whitels

I have the Bilstein/Eibach combo. When I am driving alone, the ride seems to feel more both the bumps on local streets and expansion joints on freeways. You hear more body creaks to accompany the bumps. I like the control, and firm yet supple feel and of this setup. But the increased bumps transmitted and felt in the cabin is not pleasurable. I miss the smooth OEM suspension but I don't miss it's lack of control and tendency to wallow.

Then, when I have my family riding (3 adults, 1 kid), the suspension changes its characteristics. It now can soak all those same bumps resulting in the car feeling much smoother--just like a Lexus It is still firmer than stock but very well controlled. I suspect the extra weight of the passengers help the weight of the body to push down on the suspension and therefore keep the car in that level longer, in other words- the extra weight minimizes the car's tendency to bounce up from a road bump as the extra weight is holding it there.

I want to have this smooth effect even when I am the only occupant in the car. I am theorizing that maybe what I need is to just put back the OEM springs and retain the Bilstein. As an FYI, these are the conditions of my driving: I drive on 70% freeways and 30% streets. I have 17" OEM rim on Dunlop Sport SP5000 pumped to 37psi. I have tried to do 32psi, it helps only a tiny bit but I think it can cause a considerable wear on the tire. I think that 37psi is optimum for this setup so I will keep that setting.

I have two questions:
1. Would I get my desired result or closer to it by replacing the Eibachs with OEM springs on Bilstein shocks? (I hope no one would suggest to put more stereo equipment to add weight and get the ride I want ;-) LOL)
2. I like the slightly lower stance of the Eibachs. I don't want it any lower coz the car's rear had been scraped a few times approaching a driveway when fully loaded with passengers. Should I cut the OEM springs a little bit, or is there an aftermarket spring out there that will deliver OEM rate but lower the car only 1"?

Experts...your opinions please.

RON430

Perception of ride quality is such an individual experience that I would think most experts would be hesitatnt to give much of an opinion. I have not tried different springs but I do have the bilstein sport shocks with the stock springs and 16 inch tires. My experience is that the issue you describe, that is a firmer ride with a lighter load, is related to springs more than anything. The bilsteins alone made a huge difference in both the handling and the ride. I never found the stock ride to be particularly comfortable, but that is my own taste and should be included. I was so impressed by the bilsteins alone, I had no interest in changing the spring rates (I really don't care about the looks issue from dropping so that is a non issue for me). After driving the car for a while, the only complaint I had was roll stiffness which should be adjusted with other means than springs and shocks. That is why I put the TRD blue sways on. Both my wife and I didn't notice any significant change in ride with the sways but in corners, especially high speed sweepers, the car is rock steady which is the feel I wanted.

As I am sure you know, we have some roads here in Cal that are getting pretty bad and the stiffness in my GS is still marginally too stiff to my liking. You may want to attribute some of this to my old fart status but my most recent experiences in a 540 and the new 745 have given me the impression that they are now too stiff for my taste for day to day driving. Unfortunately, the only way to tell if the stock springs is a better choice is to go back and put them on and try them for a few weeks. Overall, I am very pleased with the handling of my setup and have both the bilstein sports and TRD sways for my wifes new GS3 to go on when we get the time.

One last point. I know the Lexus recommended pressures for the tires but I find them too annoying on the 16s. Whenever we go in for service, Lexus always runs the tires up to 35 lbs (both my GS4 and her new GS3 which has been in for one service). I set them at 30 lbs and to both my wife and I, the ride is much better and quieter as well. I am watching the tire wear with a Longacre tread depth gauge which can be read pretty reliably to an eighth of a sixteenth (around .007 of tread depth) and I have no unusual wear developing on my Michelins (18,000 miles on the GS4) or on the Yokohama AVS dbs (about 3000 on the GS3 - my wife complained loudly about the noise from her stock Michelins and to Lexus credit, the dealer replaced the tires with whatever she wanted, she chose the Yoko's). Obviously I have 55 series tires and I know the lower profile tires need to be pumped up higher but low profile tires running at the higher pressures that some guys have mentioned here will always give a very firm ride IMHO.

Hope this helps.

GS4Will

i would not advice cutting springs...

whitels

RON, you hit a few things that I was also lamenting about the GS suspension. First, it was never comfortable to begin with. Coming from the LS camp, I know that would be the obvious observation but you coming from the bimmer side, it underscores that observation even more.

