[Dinan_Engineering]

Originally Posted by xdnbc

Note: that I realized the front Dinan sway bars wouldn't work, and was trying to figure out if the rear Dinan adjustables would work on their softest settings with my stock front bars- Dinan, have you tried that out?

Accepting the fact that North Americans don't buy wagons, I checked UK and found that H&R make F31 adj front and non-adj rear bars [28fr, 20rr]. These seem to be thicker than the 25/20 Dinans- any idea if the torsion lb rate is similar? If they are, maybe it's possible to use a front H&R with a rear Dinan adj.

It is frustrating for me because I had a Subaru STI that had so many choices for coil overs, sway bars, links, etc; and so many people raced with them, that I knew what worked and what didn't. However, the ride on my car was too stiff for daily driving [but great for racing], so when I quit racing, I bought the best AWD wagon I could find [yes-BMW or Volvo]. I want a softer ride, but still well balanced handling. No real answers yet, but will keep looking. All advice greatly appreciated.

Have not tried it. The back bar should be fine on the F31 though...didn't bother even attempting to physically fit it since the front was always going to be the main question mark and we only list them as sets.

[subzero05]

Originally Posted by JamesNoBrakes

3rd pic is the GC parked next to me.

looks great

[Simons975]

I have a 328i Xdrive. Recently changed to Kelleners sport springs and Bilstein B8. Huge difference and I was really happy with the car until I tracked it yesterday. Way to much body roll in the corners. I never thought I had to change the sway bars too. Looks like another trip to the shop.

[Araemo]

This may not be the right thread, but I don't see a thread for the dinan springs...

I found a lot of posts from people guessing about why there's no sport suspension/lowered options available from the factory on f3x xdrives.. lots of people guessing front CV joints/diff being put out of tolerance by being lowered below stock. What is your stance on the longevity of the front drivetrain components when lowering xdrive? Is there some truth to the suppositions, and you designed your spring set to stay within tolerances, or was it all just ill-informed guessing?

I haven't taken delivery of my 340 yet, but the springs and sways will be on my radar if I'm not happy with the m adaptive suspension.

[Dinan_Engineering]

Originally Posted by Araemo

This may not be the right thread, but I don't see a thread for the dinan springs...

I found a lot of posts from people guessing about why there's no sport suspension/lowered options available from the factory on f3x xdrives.. lots of people guessing front CV joints/diff being put out of tolerance by being lowered below stock. What is your stance on the longevity of the front drivetrain components when lowering xdrive? Is there some truth to the suppositions, and you designed your spring set to stay within tolerances, or was it all just ill-informed guessing?

I haven't taken delivery of my 340 yet, but the springs and sways will be on my radar if I'm not happy with the m adaptive suspension.

Pure speculation on my part as to guessing what BMW's reasoning it but but the drivetrain is fine when lowered (assuming its not aggressively lowered which causes its own problems). What we have found in general is the xDrives when lowered are a bit more harsh on the ride quality in comparison to the RWD counterparts. Its not horrible by any means but when the philosophy of BMW is comfort, anything that goes against that is an automatic no-no. If you were to upgrade shocks/struts the xDrive w/o the M Adaptive Suspension would be the platform that serves the most benefit from doing so.

[Araemo]

Originally Posted by Dinan_Engineering

Pure speculation on my part as to guessing what BMW's reasoning it but but the drivetrain is fine when lowered (assuming its not aggressively lowered which causes its own problems). What we have found in general is the xDrives when lowered are a bit more harsh on the ride quality in comparison to the RWD counterparts. Its not horrible by any means but when the philosophy of BMW is comfort, anything that goes against that is an automatic no-no. If you were to upgrade shocks/struts the xDrive w/o the M Adaptive Suspension would be the platform that serves the most benefit from doing so.

Thanks. I am also considering just getting the sway bars here, and keeping stock springs/ride height.. One of the benefits to the adaptive suspension is that you can use softer springs while still controlling wheel movement well due to the damping control.. ditching that benefit by going to stiffer springs is questionable to me. But again, it'll all depend on how I feel about the car once I've gotten to drive it on my favorite roads. Also, since I live in snow country (AKA pothole country), the 'comfort' option is one of the big reasons I opted for the adaptive suspension. My normal commutes are NOT on smooth roads.

[Musashi]

Originally Posted by JamesNoBrakes

ACS Sport springs
Dinan Shockware
Dinan F 3x Swaybars
P-zero something or other 245x40s

.

Hey James, just read your post, great description. Curious, how did it fare 18 months later, and why ACS vs Dinan springs? thank you.

