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H&R Sway Bars Settings

Discussion in 'E30 (1984-1993)' started by granthr, Jan 16, 2009.

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    granthr

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    I have just purchased H&R sway bars for my 1984 318i. The car already has H&R sport springs and Bilstein Sport Shocks/stuts. I am running 15in BBS rims with 205/55-15 tires. I bought all new hard ware for the install including new oem links. These bars are 22mm front and 18mm rear.

    Two questions.

    1st. What settings should I set these sway bars to. I want neutral handling and not concerned about ride comfort. The car is just used on the street right now, but I would like to do a DE in the future with it.

    2nd. I was thinking of just setting everything at the stiffest setting, but has anyone had issues with the tabs on the rear trailing arms where the sway bar links connect? In other words, has anyone had damage or stress cracks from running larger than factory sway bars due to the increased forces? I know there are aftermarket re-enforcements for these tabs, but they need to be wielded in. So at this point I would rather not do that.

    Thanks for any freed back or personal experiences.

    I know it is a 318i, but it has 325 brakes all around and only 75k on the clock. It will get a bigger 4 hole motor at some point.
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    MGarrison

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    I replied to that in Botond's suspension thread, but, in case you missed it :p

    I'm not sure if the rear bar setting would radically change when the rear tabs might start to tear. In any case, I doubt they'd start to go really quickly - if you don't want to do reinforcements at the moment, I'd think that's fine, and you can just keep an eye on them over time.

    I don't have experience w/ H&R's, but, unless someone else who has them offers up a suggestion, I'd think the conservative approach would be to approach the full-stiffness settings gradually. Just thinking that if their stiffest settings might make the car tail-happy, that could stand a chance to catch you out unexpectedly. Personally, I'd probably hold the new ones up to the stock ones and pick the holes closest to stock for starters, or maybe the front bar one setting stiffer than whatever's closest to stock.
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    Brian A

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    Good question! I wonder the same thing.

    I've installed the Eibach 20mm/16mm adjustable swaybars kit in both my 1987 325ic and my 1991 318i.

    I've did the 325ic about 4 years ago or so and, for lack of any guidance, just put the bars at the "middle" setting both front and back. I discovered it felt pretty good and have never changed the settings. Factory-tuned understeer is substantially reduced. Change in body roll is substantially reduced (the 325ic has factory springs, Bilstein HD shocks and an open differential). The car has a wonderful balance. Out of intellectual curiosity, I wonder what soft/soft or stiff/stiff would be like.

    I just did the 318i a couple of weeks ago (along with Dinan Stage 1 suspension). I figured (guessed) the car would be harder to oversteer since it has a LSD and less power, so decided to try to dial in a bit more oversteer. However, I erroneously set the bars for more understeer. I set the front to stiff and the rear to medium. (Stiffen front for more understeer; stiffen rear for more oversteer) (SOMEBODY ELSE CORROBORATE THIS). It's too early to say definitively, but the surprise is that 318i seems to be handling just fine as-is. This could mean two things; 1.) I am a lout, and/or 2.) the effect of the settings on adjustable swaybars is subtle, the major effect coming from the changed diameters and the ratios of diameters between front and rear.

    Good luck. Please post back your "research findings", there are others of us who are interested.

    Regarding the rear swaybar stressing the trailing arms and breaking off "tabs", apparently this does happen. However, the preventative repair is the same as the repair after the tabs break, so there is no real reason to fix the problem before it happens. If they break, then get the reinforced tabs welded on.

    There are other reinforcement systems for the rear swaybar connections to the frame, such as those from Ireland Engineering (I think it's them). They are pretty simple to install; just drill a couple of holes in your trunk pan and bolt the reinforcement on. As I understand it though, it is the trailing arm tabs that break first, so the frame reinforcement kit is for hardcore race set-ups.
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    Brian A

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    granthr

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    Thanks all for the input and reference links. Very helpful. I like the idea of setting the bars to roughly the same location as the stock bars. I will let you know what I do. I will wait on the reenforcements. Right now the car is just used on the street and I am not too agressive. So I might not need the "tab" reenforcements for a while. Now I just need the time and a bit warmer weather to do the job! I can't wait!
    • Member

    granthr

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    Well I got the sway bars installed yesterday! The installation went really well. I was able to thread the front bar in without unbolting anything else. Just took a little patience. I was very glad I bought all new hardware. One of the old bracket bolts snapped off instead unscrewing. So I soaked the rest with PB Blaster and everything else came off with out a hitch. For the rear bar I only had to remove a wheel to get the old one out and the new one in.