Secondly, as an old fart myself, I am not too keen into lowering but only to a certain degree. I already have the Eibachs when the Bilstein arrived so I just decided to try it on thinking that Eibach's "progressive" rate will approximate the stock or close enough to it. It's been about a month now and I am still trying to convince myself that I like the "stiff" ride. Freeways are great when they are paved well. The ride is smooth and very well controlled. Thanks to the Bilstein and the Eibachs. Other than that, it's on the bit of a bumpy side. It's not punishing in any way, though, which is something that I can live with. But as a fan of perfectionists (hey that's why we all drive the Lex), I want it a certain way--which fortunately I found can be achieved in the GS by loading the car with people!!!.

I don't want to spend the money on the coil-overs so that's not going to be in the equation. If you have driven the IS300 stock, it's suspension, I think, is perfect. Just perfect for my taste. I can describe it as soft enough to absorb most bumps but firm enough to feel like it's a go kart!

So you think that the load-related firmness is a spring rate issue. I think I will be heading soon to put back the OEM springs in unless someone can recommend a more appropriate spring for the ride characteristics that I am looking for.

By the way, Lexus amazes me when they do things like that as they did for your wife's GS- replacing the tires because it's too loud for her. Other dealers would simply say "that's how it is from the factory, and all GS's are like that, sorry...".

Thanks for your input. This is well appreciated.

whitels

Hey Will,
Tell me more about it. I think I've read this advice somewhere also but I don't exactly know the underlying reason.

If you cut the springs such that the drop is 1.5- 2", then I suppose it will not be good as you'd probably hit the end of the suspension travel more often than is necessary.

If you cut it for a 0.5-1" drop, hope that's better than the above but is this still considered not advisable?

You know about springs here than most anyone, is there anything out there with a 1" drop but with spring rate equal to OEM or even a tad softer? I have the Bilstein shocks and I think since this shock is firm to begin with (relative to OEM), I am guessing I can run a softer springs for a combined effect which perhaps is what I am looking for.

whitels

DoubleWhoosh

The problem you are experiencing is the fact that the Bilstein shocks are valved pretty aggressively, which seems to be a little too much for some users. The damping of the shocks is along the lines of a shock for a full size truck, which is exactly why your car rides better when you have a bunch of people in it!

I've seen the shock dyno data on these shocks, and I think they were going for an extremely sport type setting, not taking into account the actual use of street driven GS's.

Haven't tried those shocks yet with the stock springs, but I suspect it won't help much - the sharp and jiggly bumps will probably behave about the same.

whitels

Thanks for a well laid out analysis. I, too kind of suspect that putting back the OEM springs won't help much but I also suspect that it will be a tad better. However, since RON430 has that setup and he's happy, I thought it's worth a try. The only difference is that he has the 16" tires.

Have you seen the shock dyno data for the L-tuned shock? That may be the way to go if you think about it. I would think that it has less aggressive stiffness as compared to the Bilsteins.

The days are counting before I take out the Eibachs. But your analysis puts a different spin in some ways. Maybe L-tuned shocks are the answer.

If only someone here can confirm that the L-tuned setup is similar to the stock IS300, then that will help a bunch.

Experts...keep 'em coming. THANKS ALL!

RON430

LIke most things, I agree and disagree. When you put more load in the car, the spring compresses slightly which actually increases jounce/rebound bias somewhat due to the slight initial compression ( the spring will easily extend but have even more force applied to further compression). The shock piston moves up or down and then stops and all the valving resets with no piston movement. Once there is an excursion to the suspension, the shock valving takes over to damp the oscillations of the spring but the shock did not care whether it started from an unloaded position or a loaded position, it just starts from rest and induces the same dampening on the suspension action regardless of where the suspension originally started out from, by normally affecting the bleeding rate of the fluid from one side of the piston to the other. That explanation, and now coming up on almost forty years of working on/modifying car suspensions was the reason I generated the comment that if you feel a different ride action with loading it is most likely springs, not shocks. While I personally don't find bilsteins harsh, they are definitely quicker to respond than the stock shock. In fact, when I read about the valve that opens on the stock 2k1 GS4 shock to essentially remove the damping force when the shock piston moves very quickly, I was apalled. This is exactly what you don't want to do if you want to maintain control of the suspension. I believe the new GS shocks are quite a bit different than the 2k1 stock GS4 shocks and that is a good thing. At least my wife's new 2k3 GS3 has a much better ride in stock condition than my 2k1 GS4 although I already have the bilsteins ready to go on. Even though we may both qualify for old fart status (meaning both my trophy wife and I) we both prefer controlled rides (and a reason why we don't particularly like most stock honda's and acura's) so the bilsteins go on and I have the TRD sways for her car already as well. I just think the car rides better. I believe the stock bimmer shocks are Boge (someone will probably jump all over me if I am wrong) and one of the few improvements I saw to the bimmer in both ride and handling was going to bilstein sports. I just don't find the bilsteins harsh in most any way. Of course this comes with the standard shock proviso. If you have worn out shocks, you will always notice a degradation in the softness of the ride with new shocks. The old ones probably have leaked out all their oil and are doing nothing so the ride is quite floaty and soft. When you put new shocks on, regardless of brand, the ride gets noticeably firmer and of course it slowly softens as the shocks wear. I put the bilsteins on my GS with about 1700 miles so I didn't notice the ride change much at all, but handling improved a bunch. My wife's GS has about 2500 miles and I doubt she will notice much difference in ride (although it will have to wait until the $6,000 in body repair from the Mitsu SUV that smacked the rear end of a seven week old GS- you really don't want to know, we are both still pretty pissed, I just hope his insurance goes up to $10K a year).

