matt777

As I wait for my extra PSS10 locknuts to arrive and further tool delays (no 7mm allen key in my 2 sets!) , I have too much time to wonder about my sway bar selection and whether these fat 24/26mm bars will work for me or not. It is primarily a street car but not a daily driver. There seems to be mixed opinions on these H&Rs although I can't find a post where somebody actually took them off. A couple of people liked them. After taking off my old bars I see that they are very similar physically except for the diameter. Yeah I know...according to the calcs they are twice as stiff as stock bars. There are 2 sets of holes so you can go to an even stiffer setting if you want. I suppose I will try them now I have gone this far. What is the risk if they are in fact too stiff?

ps I thought I would struggle getting the front sway bar bushing mounts off but they easily popped out using a punch from under the car. Too easy. Perhaps the struggle will be getting them back in.

VMXWinn

I just put on Bilstein HD's along with H&R sway bars, my car's PO had installed H&R sport springs, and yes the ride got alot frimer do almost all to the shocks. I have the swaybars both set at their softest setting and I think it feels pretty good now. I have not yet had a chance to take it to the canyons but we have a big drive planned for in a couple of weeks and I will report back then.

Martin S.

Sway Bar Calculations

Provided by KLA Industries
Here is the angle of the dangle formula for calculating the change in sway bar stiffness. For ...a change in bar size you would use the formula below. If you're substituting a larger diameter bar that otherwise has the same dimensions, the rate increase is simply:

(new diameter/old diameter) to fourth power

So when you change your bar from 18mm to 19mm, the stiffness increased 24%. (19/18)^4 = 1.24

TEST 18 Increase in Stiffness
19 1.06 1.11 1.18 1.24 24% {The calculation in the article}

REAR 20
26 1.30 1.69 2.20 2.86 86% {Set up in EXCEL to duplicate the test}

FRONT 17
24 1.41 1.99 2.81 3.97 97% { " " " " " " " " " " " " "}

Bottom line, those 26 and 24mm bars are Monster compared to stock. Consider that the 993 RS runs 23mm front bars and 20mm rear bars.

Of course I could be completely wrong on this....but maybe I'm right??

matt777

That's good to hear. Please let me know what you think after some spirited driving. I'm hoping that the upgraded Bilsteins will work well with them.

Yes, I did figure out that they were nearly double the stiffness. The fact that the upgraded Porsche bars are not as large was what raised the question. Were the larger Porsche sway bars specifically designed for Bilstein adjustable shocks/struts? I could see how large sways might not work with a stock shock/strut. How much extra force do larger bars exert anyway and what is the result? I guess I will find out soon enough Looking at the size of the droplinks I would say the transmitted force is relatively low but I have no experience with high performance suspensions. Worst case scenario, I have to buy another set of bars. Hopefully I will only have to do a bit of tuning.

TheOtherEric

I'd calculate the stiffness on their softest setting... if it's close to stock, great. (start by just comparing the "lever arm" lengths). But if it's twice as stiff as stock on the softest setting, then I wouldn't even consider putting these monster bars on a street car. Not for a moment.

Remember that sways bars are the enemy of independant suspension. A bump felt on one side is transmitted to the other side. The stiffer they are, the worse that gets, and it does degrade ride quality. Under heavy cornering they also cause weight to transfer to the outside wheels, which is not always idea. So why run thicker sway bars? Because it causes the car to corner flatter, which preserves suspension geometry and thus cornering g capability. Why do you feel your car needs to corner flatter? IMHO stock bars work fine for all but track duty.

matt777

They are almost twice as stiff on the soft setting if you look at diameters. The lever lengths are the same. There doesn't seem to many H&R sway bar users so feedback is minimal. VMXWinn hasn't complained about a harsh ride yet. We'll see. I'm not worried, just a little confused as the theory doesn't seem to jive with the real world experiences. Is the magnitude of the force exerted by the sways really high enough to adversely affect grip during performance driving or in the rain? Now I am really over my head. Interestingly enough, I haven't seen any published ratings on sway bars. I am sure there is a limit to sway bar diameters but...