    Brian thanks for the tip on compressing the brackets with a vise grip. It was tough to get those started. The tab end really did not want to stay in the body of the car!!! Took quite a few tries to get it to work. I found that once I had it secure with the vise grips to then use a screw driver to line up the two bolt holes. Still took a number of tries though.

    I sized up roughly where the old bars were connected to the connecting links. This ended up being the middle setting on the front and the softest setting on the rear. The new bars are much thicker than the old ones. So I will give this a try for a while, before making any adjustments if any.

    After a initial test drive I have noticed a substantial reduction in lean during cornering. Looking forward to getting it out on some country roads in the next couple weeks.

    Thanks for your advice and input!
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    Brian A

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    Congratulations on getting the new bars installed without having to unbolt anything. Glad too to hear you were able to get those bushing brackets back on. I had a tough time too. (I am sure a pro technician can do it in 3 minutes with one hand.)

    Regarding my set up, I finally found a safe place to turn the 1991 318i at the limit. My current setting (front- stiff, rear- middle) does understeer a little, but more significantly there is significant "shudder" of the front wheels as they slide. Clearly the front bar is too stiff. I'm softening it and retesting.
    • Member

    granthr

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    Just went for an hours drive on a very windy road here in Philadelphia. They just paved it a few months ago, so it is nice and smooth. It is a great 3rd and 4th gear run. Really got a feel for the new sway bars. I looking forward to getting some more seat time in, but an initial thought is I can tighten up the rear one notch. But we will see. It feels great with the body roll greatly reduced.

    Now that I added these sway bars with new hardware and bushings, the car has all new suspension componants. An added benefit to this recent upgrade is that an annoying metalic noise is now gone!!!! :D Prior I would get the noise when going over bumps. So I guess the old sway bar bushings were really shot.

    So now the car is coming into what I want it to be. The next two projects in the coming year are going to be new paint and euro bumpers and hopefully a Hartge front spoiler. Then the dream project with either be a Metric Mechanic 2.2 rally motor (M10) or an S14 conversion. Although, I also want a 325ix. Because if three BMWs are great, then four is even better, right! :cool: Isn't it great to dream! :D
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    stevehecht

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    Grant, what's your current opinion of your H&R sways? I'm thinking of upgrading and I the fact that they're adjustable and priced right. I also like H&R in general. I'm looking for a step up for my Bilstein HDs/M3 springs setup for spirited road driving, and maybe a bit of track time.
    • Member

    granthr

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    I have been very pleased with them! They make a big difference over stock. The handling of this car is now amazing. Although I must say in the past two years every suspension bushing and wear item has been replaced, including rear trailing arm bushings and rear subframe bushings, except the front strut mounts I imagine are original. So the car handles like it is new.

    I have stayed with the middle setting on front and softest on the rear. These settings matched the position of the factory sway bars. I have been pleased with this setup.
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    stevehecht

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    Different bars for different cars

    I'm concerned that adding both a 22mmF/18mmR sway bar will make the ride too aggressive, particularly over rough roads. I'm also wondering whether "more aggressive" sways makes handling in slippery conditions (rain, ice, snow) trickier or easier. I'm sure handling is a heck of a lot better, but how much rougher is the ride?

    I'm considering just upgrading the rear stock 325i from 12mm to 16mm (from Whiteline) rather than going to 18mm with H&R. I'm thinking that going from 12 to 18mm is a rather large difference (the M3 only has 14.5mmR), and perhaps that demands that the front be increased to from 20mm stock to 22. But if I just went from 12 to 16mmR then I would still get a decent bump in handling without having to strengthen the front bar as well and without making the ride too aggressive. Remember, track and autoX are not my priority, I don't know if it's yours.

    I know that V6 Accords normally don't require a front sway because of the increase in understeer, I'm wondering how/why that's different with our bimmers. Adding 20% to my rear sway made a subtle but enjoyably noticeable difference in how the car handled, without a noticeable increase in road chatter.

    Eibach also sells a 16mmR but you need to buy a kit, and Whiteline sells them separately. I could always get a Whiteline 22mmF later if I want to work it in stages.
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    MGarrison

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    That's assuming you can get it later. I used to always think, no problem, I can get this or that anytime! (in general, not just BMW stuff). Then, I wait, and find out it's discontinued, or model changed or the manufacturer went out of business, it's no longer available, yadda yadda yadda. Unless the manufacturer is producing something that's seriously in demand for these now-19-years-old-at-the-newest cars, consider that it's entirely possible what you see available today is dropped tomorrow. If they're selling 20 sets of less-than-race-sized swaybars a year, but thousands for some Honda that's popular in an SCCA auto-x class, guess which one gets discontinued. Just a thought -
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    CRKrieger

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    *Sigh* It would certainly be nice if people truly understood what they're doing when they "upgrade" their cars. Have you ever read a book on suspensions? Do you have the slightest idea what thicker antiroll bars do?