Obviously, there are bilstein HDs which are valved softer than the sports but boy does this get pricey (not only the parts but the installation/alignments, etc.). This is the best reason for adjustability. I am a big fan of the stock bilstein valving, for me it is about perfect. But I acknowledge that everyone's buttometer is different. I believe that there are some coilovers talked about here that are not only adjustable for ride height but both jounce and rebound of the shock as well. In the long run, this could be a very attractive solution although the disadvantage of the coilover is the spring that the unit comes with, it may not be to your liking. While I applaud the attempt to publish spring rates on the coilovers please don't forget that modern springs are all progressive and the rate which they go from the soft rate to the firm rate has a big effect on ride. Further proviso, the suspension really needs to be viewed as a whole for ride/handling. Spring rates, shock valving, roll bar rates, chassis stiffness, vehicle weight, COG location, tire sidewall stiffness, tire pressure, etc. all go together to give you the resultant ride/handling.

As for cutting springs, most people today have no idea what cutting springs is all about. Back in the 60's, there was not a great deal of aftermarket parts available for cars. If you wanted to lower, say a camaro, you had to cut the front spring and install a spacer between the leaf spring and the rear end housing (you could re arch the leaf springs but let's not go there, OK?). Cutting a spring is definitely not preferred if you can get the correct spring. Reasons? If the spring is not cut properly, you end up with two springs with different rates and ride heights and a car that just doesn't handle well and you can't figure out why. When the coil is cut, the spring must be further heated and the end of the coil bent down to provide the proper seating in the spring perch. If the guy cutting doesn't know some metallurgy and is empathic to heating and cooling rates, you end up having that bent down portion snap off, which also ruins your day. So, all things considered, should you cut springs - I sure as heck wouldn't. But a lot of people have cut a lot of springs and the world didn't end. Even won races and autocrosses with cut springs. While there is a definite blurring between the function of the spring and the shock, they still do different things and you need to be pretty clear on what the spring does and what the shock does and what the car is telling you - like ride with different loading. If you do feel the shock is the problem, maybe you can find an adjustable shock to use your Eibachs with. Might be an intemediate cost approach. The more you know about how all the pieces of the suspension work and what they contribute, the better idea you get of what to change. And, while not at all cost effective, changing only one thing at a time is preferred if you are trying for a certain ride result. If you are just looking to get as many aftermarket parts on the car as possible, it is a lot cheaper to do them all at once. Good luck.

whitels

RON430,
As always, I appreciate your input and welcome them anytime. I have read it twice and is really helping my thought process.

Thanks again.

whitels

oldguy

Not the expert that RON430 is, but do have Bilstein sport and stock springs, and 16" tires. For now. 17's on the way.
I get some bad moves from speed bumps in parking lots at slow speed, only in the rear. Goes away with weight in the back seat. I've thought that the Bilstein HD would probably not do that, but am unwilling to give up the control. (Or spend the money). I expect some further degradation when the 17" wheels are on, and I do have my snows at 35lb. The shocks feel like they will not move fast enough and clunk on the rebound. It's not when I first hit the speed bump, but on the other side, when the shocks are getting longer. I don't think I'm expressing this well.
Having said all this, I'm very happy to have them. 99% of the time, a big plus.

DoubleWhoosh

Well, all the analyzing in the world won't change the most important thing...if you don't like the ride of your car because of something you did, you just plain don't like it. The hard part is that there are different tastes for everything, so what someone says is right for you, may still not be right. The only real test would be to either try it yourself, or at least if you are lucky to find someone that you can go for a ride in their car and see for yourself i you like it or not.

