Suspensions explained, and some options -continued (archive)

The complete automotive resource for buyers, sellers, and owners like you.

4. Dinan Springs (~200 lb in, 1/2"-5/8" lower than stock), with Dinan's Konis or Bilsteins.
Dinan uses shock damping to achieve the ride/handling combination they want. They have specially valved Bilsteins and adjustable Konis. You can go to their website to see what they have. Personally, I'd go for the Konis because of the adjustability.

5. M-Tech springs (194 lb in, 20mm [or 3/4"] lower), M-tech Bilsteins.
The M-tech Bilsteins are specially valved for the M-tech springs to balance out the ride. They have a stiffer than stock ride, but it is still compliant. For people who want to stiffen the suspension, but still want supple ride when necessary, this is a good option. Boge Turbo Gases, Bilstein Sports, and Koni Yellows will fit with these springs, also. The Bilstein Sports are valved with a bit more damping, so they will seem a bit stiffer. Boge Turbo Gases are pretty good too, and similar to the M-tech Bilsteins as far as damping and chassis balance is concerned. Of course, the Konis are adjustable. The M-tech suspension springs and shocks are available through Maximillian Importing Company, and I've already posted all the Part Numbers and information you need about 1 week ago.

6. Bav Auto Sport (~200 lb in, 1.25" lower).
Boge Turbo Gases, Bilstein Sports, and Koni Yellow Adjustables fit. The reason I don't recommend BAS springs is because they don't have a high enough spring rate to compensate for the lower ride height. They wanted to have a smoother ride, and just lower the car. They also needed the spring to be used with different shocks in order to control the amount of suspension travel and "feel." I feel it's too compromised a solution to the problem.

6. Alpina Springs (~200-210 lb in, lower ~15mm or 20mm from stock), Bilstein.
Alpina, just like Dinan, uses their own specially valved Bilstein's to control the suspension damping. The ride isn't much stiffer than stock, but the body is controlled a bit better. What Alpina doesn't do is use bigger anti-roll bars to control roll, such as RD, H&R, and Hartge. This is an expensive option, but one nonetheless for those willing to get a well "tuned" suspension, but not one that has intentions of being TOO high performance.

7. Eibach Springs (~240 lb in, 1.25" lower).
Boge Turbo Gases, Bilstein Sports, Koni Yellows all work with these springs. Eibachs are ok, but I've heard instances where the quality isn't very good and they start to sag and wear out too quickly. It seems they don't last too long. You really can't go wrong with the shocks choices. Boges are generally softer than Bilstein Sports, and Konis can be adjusted from about the Boge damping, to over the Bilstein Sport damping.

8. H&R (~240 lb in, 1.25" lower)
H&Rs are recommended for their quality, and the fact that they're spring rate isn't TOO high. Thus the ride won't kill your kidneys. I've driven cars with Bilstein and the set-up works very well. It may be too bone jarring for the common folk, but for those of you who want a worry-free, stiff, well handling and balanced set-up, and relatively inexpensive, I recommend the H&Rs with Bilstein Sports. Konis are also recommended because you can fine tune the suspension EVEN more.

9. Hartge (~220-240 lb in., I believe the drop is 30mm, but I'm not 100% sure). Bilstein.
Just like the good tuners Alpina and Dinan, Hartge uses specially valved shocks to dampen and tune their suspensions. Hartge also has bigger anti-roll bars, and the complete suspension kit comes with a stress bar. This is a VERY well engineered and very agressive combination. It won't kill you on the streets, but it is NOT for the common man. It is more agressive than Dinan or Alpina. It is expensive though.

10. RD Springs (274 lb-in., 1.25" lower than stock).
Make no mistake, RD Springs are stiff. Boges may be too underdamped for the springs. Bilstein Sports are ok, but make the car porpoise in certain situations. Koni Yellow adjustables are recommended because you can adjust the damping to suit your needs, and to tune the suspension.

In any case, you have to try and figure out what you want from the car, and then set your sights on the best suspension for you.

Generally, if you JUST want to reduce roll, get bigger sway bars and go from there.

Bilstein HD's are a good way to increase the damping on stock springs, and this is what most people will want.

Springs and all that jazz are to increase spring rates, reduce ride height, and reduce suspension movement (travel) and then you use shocks to tune the suspension. What comes out is HEAVILY dependent upon the shocks. This is why a good quality shock is KEY to suspension tuning. Koni Yellow Adjustables are the best offering out there on the market for 99% of the enthusiasts needs. If you're really nutty (and don't like your kidneys), then you can go to coil-overs and all that jazz.

I have bilstein HDs I should have got sports. But, i didn't. So, don't lecture me on why you shouldn't lower shock like these, it is done with stock shocks on new cars all the time. Besides, I am using what I have. I was planning to lower them with H&R springs from BMP, use a stress bar from BMP, racing dynamics sway bars, and upgrade to 16inch wheels with 225/50's. I am trying to accomplish a ride that will not give me as much body lean in turns. With the hd's it is not where i want it to be. Can anyone tell me is this resonable setup that will work? Please help.
josh
thx
535i to is
Colorado

Josh;
Bilstein Hd's are perfect;the sports will be far to harsh for the ride you say you want.
On body lean,that is eliminated more by springs and swaybars,not shocks.I've been setting up e28 cars for years,and my own outcorners "M" cars regularly,using Eibachs,Koni or Bilstein HD's,and RD or SuS.Tec. swaybars.And you still have 85% if a normal road ride.
I use 16x7.5" rims with 205/55/16 or 225/50/16 tires,adding a 3.73LSD diff and 7 series brakes.
Great combination;you have 25% more usable power,M5 handling, BETTER than M5 braking,and it's still comfortable all day long.

Of course,lately I've gone to 17x8.5" rims and 245/40/17 tires,but that's for an instructor's track car.
You also need to reinforce the center swaybar mounts,as well as the rear shock towers if you plan serious driver's school rides,along with new 7 series control arm bushings,and new "a" arm and subframe bushings as well.

Questions, comments, or problems, please visit the Roadfly help desk.