[RM7]

Originally Posted by Musashi

Hey James, just read your post, great description. Curious, how did it fare 18 months later, and why ACS vs Dinan springs? thank you.

They don't make Dinan springs for 4-series X-drives, or at least they didn't when I bought the ACS. Dinan was having trouble getting anyone with these cars to come in and get the engineering done at their location.

But anyway, the ACS springs worked great, seemed to be engineered well for the car's weight (rather than a one-size-fits all like the H&R and a few other companies). I had shockware done too, which I highly recommend if you are going to increase the spring rate-you have to increase the damping at the same time.

[Versipellis]

Originally Posted by JamesNoBrakes

They don't make Dinan springs for 4-series X-drives, or at least they didn't when I bought the ACS. Dinan was having trouble getting anyone with these cars to come in and get the engineering done at their location.

But anyway, the ACS springs worked great, seemed to be engineered well for the car's weight (rather than a one-size-fits all like the H&R and a few other companies). I had shockware done too, which I highly recommend if you are going to increase the spring rate-you have to increase the damping at the same time.

They have them now, but apparently not for F36's?

[Musashi]

Originally Posted by Araemo

Thanks. I am also considering just getting the sway bars here, and keeping stock springs/ride height.. One of the benefits to the adaptive suspension is that you can use softer springs while still controlling wheel movement well due to the damping control.. ditching that benefit by going to stiffer springs is questionable to me. But again, it'll all depend on how I feel about the car once I've gotten to drive it on my favorite roads. Also, since I live in snow country (AKA pothole country), the 'comfort' option is one of the big reasons I opted for the adaptive suspension. My normal commutes are NOT on smooth roads.

Just did it. What a transformative experience! Waited until having a full summer with it, all R&D issues ironed out (which eliminated H&R as contenders due to low performance and spring rate). Had everything installed (sways, springs, handling kit + ER charge pipe) two days ago.

Everything Dinan_Engineering or JamesNoBrakes say in their comments/review is accurate. They were also helpful with spec requirements and instructions.

• Car dropped 17-18mm;
  Old sways 12.5mm to 18, and 22 to 25 higher grade;
  Car hugs the road;
  Accelerates faster (0-60 coming up, was 4.3-4.4 before);
  10-20Km/hr min gain in cornering speed around 100-140 km/hr. Stable cornering, flat on apex, quick curb exits, no roll. Under-steering was the concern prior; now, tyre temp, grip and learning over-steering limits;
  At speed, a bit noisier esp frontal or angled wind effect (strong gusts), harmonic resonance sound of the spring system. In my case, it was noticeable with 40+km/hr gust winds;
  Stiff suspension. For the first time, felt the need to drop to Comfort mode on iffy roads, or be cage rattled. It works!!;
  Iffy bumpy roads with deformations are now silly shaking in sports mode, so must now be driven slower and in Comfort mode. I LIKE THAT, as at least I have options;
  Smooth roads? A bliss;
  Steering is direct, sensitive and Q4 2014 ZF, relatively light. Pre-upgrade, understeering and Michelin 235 fronts increased steering resistance significantly - though not as bad as the artificial 340i feel. The upgrade eliminated the resistance and the variable steering is back to light/Variable steering;
  Bad roads? I used to avoid them before, will not change. Anything that forces slowing down on a road is smart anyway;
  Alignment close to Dinan recommendation, though -1.38Deg rear and not -1.5. Will see how wear evolves;
  Throttle response improvement - slight, ER does its job.

These work with the Dinan Shockware Adaptive program, installed a year ago. The upgrades eliminate any considerations I may have had towards the 340i, as I exceeded specific cornering benchmarks that I noted when driving 340i M Performance Demos. 340i would also require suspension upgrades.

Driving it, I understood the trade-off design philosophy of the OEM springs. Lower spring settings, even 18 mm, is more uncomfortable but multi-fold sporty. Noisier. Drivers uninterested in driving dynamics would find it too connected, too sporty. BMW could have offered a better option, but there may have been no R&D interest in the F3x chassis. At least Dinan did that homework. Yet, clearly, some lessons were incorporated in the 340i, which I suspect mainly Adaptive Flash, a stiffer ZF rack and the rear multi-link change. Yet R&D is not easy- some known brands offer generic products, springs bottoming out or spring rate ill-suited to Adaptive M. For example, although lower, I scrape less the lip in one particular location, as the car does not bounce up or down anymore. So higher, softer BMW OEM spring was worse in that aspect than the lower Dinan.