TheOtherEric

Then I wouldn't recommend them except hardcore track use.
They're about the same (exactly?) as TRG bars and there's tons of feedback from TRG users. Some like TRG and others find them too large. I ran TRG for a few years of largely track duty, yet I still found them too large (I replaced them with smaller RS). I prefer a little more roll (it's funner, plus the roll is useful driver feedback). Plus I chose to deal with roll via stiffer springs instead of sways (kind of a "Lotus" mentality; deal with roll properly; via springs, not sway bars. Or just let the car roll and have fun with it.)
These bars will improve lateral grip in the dry; that's why race teams (TRG!) run them. But for street driving, so what?? So you can corner at 0.93 g's instead of 0.90; there's little use for that, and hopefully you're not normally driving that hard on the streets! And these bars will hurt grip in the wet; some guys unhook sways for wet races.

But if you're not too sensitive to ride quality, it may make little difference to you. I'm kind of **** about it, that's all.

matt777

Thanks Eric. I guess I will find out first hand. The H&Rs were an impulse buy because that is what the Bilstein dealer was selling. It will be awhile before I can test them as it's -30C today so it's not likely that the roads will be suitable until well into April. I can always unhook them temporarily to see how much affect they have. Perhaps if a used set of M030's comes up for sale in short order I will make a change now before I put things back together. I hate it when things aren't right on the car.

Martin S.

The TRG bars are too damn gig in my experience. I have to run the 25mm front full soft or else, I'll start lifting an inside wheel. It is nearly always better to drive with 4 tires on the ground in contrast to 3.

On the 3 position back (22mm) bar, I run high speed tracks on full soft, technical tracks where I want to rotate the car, on full stiff....medium scary tracks, in the middle on the rear.

The Fred Puhn book "How to make your car handle" is the bible on sway bars...the calculations for stiffness using adjustable bars is over my head.

When "your ship comes in", get a set of 993 RS 23mm front and 20 mm rear bars..$1,500, maybe more.

Mark in Baltimore

I agree with a lot of what Eric and Martin said. I think my TRG's are too big for my set up, especially in the rear (rear bar is set to the softest setting). I'd love to have more adjustability with a smaller bar. That said, I do think my car is set up very, very well, so I have no desire to monkey with a terrific platform.

I can't imagine what the H&R's would be like. I did get a chance to drive a Sam N's G class 993 race car last summer (JRZ's and H&R's). Although I only drove 7-8/10ths, the car felt fine to me, if a bit sloppy in the rear.

Martin S.

I had M030 (RoW) fronts, 22mm and 993TT RoW rears, 21mm with an added hole for additional stiffness if needed. Used stock drop links too.

With my impulse buy TRGs (They were 1/2 the cost of the 993RS bars), I use Tarett drop links...never a problem since I went to Tarrett.

Recall, "old school", torsion bar cars, they'd tune their suspensions with sway bars...with modern suspension, springs are the key...so they say.

matt777

Sounds like the H&Rs might be okay? I'll definitely report back once spring arrives and I can get it to the shop for an alignment and corner balancing. I have 30 years of driving experience but no performance driving experience unless you count dealing with back end of a Mopar sliding around under full throttle. That will change this summer.

Mark in Baltimore

I didn't really push the car as hard as I would pushed mine. At the speed I drove it, the suspension felt pretty good. However, Sam is, ah, very casual about his car set up and has not really tried to tweak things to the nth degree, so I still think that there's a good chance that the bars are too big for proper set up.

matt777

If it's only going to be an issue at the upper limits i.e. high speed cornering it will probably be along time before I can push the car that hard. We have no track here although there are autocross type events out at one of the airports. There are some rumblings about building a track but that has got to be a couple of years away at minimum.

jungleboy

Matt,
Keep us posted please... I am planning on a similar setup if anything for the money savings over the RS bars.

Arun