BMW M5 Forum and M6 Forums banner
41 - 60 of 132 Posts
The back & forth on the "right" setup is pretty amusing. I don't fault anyone for choosing one part over another to put on their car, but there are several choices for a reason. I do find all the philosophical reasons for using/not using certain parts kind of hilarious. Its like we're interpreting the constitution in here!

I do really appreciate the first hand knowledge that's being shared so please keep it up.

FWIW the options that seem the best fit to me so far are...
-PSS9 - love that the adjusters are on the bottom of the shock, and I'm not planning on going to a square setup so the known wheel clearance issues aren't relevant to me.
-GC coilovers - I like that they're a US company and that they've worked with M5 enthusiasts to develop their kit. I would probably pick this kit over the PSS9s except I don't love Konis and its lame that on a $2k kit they couldn't come up with a way to adjust rear damping without disassembling the rear seat.
-Intrax/Bilstein - Ride height on this setup looks perfect for me. For the extra $7-900 I might just pop for coilovers tho... been wanting an adjustable setup again since I had KW v3s on my GTI.

As you can probably tell I want a good street setup that offers just a little lowering, something that's not too stiff but I do find adjustability a huge plus as it'll allow me to really fine tune the height and tweak stiffness for the occasional track day.
Not sure why you left BC coilovers off this list. There are a LOT of us running these with very few complaints from what I've seen...hmmm
 
Discussion starter · #42 ·
True they are generally well regarded. I guess for me the downsides to the BC kit are the same as the GC setup, plus they use second-tier (non- Bilstein or Koni) shocks. Right now I'm leaning toward the PSS9s becuase the only downside, well besides the cost, is tire clearance in front. And as I mentioned before I'm planning to stick with staggered Style 65s & 15mm spacers in front so that's not really an issue.
 
if you are making +/- 1/4" adjustment in height from the point which you torqued everything down, I'll agree you do not need to release and retorque in normal position. But changing the height by simply 1/4" on the E39 is not really fine-tuning, not on a street car....you literally cannot, you cannot match the ride and lower the car at the same time.

you cannot change 1 of these without affecting the others:

Spring rates
Shock dampening
Springs travel
Shock travel
Rubber components


and by purchasing coilovers, you are changing all 5 items.

we'll ignore that last bit since you're describing a "Gedankenexperiment suspension" which is clearly unavailable
I would consider 1/4" fine tuning, certainly. If by "not on a street car" you are implying that 1/4" would be fine tuning on a racecar you are mistaken.

A shorter body shock with appropriate valving and a stock-like spring rate would result in the same ride as stock. There isn't any BMW OEM magic here. You can't feel a decrease in shock or spring travel until you run out of it. It would be a balancing act between shorter shock bodies and shorter springs, eventually you would end up low on travel. Would anyone ever do this, no? But could you if you wanted to shell out the money to go this route, absolutely! As for the rubber components? Where do you want them? You could use stock strut mounts or shorter stack height camber plates to gain some travel back, it would take some engineering to add rubber isolators/bushings to avoid NVH but it could definitely be done. I think GC even makes some "touring" style camber plates that are designed with people like you in mind.

I am not familiar with the term you used, but experiment? Sure! It would take some tuning, but you could absolutely build a stock-like adjustable ride height suspension. It would not be cost effective, or ideal, but the statement you are making that you can't lower the car without changing the ride is simply incorrect. I do see the point you are making, but most people who buy an off the shelf coilover kit realize that the car will ride differently, I'm sorry if you were mislead. I don't think the JohnAnthony coilover kit would be very marketable unfortunately, but if you'd like me to start looking into actual components the offer is open.

Back on topic, I think the BC wheel fitment would be better than the Bilstein kit, but maybe not quite as good as GC depending on height since they don't offer the clearanced perch. The springs are smaller than 2.5" OD though, so that is a benefit for sure. Bilstein uses a helper spring on all of their kits IIRC and I would imagine that this is what has such an impact on wheel fitment.
 
I've been looking into upgrading my suspension for the past couple of months and this thread has been a great information resource. I had planned on building a set of Fortune Autos based on some local recommendations but have decided to go with a custom BC set as the FA's are no longer available.

A couple of items should be added and some information updated;
- Fortune Auto has discontinued their coilover suspension for the E39 M5.
- The inclusion of camber plates per coilover brand should be noted as adjustable camber plates generally run around ~$400. For someone doing a full suspension build this can be an unforseen cost.

I haven't looked into all the brands as I was mostly interested in a few; KW V1/2 &ST sets do not come with camber plates. The BCs do include a camber plate.
 
Discussion starter · #50 ·
So after all that research I'm still torn between B8/Intrax and PSS9s. I've regularly been seeing PSS9s in the ~$1600 range, BUT my car will be used as a GT, not a track rat or canyon carver. I guess if I can determine the PSS9s can be made to ride like a street car I will go that route, but its so subjective that I don't know how to get from here to there.

