dex, i am going to post up my review later today or tomorrow, please wait a bit longer

RON430

I'll go back and read the other posts later but here is the data I said I would collect. Diameters were measured in inches on a dial indicating vernier caliper (accuracy listed at .001 inch) are measured outboard of the bushing locator on the front and under the middle of the bushing on the rear. I took measurements left and right and averaged

Stock Front Bar

1.128 to 1.129 OD 28.66mm

Stock Rear Bar

.558 to .559 OD 14.19mm

TRD Blue Front Bar

1.228 to 1.229 31.20mm

TRD Blue Rear Bar

.759 to .760 19.29mm

As for the weights

Stock Front Bar 8lbs 4 ozs

Stock Rear Bar 2lbs 6 ozs

TRD Blue Front Bar 18lbs 2 ozs

TRD Blue Rear Bar 2lbs 4 ozs

I caution trying to read too much into the weights as far as stiffness is concerned. Obviously, TRD increased the diameter of the rear bar but not the weight. Increasing the diameter increases the stiffness considerably. We also don't know if they changed any of the alloys of the steels which could also have a big effect. The weight increase of the front bar wasn't a big surprise but the rear bar did surprise me as the TRD bar in your hands feels considerably stiffer than the stock unit. Don't want to overstate anything but it appears TRD did some homework on these. In case you are interested, the hole in the bushings for the front TRD bar is 1.201 inch in diameter and the rear bar bushing is .732 inch in diameter so they obviously are slightly undersize to preload the bushing. For disclosure, the stock bars are the ones that came off my 2k1 GS430 (at about 2k miles) and the TRD blues are the ones waiting to go on my wife's GS 3.

RON430

Dex, if you want to close this thread, that is certainly your call. I do have problems with some of what has been posted here, either represented as informed or not. There are quite a few other comments you can make but I am trying to help some people who may not have a great degree of mechanical engineering training or experience. Besides measuring and weighing stabilizer bars (I need a life) I have also tried to find some references that may provide some more input. In Paul Haney's "The Racing and High Performance Tire" (co published by TV Motorsports and the Society of Automotive Engineers, 2003) is the following passage. It is a little long but I would like to put it in verbatim (I'll put in the carriage returns as printed bit):

"In a turn, inertial forces roll the body and also transfer weight from the inside tires to the outside tires. An ARB (Anit Roll Bar - RON430) adds to the total roll stiffness of the car, reducing the roll angle. But that roll stiffness comes at the expense of increased weight transfer at the end of the car, and that tire pair loses some grip. At the same time the other tire pair are more equally loaded and they gain grip. For a front ARB, the front tire pair loses grip and the rear pair gain, so this is an adjustment toward understeer and away from oversteer.

Twenty years ago I read a quote in a magazine that realy stuck with me, although I didn't understand it until much later. A racer said he's never seen a front ARB that was too stiff. He drove a Camaro, a heavy, powerful, rear-wheel drive car. That stiff ARB helped cure power oversteer at corner exit. He could somehow get it to turn into the corner even though it wanted to understeer, but he could really get into the throttle coming out of the corner. The hidden power of the ARB is wedge at corner exit.

With an ARB the price you pay for some extra roll stiffness is increased load transfer and less grip from that pair of tires. If the ARB is added to an independent suspension that system is less independent with the ARB. The wheels are linked to some extent when the ARB is in use. But an ARB lets you have more roll stiffness with softer ride - spring rates and less damping, which might provide more grip overall. It's a trade-off, and testing might be the only way to make a choice."

pp. 265-266.

In the sixties, we barely had front ARBs. You always added a rear bar first and then increased the size of the front bar. And, as stated above, you will see more grip at the opposite wheel pair than the one you are increasing roll stiffness with. I knew from the get go that I was willing to live with the contact patch, and wall stiffness, of the 16s and had no interest in either lowering or increasing spring rate. The bilstein sports made a significant improvement in the handling I was looking for but I wanted more roll stiffness. While increasing ARB stiffness can increase ride harshness, it is only in the situation where one side of the car is experiencing something the other side is not. If you encounter a bump with both the left and right wheels simultaneously, the ARB is a non player in anything to do with ride or handling. But, once again, the whole suspension must be viewed as an entire system and one that ultimately is being adjusted for an organic response, your buttometer. The more you know, the better choices you can make in tuning a suspension. Knowledge and choice in components are our best weapons.

///MDex

I discussed this with Dave earlier today. What I'm going to do is this:

SPLIT this thread into two threads - one with products facts and data only, the other as a "Review & Debate" on the DST & TRD Sways



For the continuation of this thread, PRODUCT FACTS ONLY PLEASE

Your experience, and ".02", please post HERE

Thanks everybody