    Springs are your primary suspension media and it is the springs that primarily determine how harsh or soft the ride is. A high spring rate will be harsh and a low spring rate will be soft.

    Shocks are a secondary suspension media. Their job is to control suspension movement but, in doing so, they will influence the harshness of the ride, depending on what shocks they are and how they work. A gas-charged shock may be much softer than a non-gas-charged one with minor suspension movement, but may be much harsher in major travel.

    Antiroll bars are exactly what they say they are. The are the secondary control for body roll (Springs are first.) but they also serve to control, to an extent, oversteer and understeer characteristics. They will normally have no noticeable effect on straight-line driving.

    Without a well-thought-out plan in mind, changing suspension components is not "upgrading", it is only ego gratification. On a micro scale, changing antiroll bars without knowing why is an exercise in futility that can as easily lead to a worse handling car than you started out with. If you have not been through at least several BMW CCA (or similar) driver schools or competed in a season or more of autocross with your car, you probably have neither the experience nor the judgment to be messing around with your suspension. You are, in a very real sense, making the car more dangerous if you do not already know how to safely approach and slightly exceed its handling limits. In changing the suspension, you are generally raising those limits to a level where it takes even more skill to recover from exceeding them - and that is a skill level you do not yet have.

    The bottom line from me is, spend the first thousand dollars on yourself. Take a handful of driver schools. Get the skills and the experience that you will never lose and then make informed choices about changing your car, based on your training, experience and skills.
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    stevehecht

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    Mr. Krieger: The reason I am asking all these stupid and unnecessary questions is precisely because I am trying to have a "well-thought out plan in mind" before I make any suspension changes. I am trying to be as conservative as possible in making these changes and not overmodify my car relative to my driving abilities, just as I was in upgrading the rear sway bar on my Accord.

    If you are trying to say that thicker anti-roll bars do not have any discernible effect for driving on slippery roads, just say so. You say that they have no noticeable effect on straight-line driving, but that doesn't answer my question now does it?

    Please avoid the ad hominem comments in the future if that's possible. FYI I have been to BMWCCA driving school at NHIS and have autoXed a couple of times. I plan on taking another driving school this summer.
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    CRKrieger

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    Sure it does. You asked about harshness. That's going over bumps & stuff. Straight line driving.
    Then maybe you're being too tentative about your decision ... or you're forgetting what you've learned along the way. Either one suggests less experience than you have.

    Assuming you can drive slightly beyond your car's limits (that means getting it to slide in corners while still maintaining the ability to recover), what is it that the car does that you don't want it to do? Does it understeer or does it oversteer? Can you dial that out with tire pressures? If not, then you can look next to antiroll bars to control it. Be aware that they will somewhat affect driving on slippery roads, but not much, since there isn't enough traction to get much body roll. Your concern must be for dry conditions because they will significantly affect your handling then - but only at the limits of traction. If you never go there, there is no reason to change the car. If you do plan to track or autocross it, then you face a compromise where it will be harsher on the street to meet your requirements at speed ... or you choose to continue driving it stock and enjoy it as is.

    Read up on suspension adjustments and learn what changes to antiroll bars affect handling and how they do it. You are the only one who can make the subjective choice about how you expect the car to handle. That primarily come from trial and error once you start installing parts. Because of this, I usually recommend you change only one thing at a time. That way, you know what effect it produced and you can change it back if it's undesirable. Then try something else.
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    stevehecht

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    Thanks, this is helpful and clearly written. My car has some mild understeer when I take it just past its traction limit. I've pretty much decided to take things incrementally (as you recommended) since that's the way I'll learn the most about how serial modifications affect the car's handling and my ability to deal with it. I would first look for a used E30 M3 rear sway that's 14.5mm, a modest bump from the stock 12mm. If it's warranted I would probably then go to a cabrio front bar that's 21mm or one mm thicker than the stock 325i. At that point if understeer is still present at the speeds at which I drive I would go to the 16mm Whiteline or Eibach bar. I don't see myself needing more than that for my current driving habits (but I don't really know!). I wouldn't make a second modification until after the Advanced Driving School in July.

    I did have a question about your comment, "Can you dial that out with tire pressures?" I have been studying the West Texas SCCA "Car Setup and Troubleshooting Guide" that you or someone on this forum recommended. I understand from that guide that understeer can be helped by increasing front tire pressure. I have experienced mild understeer on highway ramps with my pressures up in the mid to high 30s. I'm wondering if I decrease my rear pressure a bit and make the front higher relative to the rear whether that could be an effective means of dialing out understeer? Anyway, I will try it and see. Thanks again for your advice.

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