The main thing is for you to be happy with your car...that's what all this aftermarket is all about!

Sometimes one might expect too much from something though, so there will be some type of compromise somewhere, that's just the way it is too unfortunately.

RON430

At least one of the real strengths of this board is the exchange of information. But, as DoubleWhoosh said, so much is subjective, like ride and handling, it is difficult to do real apples to apples. What is just right for one guy is too harsh for the next and too soft for the next (yeah, the Goldilox syndrome). And I hesitate to mention it but adjustability doesn't always help. You can go crazy trying to adjust things and end up just fiddling your brains out but never quite getting it right. One more old fart story, I rememer when we discovered brake proportioning valves and putting them in the cockpit to make them driver adjustable, the GM valve which was around $10 was just magnificent with a big ol' screw thread to run in between no front to no rear brakes. When racing, especially with the early TA cars, there was a tendency to just keep screwing that valve in increasing the bias to the fronts. This would keep up until you had the bias so much on the fronts that they locked (with virtually no rear brakes) and off you went to plow grass. The driver adjustable brake proportioning valve stayed but the amount of adjustment that the driver could put in was severely limited.

Bilstein has done adjustables but they don't seem to be a big fan of it. The other adjustables I am familiar with are the Tokico (single) and Koni (I think both single and double adjustable) and both of them are more harsh on the street than the non adjustable bilstein in my opinion. Don't have any other experience with the current crop of adjustables. Trying to remember but wasn't Eibach going to do a line of shocks? Did they ever do it? Did they ever do it for the GS? Just hate to mention it because it does get expensive. I have never really been a fan of the bilstein HD, although I can't say I even know anyone who used them. Maybe they are an alternative here, but they are more expensive than the sports for some unknown reason. Anyone tried them?

whitels

I actually test rode in a car with a Bilstein setup before I did my own mod. That was compliments of Jawnthen- a CL member. He had H&R springs which are regarded as stiffer than Eibachs and the ride was fantastic. I actually put a review here on CL touting the setup as more comfortable as OEM and there's no doubt in my mind that it really is. I said, if that was comfy, then Eibach- being softer- would be more comfy, if not the same.

Looking back, I remember now that Jawn's car was loaded with stuff when I rode it. Aside from the huge stereo speakers in the trunk and amps, he also had his travel things and the the trunk was full. As things are unfolding now with my setup, it is becoming obvious that it was the weight factor on Jawnthen's car and how the suspension reacted to that weight as my basis for judging the fine ride. I can now see that loading my car would have the same comfy effect just as in Jawn's car.

Bottomline, after all of this analysis and points and counterpoints which really helped me --thanks to you guys -- I think there's good reason to believe that I should switch the spring back to OEM and see how I would like it. I'll report back.

sho3000cc

MAY I SUGGEST YOUR NEXT TIRE TO BE .....POLE POSITION SO-3 POTENZA'S...THEY ARE STICKY AND HAS THE MOST SMOOTHEST RIDE FOR A "Z" RATED TIRE!!! THE BRIDGE-JOINTS ARE NOT AS LOUD AND THE BUMPS ARE SMOOTHER. 235 45 ZR17 OR 245 45 ZR17! GOOD LUCK CJJ

dipstick

I will probably read these posts 2 or 3 more times, just for the info. I already have the L-Tuned springs and shocks, and the mid-stiff TRD Sportivo sway bars with stock 17x8" alloy wheels. I have "fat" tires (mostly for looks and ride quality) 245/45 with +45mm offset in front, 255/45 with +35mm offset in back. My ride quality is so good I consistently think "Man, this ride is so great!" while at the same time I have improved handling, good turn-in, and limited body roll. I could have more sporty handling and flatter cornering with 35/40 profile tires and the TRD race sways, but I am happy with the softer setup for ride comfort. I have absolutely no harsh bumps, and on good roads, I still have a near luxury ride. I almost succumbed to the mod bug and came close to buying 18" wheels, but with the L-Tuned drop and the fatter tires, the 17" wheel proportions look just right to me. Naturally, everyone has his own idea of how the car should look, and lots of the 18-19" setups look great too. I will try to post some photos soon so you guys can see what it looks like with this setup. I have had two Corvettes with Bilstein shocks, and you couldn't get a better quality shock for ride and control, imo. If Lexus would honor the warranty with the Bilsteins as well as the L-Tuned shocks, I would have bought the Bilsteins. I don't know much about the Eibach springs, but my guess is that the L-Tuned springs are probably just about the same, maybe even made by Eibach. Good luck on your decisions.