#1stworldproblems
 
I went with Intrax and B8's.

There are a few reasons I went this route. My car is a road car and I don't feel I need 28-way adjustability. I didn't want to deal with going back and forth for who knows how long dialing in my ride height, dampening and finally having the car corner balanced. The cheaper coilover kits have mixed reviews and my thinking was that if I'm going coilover I should go with one of the better setups.

For roughly the same cost of higher end coilovers I purchased the Lemforder 20 piece suspension kit through FCP Euro, X5 bushings, Springs, shocks and other needed items for the refresh.

In return I feel like I have an excellent riding car that sits perfectly and I can drive without having to worry about scraping on speed bumps and other road imperfections.

I replaced the stock suspension and the difference is night and day and I couldn't be happier.

Now, if I tracked my car I may feel differently.
 
I'm sure someone with more knowledge can be more specific as to how the different setups adjust, but this is something to keep in mind...

The rear shock towers are not accessible without removing the rear seat. You will have to get adjustment extenders for the rears and drill through the deck lid so you can adjust them without having to drive around without a rear seat while dialing them in or removing the seat to adjust for different conditions.

Also, there is a set of adjustable coilovers in the group buy thread that seem to have good reviews. The guy selling them uses them on his track car and says they are comparable to higher end setups. I almost pulled the trigger for the $850.
 
Cheap shocks are cheap shocks, period. There is a lot more to be said about this, but I'm on my phone. All of these Taiwanese made shocks are the same (BC, KSport, dgr, Megan, D2, Fortune Auto, etc) and they are made universally using cheap parts, cheap designs, and cheap methods. All of these are perfectly fine for a street car, but they do not have any of the qualities you need in a good track damper.

A good example is shock body adjustment for ride height. They aren't doing this because spring pre-load matters, they are doing it so you can run the same shock body on a mazda 6 and an m5.
 
Discussion starter · #56 ·
One of the reasons I'm considering PSS9s is damping adjustment is on the bottom of the shock. Afaik all other coilovers adjust at the top which makes adjusting after install a *****. I don't want extended adjusters hanging out of the speaker grilles either. I'm a picky sob ain't I?
 
I'm sure someone with more knowledge can be more specific as to how the different setups adjust, but this is something to keep in mind...

The rear shock towers are not accessible without removing the rear seat. You will have to get adjustment extenders for the rears and drill through the deck lid so you can adjust them without having to drive around without a rear seat while dialing them in or removing the seat to adjust for different conditions.
Close, but even after you get the seats out and the parcel shelf out, the speakers also need to be removed to access the shock tower. Depending on your stereo setup coming from underneath may not work either. It wouldn't in my car, Nokia "subs" are in the way.

I just pulled all of this out last weekend in advance of installing new shocks. The whole thing was a massive pain in the *** (2000 w/ DSP + Nokia "subs", folding seats and sunshade), I wouldn't want to have to do it more than once.
 
This is a great thread, but I am still suffering from analysis paralysis. I think I've read every suspension thread in this forum and don't know what to choose.
1. My mechanic says stay oem. He recommends koni on almost everything else, but the e39 oem he says is perfect.
2. The B8 + intrax set sounds very appealing. I want stock like ride height and comfort, but paying a little less and being a little more sporty sounds good as long as it's still a good DD setup.
3. PSS9 adjustments are on the bottom, so easy to get to. I have an affinity for Bilstein as well but it wouldn't let me run my square wheel setup.
4. KWv3 sounds great if i could find them around $2k (maybe Shafro's GB if people would sign up). Do these adjust from the top in back still though?

My M5 currently has 123k on it and i believe i'm still on the original suspension. It's shot. The thing acts like a boat with lots of lean in corners. I want that slop cleaned up, but I still need this to be an acceptable DD and family car. Child seat is in the back after all! I only want a mild drop if any. I want a stock like ride, but I can't even say I know what that is exactly, I have never experienced a fresh suspension in this car. It can't ride like a washboard when I'm commuting on the 405, but it must be hoonable when I get the chance. I'd like to keep my square wheel setup without resorting to huge spacers (I do have the original front wheels if I go with PSS9). I don't care that much about adjustability if it comes setup right in the first place. I think I'm leaning B8+intrax, but I have been waffling for a couple weeks. Help me out!
 
Stay stock, any of the coilovers that do no use the rubber pads will need servicing MUCH sooner than the conventional setups. The Bilstein adjustments are NOT easy to reach and unless you are a trackrack, you'll never touch them. You'll be able to live with the Koni or Bilstein at first, but the novelty will soon run out when you realize that the reduction in bodyroll does not outweigh that increase NVH after the first couple of years.
 
41 - 60 of 132 Posts